FANUC AC servo drive system failure repair 30 cases

Abstract: 6.1.2 FANUC AC servo drive system failure repair 30 cases of
Example 231. Job after a few hours of intense vibration fault repair
Fault phenomenon: a used CNC FANUC 0T CNC lathe, normal boot-up of all action, high-speed servo-feed system sports a smooth, low-speed non-crawling, processing of all parts meet the required accuracy. When the machine to work after 5 ~ 7h (time uncertain), Z-axis oscillation radical, CNC alarm, machine tools not work correctly. At this time, even starting off again, as long as the manually or automatically moving Z-axis, in all speed range, there are drastic oscillation. However, if the shutdown time long enough (such as: the second day of boot), machine tools can be a normal job 5 ~ 7h, and again more than failure, so cyclical repetition.
Analysis and treatment process: the machine tool X, Z, respectively, using FANUC 5,10-type AC servo motor drive, spindle drive spindle FANUC 8SAC used machine with Hydraulic Clamp, Hydraulic Tailstock and 15 knives automatic tool changing device, the whole closed protection, auto-Chip. Therefore, the control circuit design more complicated, more powerful machine.
Fault Based on the above phenomenon, starting with a big consideration, analysis of possible causes nothing more than mechanical, electrical two aspects. In the machinery, may be due to the paste of hot plastic deformation of rail, degumming, ball screw, lead screw bearing partial damage or cause improper adjust the non-uniformity of load changes, resulting in feeding system instability. In electrical connection, may be due to changes in the parameters of a component, causing the system to change the dynamic characteristics, resulting in system instability and so on

In view of the machine used is a semi-closed-loop servo system, in order to distinguish the reasons, the first step is to repair loose Z-axis servo motor and ball screw mechanical connection between, in the Z-axis no-load, the running processes to distinguish between mechanical, electrical fault. Found by the test: fault still exists, but failure to extend the time. Therefore, we can confirm the reasons for an electrical fault, and the temperature rise and load size or relevant.
Because of numerical control machine tool servo feed system includes a CNC, servo drives, servo motor, such as the majority of three, in order to further distinguish the reasons, the second step is to repair CNC X-axis and Z-axis to set the speed and position feedback Swaps (CNC's M6 and M8, M7 and M9 swap), namely: the use of the X-axis CNC machine tool commands to control the Z-axis servo and motor sports, CNC Z-axis directions of the X-axis control machine tool servo and motor sport in order to determine fault happened in the CNC or the servo. After the replacement was found, when the Z-axis CNC (with X-axis servo and motor) and normal exercise, but the X-axis (with Z-axis servo and motor) sport when oscillation. Accordingly, the fault can be confirmed in the Z-axis servo drives or servo motor.
Taking into account the machine tool X, Z axis are used in the same series of AC servo drives, the servo PCB board the same type and specifications, in order to further narrow the scope of the inspection, repair of the third step is the second step in the resumption of CNC and X, Z servo the normal inter-connected, will be X, Z of the PCB board after the swap, after adjust settings. After the exchange of discovery, when X-axis is still normal, Z-axis is the same fault.
Based on the above test and inspection, can confirm that the failure was because of Z-axis servo main circuit or servo motor caused by the bad. However, because of X, Z motor specification difference between the larger, on-site without the same type of servo drives and motors available for exchange, it can no longer use the "swap method" for further identification. Taking into account the servo main circuit and servo motor structure is relatively easy, it adopted the principles of analysis to conduct the following inspection, concrete steps are as follows.
1) Analysis of servo main circuit. After the previous inspection, the scope has been narrowed to fault servo main circuit and servo motor, the then editor of the subjective view that the main servo loop, in particular, are a long time because of the inverter power control in high-voltage, high current conditions, the parameters change with temperature more likely to change the value. To this end mapping of the actual AC drive main circuit schematic diagram (as shown in Figure 6-1) (Note: Later, the facts have proven that the author of this step is not right to judge, but in order to accurately reflect the repair process, and reader-friendly system reference, it is still part of the contents of this list).
Figure 6-1 is based on physical mapping of the FANUC AC servo main circuit schematic diagram (plate number: A06B-6050-H103). According to schematic can be analyzed to determine the figure of the role of the various components are as follows:
NFBl into the line circuit breaker for, MCC main contactor for the servo, ZNR into the line for over-voltage suppressors. VA ~ VF to DC rectifier circuit, TA ~ TF for PWM inverter main circuit. C1, C2, C3, R1 for the filter circuit, V1, V.

Abstract: 6.1.2 FANUC AC servo drive system failure repair 30 cases of

Example 231. Job after a few hours of intense vibration fault repair

Fault phenomenon: a used CNC FANUC 0T CNC lathe, normal boot-up of all action, high-speed servo-feed system sports a smooth, low-speed non-crawling, processing of all parts meet the required accuracy. When the machine to work after 5 ~ 7h (time uncertain), Z-axis oscillation radical, CNC alarm, machine tools not work correctly. At this time, even starting off again, as long as the manually or automatically moving Z-axis, in all speed range, there are drastic oscillation. However, if the shutdown time long enough (such as: the second day of boot), machine tools can be a normal job 5 ~ 7h, and again more than failure, so cyclical repetition.

Analysis and treatment process: the machine tool X, Z, respectively, using FANUC 5,10-type AC servo motor drive, spindle drive spindle FANUC 8SAC used machine with Hydraulic Clamp, Hydraulic Tailstock and 15 knives automatic tool changing device, the whole closed protection, auto-Chip. Therefore, the control circuit design more complicated, more powerful machine.
Fault Based on the above phenomenon, starting with a big consideration, analysis of possible causes nothing more than mechanical, electrical two aspects. In the machinery, may be due to the paste of hot plastic deformation of rail, degumming, ball screw, lead screw bearing partial damage or cause improper adjust the non-uniformity of load changes, resulting in feeding system instability. In electrical connection, may be due to changes in the parameters of a component, causing the system to change the dynamic characteristics, resulting in system instability and so on.
In view of the machine used is a semi-closed-loop servo system, in order to distinguish the reasons, the first step is to repair loose Z-axis servo motor and ball screw mechanical connection between, in the Z-axis no-load, the running processes to distinguish between mechanical, electrical fault. Found by the test: fault still exists, but failure to extend the time. Therefore, we can confirm the reasons for an electrical fault, and the temperature rise and load size or relevant.
Because of numerical control machine tool servo feed system includes a CNC, servo drives, servo motor, such as the majority of three, in order to further distinguish the reasons, the second step is to repair CNC X-axis and Z-axis to set the speed and position feedback Swaps (CNC's M6 and M8, M7 and M9 swap), namely: the use of the X-axis CNC machine tool commands to control the Z-axis servo and motor sports, CNC Z-axis directions of the X-axis control machine tool servo and motor sport in order to determine fault happened in the CNC or the servo. After the replacement was found, when the Z-axis CNC (with X-axis servo and motor) and normal exercise, but the X-axis (with Z-axis servo and motor) sport when oscillation. Accordingly, the fault can be confirmed in the Z-axis servo drives or servo motor.
Taking into account the machine tool X, Z axis are used in the same series of AC servo drives, the servo PCB board the same type and specifications, in order to further narrow the scope of the inspection, repair of the third step is the second step in the resumption of CNC and X, Z servo the normal inter-connected, will be X, Z of the PCB board after the swap, after adjust settings. After the exchange of discovery, when X-axis is still normal, Z-axis is the same fault.
Based on the above test and inspection, can confirm that the failure was because of Z-axis servo main circuit or servo motor caused by the bad. However, because of X, Z motor specification difference between the larger, on-site without the same type of servo drives and motors available for exchange, it can no longer use the "swap method" for further identification. Taking into account the servo main circuit and servo motor structure is relatively easy, it adopted the principles of analysis to conduct the following inspection, concrete steps are as follows.
1) Analysis of servo main circuit. After the previous inspection, the scope has been narrowed to fault servo main circuit and servo motor, the then editor of the subjective view that the main servo loop, in particular, are a long time because of the inverter power control in high-voltage, high current conditions, the parameters change with temperature more likely to change the value. To this end mapping of the actual AC drive main circuit schematic diagram (as shown in Figure 6-1) (Note: Later, the facts have proven that the author of this step is not right to judge, but in order to accurately reflect the repair process, and reader-friendly system reference, it is still part of the contents of this list).
Figure 6-1 is based on physical mapping of the FANUC AC servo main circuit schematic diagram (plate number: A06B-6050-H103). According to schematic can be analyzed to determine the figure of the role of the various components are as follows:
NFBl into the line circuit breaker for, MCC main contactor for the servo, ZNR into the line for over-voltage suppressors. VA ~ VF to DC rectifier circuit, TA ~ TF for PWM inverter main circuit. C1, C2, C3, R1 for the filter circuit, V1, V2, R2, T1 for the DC bus voltage control loop. R3 for DC bus current sense resistor, R4, R5 for the servo motor phase current sense resistor, R6 ~ R8 for the servo motor braking resistor energy consumption.
By the static measurement, the above components at boot time and downtime happened after there was no significant change in its parameters, and in the normal range.
For further analysis to determine, in the event of failure, on the main circuit of the practical work carried out by measuring the following analysis:
The DC rectifier circuit, if the VA ~ VF normal, then when the input line voltage Ul for 200V when, A, B between the average DC voltage should read as follows:
UAB = 1.35 × Ul = 270V
Taking into account the role of capacitor C1, the actual average DC bus voltage rectifier voltage should be 1.1 ~ 1.2 times, that is about 300 ~ 325V. Actual measurements (in the actual servo unit for the CN3 and CN4 of 5 feet between the foot of one), this value is normal, you can determine the VA ~ VF without fault.



The main component parameters: C1: 680μF, C2: 1200μF, C3: 3.3μF, R1: 20kΩ
R2: 16Ω R3: 0.12Ω, R4/R5: 0.05Ω, R6/R7/R8: 0.6n
Figure 6-1 servo drive main circuit schematic
For DC bus control circuit, if V1, V2, T1, R2, R3 normal job, then C, D between the DC voltage should be slightly lower than A, B between the voltage, the actual measurement (in the actual servo unit for the CN4 1 feet and 5 feet between the CN4), this value is normal, can be judged more than trouble-free components.
However, TA ~ TF measuring the composition of output PWM inverter main circuit (T1 terminal of 5,6,7), V-phase voltage is sometimes found Tong phenomenon when broken, it should be judged in the V-phase fault.
To further confirm that repair will be U-phase inverter transistor (TA, TB) and V-phase inverter transistor (TC, TD) made a swap, but the phenomenon of the same fault.
After the above checks can confirm: the cause of the malfunction in the servo motor.
2) The servo motor inspection and repair. Confirm the scope of the fault after the servo motor on a careful examination, and ultimately found the V-phase motor insulation resistance in the failure of smaller, when placed after a longer period of time, but also back to normal. To this end, the following steps to repair when opening a servo motor (see Figure 6-2).


Figure 6-2 Schematic diagram of the servo motor

1 - Line socket armature 2 - connecting shaft 3 - Rotor 4 - shell 5 - Winding 6 - rear cover screw connection 7 - to install the installation of Block 1, Block 8 screw connection
9 - encoder fixed screw 10 - encoder connected to screw 11 - back 12 - rubber cap 13 - encoder shaft 14 - encoder cable 15 - encoder socket

① loose screw 6 connected to the rear cover, remove the rear cover 11.
② Remove the rubber cap 12.
③ Remove the encoder connected to screw 10, undocked from the encoder and the connection between motor shaft.
④ screw loose encoder 9, remove the encoder. Note: because of the actual encoder and motor shaft are taper engagement between, connecting to more stringent, check encoder should use specialized tools, carefully removed.
⑤ release screw connection installed Block 8, Block 7, remove the installation.
At this time, can expose the motor windings 5, after examination, found that the motor windings and pinout connections between parts of a long time because of the cooling water leakage, insulation aging; After re-connecting, processing, and then re-installed in accordance with Figure 6-2 installed on Block 7, and a fixed encoder connection screw 10, so that encoder and motor shaft meshing.
3) adjust the rotor position. Upon completion of the repair servo motor, the encoder in order to ensure that the installation is correct, then the rotor position to carry out the inspection and adjustment, as follows:
① the motor armature lines V, W phase (plugs armature B, C foot) connected.
② the U phase (armature A pin plugs) and DC voltage regulator of the "+" Union, V, W and DC voltage regulator of the "-" joint (see Figure 6-3a), encoder add +5 V power supply (encoder plug J, N interpeduncular).
③ through the voltage regulator on the motor armature current excitation add. At this time, because Iu = Iv + Iw, and Iv = Iw, in fact equivalent to the motor in Figure 6-3b as shown in the 90o position, so servo motor (permanent magnet) will be automatically transferred to U-phase position positioning. Note: the excitation current can not add too much, as long as the motor can be targeted to ensure that you (the actual repair, adjust in 3 ~ 5A).
④ At the completion of U-phase motor positioning, the rotary encoder to encoder rotor position detection signals C1, C2, C4, C8 (encoder plug C, P, L, M feet) at the same time as "one" so that the rotor motor position detection signal and the physical location of the same;
⑤ installed encoder fixed screws, fitted with rear cover, complete motor repair.
After more than repair, machine tools restored to normal.


Figure 6-3 Schematic diagram of rotor position adjust
Experience in repair and maintenance of the main points:
CNC machine tools in the repair process, sometimes encountered in some of the more specific fault, such as: Some tools in just machines, systems, and machine working properly, but when the job after a period of time, there will be a failure. Some of this failure to clear through the shutdown, the machine can then re-work; have to go through a longer shutdown time, so that machine, "rest" for some time to re-machine job. Such failure is often referred to as "soft failures."
"Soft failure" repair of CNC machine tool repair is usually the most difficult one to solve the problem. Fault because of the uncertainty and randomness of failures, making good and bad when the machine tool, which give the inspection, measurement caused considerable difficulties. Maintenance personnel must have a higher business level and a wealth of practical experience, a careful analysis of failure phenomena in order to determine the cause of the malfunction, and to solve them.
For a "soft fault" of the repair, when conditions permit, use the "swap method" can quickly determine where the fault, and under the principle of the analysis are the fundamental way to solve the problem. Maintenance personnel should be based on the actual situation, a careful analysis of failure phenomena in order to determine the cause of the malfunction, and to solve them.

Example 232. Small-scale mobile normal, large-scale movement of the fault vibration radical repair

Fault phenomenon: a used CNC FANUC 0T CNC lathes, after boot, as long as the Z-axis mobile one, there intense oscillation, CNC no alarm, machine tools not work correctly.
Analysis and treatment process: After careful observation, inspection, found that the machine's Z axis in a small area (about 2.5mm or less) mobile when working properly, smooth no vibration exercise: But more than once over the scope of machine tools that intense vibration happen.
According to analysis of this phenomenon, the system as well as the position control servo drive itself should be no failure, the preliminary judge in the position detection device failure, that is, the pulse encoder.
Taking into account the machine tool for the semi-closed-loop structure, through the replacement of motor repair carried out to confirm, to determine the cause of the malfunction was due to the negative pulse encoder caused.
To better understand the root causes of failures caused by maintenance when the pilot made the following analysis:
1) in the servo drive off the main circuit, the manually rotate the motor shaft, check the system display is found that the motor is transferred, reverse, the system will be able to display the correct value shows the actual location, indicating the location of encoder A, B, * A, * B signal output correctly.
2) because of the machine Z-axis leadscrew pitch 5mm, so long as the Z-axis movement which happened around 2mm vibration, therefore, the cause of the malfunction may be related to the actual motor position, namely, pulse encoder rotor position detection signals C1, C2, C4 , C8 signal undesirable existence.
Based on the above analysis, taking into account the Z-axis movement can be normal around 2.5mm, which is equivalent to the actual motor rotation 180o, therefore, to further determine the fault location are rotor position detection signal of C8 undesirable existence.
Example in accordance with the same method, remove the pulse encoder, in accordance with encoder connection requests (see Table 6-1), in the pin-N / T, J / K on add DC5V, the rotary encoder shaft, using a multimeter Measurement of C1, C2, C4, C8, found no change in the status of C8 confirmed encoder rotor position detection signal C8 fault exist.

Table 6-1 encoder pin connection table
Pin A B C D E F G H J / K L M N / T P R S
Signal AB C1 * A * BZ * Z shield +5 V C4 C8 0V C2 OH1 OH2

Further inspection found that the internal encoder C8 output driver IC has been damaged; replacement integrated circuit, the re-install the encoder, and the same method of Example adjust rotor angle, the machine back to normal.

Example 233. After boot cyclical vibration alarm repair

Fault phenomenon: Units 1 matching FANUC llM processing centers, boot-up, CRT display No. SV008 alarm, Z-axis vibration cyclical happen.
Analysis and treatment process: FANUC llM alarm system in the SV008 is the meaning of "stop axis error is too large", thus causing the possible reasons for this alarm are:
1) system, position control parameters are set incorrectly.
2) servo system mechanical failure.
3) power supply voltage abnormality.
4) motor and tachometer generator, encoder and other components to connect non-performing.
Based on the above possible causes, combined with the Z axis for a cyclical phenomenon of vibration analysis, and undocked from the motor and lead screw connection test, a preliminary to determine the cause of the malfunction in the electrical servo drive system parts.
In order to further determine the cause of the malfunction, repair replace the X, Z axis servo motor, to test and found the same fault, which determine the cause of the malfunction is not servo motor.
Because of X, Y, Z servo drive control panel specifications, change settings, then the short side, the replacement control panel test to prove that the cause of the malfunction in the driver control panel.
After the replacement of the drive control panel, troubleshooting, machine tools back to normal.

Example 234. Arising in the course of exercise vibration fault repair

Fault phenomenon: Units 1 FANUC 11ME matching system processing center, in the long-term use, X-axis for positive occurs when vibration exercise.
Analysis and treatment process: servo-feed system to produce vibration, crawling main reasons are as follows:
1) mechanical parts of the installation, adjust non-performing.
2) The servo motor or the speed, position detection parts bad.
3) driver settings and adjust improper.
4) external interference, grounding, shielding bad, and so on.
In order to distinguish the fault position, taking into account the machine tool servo system for the semi-closed-loop structure, was torn off and the motor and lead screw connections boot again after testing, found fault still exists, so to determine the initial cause of the malfunction in the electrical servo drive system parts.
In order to further determine the cause of the malfunction, repair replace the X, Y axis servo motor, to test and found that failover to the Y-axis, thus to determine the cause of the malfunction because of X-axis motor are caused by bad.
Oscilloscope measurement of the use of Built-in servo motor encoder signal, and ultimately found that the failure was because of bad encoder caused; replacement encoder, the machine to resume normal work.

Example 235. After the motors have a boot failure screaming repair

Fault phenomenon: Units 1 matching system FANUC 15MA CNC gantry machining center, in the start-up completed after entering the operational state, X-axis as long as the one sport that is high frequency oscillation, motor screaming generated, the system without any warning.
Analysis and treatment process: after the failure to observe the X-axis extension units, the actual extension units found a small vibration displacement; but touch motor output shaft, the rotor can be felt in a very small range, high frequency vibration: vibration and from the noise on the X axis servo motor.
Taking into account the vibration whether it is in motion or stationary when happened, the speed has nothing to do with sports, it can basically rule out the possibility tachogenerator, position feedback encoder, such as the possibility of hardware damage.
Analysis of possible causes are CNC servo drives with the relevant parameter settings, adjust inappropriate: because of machine tool vibration frequency and high time constant smaller current loop more likely to cause vibration.
FANUC 15MA numerical control system because of using digital servo, servo parameters can be adjusted directly through the system, out of repair when the servo page adjust parameters and machine random data provided by the control parameter table and found that the parameters PRMl852, PRMl825 and provide value does not match the settings below:
Parameters of the normal No. practical settings
1852 1000 3414
1825 2000 2770
To re-amend the above-mentioned parameters, the vibration phenomenon of the disappearance of, machine tools to resume normal operation.

Example 236. Ready to drive without the fault signal repair

Fault phenomenon: Units 1 matching system FANUC 0M machining center, machine tools, after starting in the automatic mode to run under, CRT display 401 of the police. Analysis and treatment process: FANUC OM appeared alarm No. 401 is the meaning of "axis servo drive VRDY signal disconnect, that is not ready to drive."
According to the meaning of failure and the machine tool servo feed system actual configuration, maintenance in the following order to carry out an inspection and confirmation:
1) check the L / M / N axis servo drives and found that the status of the drive indicator light PRDY, VRDY not bright.
2) Check the power servo drives ACl00V, ACl8V were normal.
3) Measurement of the drive control board auxiliary control voltage and found that ± 24V, ± 15V abnormal.
Based on the above checks, you can determine the initial failure of the control power driver related.
Double-check the input power and found that X-axis servo-drive input power fuse resistance is greater than 2MΩ, far in excess of the value. After the replacement of the fuse again after measuring DC auxiliary voltage, ± 24V, ± 15V back to normal, the status indicator light PRDY, VRDY have returned to normal, re-run machine tools, the disappearance of 401 alarms.

Example 237. TG servo drive fault alarm repair

Fault phenomenon: a matching system FANUC PM0 CNC lathe, in the processing time to time ALM401 No. recurring alarm.
Analysis and treatment process: FANUC PM0 alarm system ALM401 is the meaning of "Servo Driver's' ready '(DRDY) signal disconnect", drive through the inspection, you can know the reasons are servo drives TG alarm. Because of this failure to happen from time to time, you can consider unreliable cable connection failures are caused by one of the reasons why.
Re-connect the drive cables and shielding lines, grounding line, fault will not recur.

Example 238. Servo drive repair alarm HC

Fault phenomenon: Units 1 CNC FANUC l5MA supporting the gantry machining center, boot connected to one Y-axis servo, the system appeared in over-current alarm (alarm SV003).
Analysis and treatment process: FANUC l5MA alarm system SV003 content "YAXIS EXCESS CURRENT IN SERVO". Check the X, Y, Z servo drives the state of the instructions and found that Y-axis servo drive over-current alarm lights HC (red) light, direction Y Servo drives DC bus over-current existence.
This chapter, we can see from the foregoing, FANUC AC Servo DC bus through the DS will be three-phase bridge rectifier R, S, T three-phase alternating current into a DC rectifier, after filtering capacitor C as the inverter circuit inverter power source. Therefore, the reasons for failure may have:
1) The control panel of DC bus current detection aspect (such as: sampling resistor R1), the adverse feedback aspect.
2) inverse of the power transistor circuit damage.
Through the use of online tester, at the same time Y-axis drive control panel and control panel Z-axis drive signal comparison and found that Y-axis drive control panel has two thick-film integrated circuits (model DV47HA6640) damage, so that the same phase of the two At the same time, high-power transistor turn-on, causing the DC bus short-circuit. Replacement of two damaged after the thick-film integrated circuits DV47HA6640, troubleshooting.

Example 239. α Servo drive alarm "8" Fault repair

Fault phenomenon: the use of FANUC-0M CNC vertical machining center, during processing, there ALM414 alarm, α Servo Driver display alarm "8."
Analysis and treatment process: the machine tool are used FANUCα series digital servo drive system, the control section 5.2.2 of this book, we can see that the meaning of alarm system ALM414 for "X-axis digital servo system error." α drives show "8", said L-axis (in the machine tool for the X-axis) over-current.
Display content according to the police, through the machine self-diagnostic features, diagnosis parameters DGN 720, found its first four as "one", that is, X axis, there were current (HCAL) alarm.
According to Chapter 5 above, FANUC Digital Servo X-axis generated alarm HCAL main reasons are:
1) X-axis servo motor armature line error.
2) Servo Driver internal damage to the transistor module.
3) X-axis servo motor windings internal short circuit.
4) Servo Driver PCB damage to the motherboard.
According to fault conditions, because of the failure of the former machine tool can be a normal job, it can be excluded from the basic X-axis servo motor connected to the possibility of error.
Measurement of X-axis servo motor armature windings and found the same three-phase winding resistance, resistance in the normal range, and would thus be excluded from internal short-circuit the motor windings reasons.
Servo Driver internal inspection of the transistor modules, power supply with multimeter measured input resistance and white only 6Ω, lower than normal. Therefore, we can determine the initial internal drive transistor module damage.
After careful inspection of the transistor module has been damaged; replacement of one transistor module, troubleshooting.

Example 240. Fault phenomenon: FANUC 0i a matching system, αi series servo-driven vertical CNC milling machine, in the automatic processing of sudden ALM414, ALM411 alarm.
Analysis and treatment process: FANUC 0i happen ALM411 alarm system is the meaning of "moving the location of bad times too large"; ALM414 is the meaning of the "digital servo alarm (Z-Axis DETECTION SYSTEM ERROR)".
Check the Z drive show "8", indicating that Z-axis IPM alarm, possible causes are Z-axis over-current, overheating or IPM control voltage is too low. Use of system diagnostic parameters DGN200 examination revealed DGN200 bit5 = "1", show that the Z-axis drive over-current alarm.
Based on the above diagnosis, inspection, can be initially confirmed the cause of the malfunction in the Z-axis over-current. Taking into account the machine tool servo feed system for the semi-closed-loop structure, when the repair was torn off and the motor and lead screw coupling between manually rotating screw, found that the shaft is very difficult exercise, which confirmed the cause of the malfunction in the mechanical parts.
Further examine the mechanical parts of machine tools and found that the surface of non-Z Guide lubricants, machine lubrication system to check the quantitative sub-oil, and to confirm the quantitative sub-Oil undesirable. Replacement of quantitative sub-Oil after a longer period of time through the manual lubrication to ensure good lubrication Z Guide again boot test, the police disappeared, machine to resume normal work.

Example 241. Drive at the same time, OV, TG alarm fault repair

Fault phenomenon: Units 1 matching FANUC 0TE-A2 system CNC Lathe, X-axis movement when alarm ALM401.
Analysis and treatment process: check the alarm when the X-axis servo drive indicator light does not shine PRDY board, OV, TG two alarm indicator light at the same time, CRT display alarm No. ALM401. NC re-start after power outages, according to X-axis positive / negative to the sport button, table sports, but about 2 ~ 3s, there is No. ALM401 alarm, alarm drive unchanged.
Because each boot-up, CRT without warning, and the table can exercise, in general, NC with the servo system should be working properly, fault reasons are many servo system because of overload.
In order to determine the fault position, taking into account the machine tool for the semi-closed-loop structure, when the first repair was torn off and the motor and lead screw between the tooth synchronous belt, check the X-axis mechanical transmission, hand turn round belt and X-axis lead screw, Tool up and down the smooth normal exercise to confirm the normal mechanical transmission system.
Check the servo motor insulation, electrical cables, plugs were normal. But ammeter measuring X-axis servo motor current and found that X-axis static, the current value in the range of 6 ~ 1lA changes. Due to X-axis servo motor for A06B-0512-B205-type motors, the rated current of 6.8A, in normal circumstances, its no-load current can not be greater than 6A, to determine possible causes are motor brake is not released.
Further examine the brake power, brake DC90V input found "0", double-check the fuse block and found the nut loose connection off, resulting in brake should not let go. Reconnect after the brake power supply has been confirmed to join; boot troubleshooting.

Example 242. Drive at the same time, TG, DC alarm fault repair

Fault phenomenon: a second-hand matching FANUC 0M CNC milling machine, using three-axis FANUC S series servo drive one size, boot time, the drive at the same time, L / M / N axis TG, DC alarm.
Analysis and treatment process: FANUC S Series digital servo alarm occurred TG is the meaning of "break the speed control unit, namely, servo motor or encoder connection bad or speed control unit configuration error." DC alarm is the meaning of "over-voltage DC bus," possible causes of the chopper has DC bus tubes, brake resistors, such as non-performing components, or incorrect, such as system power.
Because of machine tools for second-hand equipment, double-check the drive with the line X, Y, Z axis servo motor connection, not found disconnected; check drives main circuit input voltage is correct, the DC bus voltage DC260V, and machine tool X, Y, Z axis has not been working. Based on the above inspection, to determine the basic alarm and the actual external drive unrelated to working conditions, alarm because of the drive itself are the reasons.
Taking into account the machine tool for second-hand equipment, the boot has been a long time ago not to use, the use of observation, drive carefully examined the various components and found that drive fuse FU2 (2A) has been fused; the replacement fuse with the specifications, the re-boot , the drive to eliminate the police, failure to be excluded.

Example 243. Can heat a small amount of exercise and motor fault repair

Fault phenomenon: a second-hand matching FANUC 0M CNC milling machine, using three-axis FANUC S series servo drives one body, after boot, X, Y-axis normal job, but the manual Z-axis movement and found a lesser extent, Z-axis can exercise, but continue to move Z-axis, servo alarm system.
Analysis and treatment process: According to the phenomenon of failure to check the actual work of the machine and found that after the Z-axis can boot a small amount of exercise, a rapid increase in temperature near the surface hot.
Analysis of failures caused by the above reason may be that the machine electrical control system failure or mechanical transmission of non-performing. In order to determine the fault position, taking into account the machine tool are used in semi-closed-loop structure, when the first release of the repair servo motor and lead screw connections, and re-boot test, found the same fault phenomenon, it confirmed that the police are because of the electrical control system caused by bad.
Because Z-axis machine tool servo motor with brake, brake boot after the measurement of input voltage to normal, in the system, the drive off the case, add a separate power supply for brake testing, manual Z-axis rotation and found that brake has been released, hand moving to the motor shaft smooth and easy to prove that a good brake job.
In order to further narrow the fault position, Z-axis servo motor to confirm the work of repair, using the same specifications of the X-axis motor in the machine side of a swap test, found that the motor replaced fever same phenomenon, and work breakdown phenomenon changed, thus excluding the servo motor own reasons.
Drive in order to confirm the work of repair at the drive side of the X, Z-axis drive for the swap test, namely: the X and Z axis drive servo motor connection, Z-axis drive motor connected with the X-axis. Found by the test failover to the X axis, Z axis normal job.
Based on the above tests, can confirm the following points:
1) machine tool mechanical transmission system to normal, a good brake job.
2) CNC system working properly; because when the Z axis with X axis drive motor, the machine without warning.
3) Z-axis servo motor normal job; because it is in the machine side and the X-axis motor swap, the normal job.
4) Z-axis drive working properly: Since the adoption of X drive (no fault) in the lateral exchange of electric counters, control Z-axis motor, the same failure.
Taking all these judgments can confirm that the failure was because of Z-axis servo motor caused by the cable connection.
Servo motor double-check the cable connection and found that the machine at the factory motor armature wire connection error, namely: drive L / M / N terminal is not with the motor plugs A / B / C to connect end-one mapping, phase sequence existence error: reconnect after the fault disappears, Z-axis can be a normal job.

Example 244 ~ 245. Processing overheat alarm fault repair

Example 244. Fault phenomenon: a matching system FANUC 0T MATE CNC lathe, in the processing process, often servo motor overheating alarm.
Analysis and treatment process: the machine tool servo drives are used FANUC S series servo drive, when the alarm when the servo motor touch temperature in the normal range, the actual motor without too familiar phenomenon. Therefore cause failure should be the temperature of servo drive fault detection circuit or overheating Detect bad thermistor.
Shorted through servo motor overheating detection thermistor contact again boot processing tests, by the long-running, fault disappeared, proof motors are overheating because of bad thermistor Detect overheating caused the replacement of components in the absence of conditions, can be temporarily shorted its contact to the system work properly.

Example 245. Fault phenomenon: a matching system FANUC 0T MATE CNC lathe, in the processing process, often X-axis servo motor overheating alarm.
Analysis and treatment process: the process of failure analysis Ibid cases, by checking the appearance of X-axis servo motor temperature too high, overheating in fact exist.
Measurement servo motor no-load current job and found that its value exceeds the normal range. Measurement of the armature winding resistance, discovered partial A relatively short-circuit; disassemble motor examination showed motor protection because of improper processing when coolant into the motor, the motor around the resistance-to-ground short circuit. Repair of electric motors, the machine back to normal.

Example 246. OVC drive failure alarm repair

Fault phenomenon: a matching FANUC 0T-C system, the use of FANUC S series servo-driven CNC lathe, manual sport X-axis, the servo motor does not turn, the system shows ALM414 alarm.
Analysis and treatment process: FANUC 0T-C appears ALM 414 alarm is the meaning of "X-axis digital servo alarm", by examining the system diagnostic parameters DGN720 ~ 723, found one of DGN720 bit5 = l, it can determine the cause of the malfunction of the machine tools are X-axis OVC (over-current) report to the police.
Analysis resulted in a lot of failure, but the most common repair servo motor brakes are not loose.
In this machine, because of the use of oblique bed layout, so the X-axis servo motor with a brake to prevent the decline in the blackout. After inspection, the machine failure is not brake release: Based on schematic diagram and system diagnostic signals in the state of analysis, the failure was because of bad contact between the relay caused by the replacement of the relay after the machine back to normal.

Example 247-Example 248. Parameter setting error caused by fault repair

Example 247. Fault phenomenon: FANUC 0TD a matching system of second-hand CNC lathe, FANUC matching sub-α Series Digital Servo, after boot, the system shows ALM417, 427 alarm.
Analysis and treatment process: FANUC 0TD appear ALM 417,427 alarm is the meaning of the "digital servo parameters are set incorrectly."
Because of machine tools for second-hand equipment, system debugging and found the battery has been lost, therefore, the system's parameters are to varying degrees, there is an error. Further inspection system motherboards, found on the motherboard alarm indicator light L1, L2-liang, the drive displays "-", indicating that the drive is not ready.
According to the system alarm ALM417, 427 can confirm that the alarm caused by the possible reasons are:
1) motor model parameters 8 * 20 are set incorrectly.
2) the shifting parameters of the motor 8 * 22 are set incorrectly.
3) the speed of the feedback pulse parameters 8 * 23 are set incorrectly.
4) position feedback pulse parameters 8 * 24 are set incorrectly.
5) resolution of position feedback pulses PRM037bit7 set an error, and so on.
Through the Digital Servo Settings page, in the correct parameters set above, as well as system PRM900 ~ PRM919 parameters, through digital servo initialization operation, the police disappear, the alarm indicator light on the motherboard L1, L2 out, the drive shows "0" , indicating that the drive is ready, the troubleshooting.

Example 248. Fault phenomenon: Units 1 FANUC 0TD matching αC servo drive system of second-hand CNC lathe, after booting the system shows ALM401 alarm.
Analysis and treatment process: FANUC 0TD system is due to report to the police ALM401 drive not ready, (DRDY) signal is not connected.
Check the drive status and found that 7 digital tube display as "1", meaning that the drive is not ready. Because of machine tools for second-hand equipment, downtime has been long, and after changing hands many times, therefore, the possibility of loss of system parameters larger.
Maintenance, by examining the use of electrical machine models, encoder type, screw pitch and the reduction ratio and other related parameters, the re-digital servo system initialization processing (initialization method see Chapter 5, paragraph section 5.2.6), the start-up machine, the drive shows "0", CNC alarm disappeared, through the operation of testing, machine tool X, Z axis can be a normal job.

Example 249-Example 250. Workpiece size appears erratic changes in the fault repair

Example 249. Fault phenomenon: a matching FANUCPM0 CNC lathes, in the course of their work and found that X-workpiece size appears to irregular changes.
Analysis and treatment process: CNC machine tool processing size instability usually associated with the installation of mechanical transmission system, connecting with accuracy, as well as servo feed system settings associated with the adjustment. In the machine tool using the dial indicator carefully measuring X-axis positioning accuracy and found that moving a pitch of each screw, X to the actual size is always to increase the scores of microns, and continue to accumulate this error.
Based on the above analysis of the phenomenon, the cause of the malfunction and the system seems to "gear ratio", a reference counter capacity, the number of encoder pulse parameters such as set, but after inspection, the above parameter settings are correct, rule out the improper parameter settings cause failure.
In order to further determine the fault location, repair removed when X-axis servo motor and the motor shaft through the dash mark, using manual feed incremental move in X axis, examination revealed that X-axis for each incremental movement of a pitch when the motor shaft rotation are greater than 360o.
At the same time, more than found during Detected per servo motor rotation to a fixed point of view when the "snap back" phenomenon, and in the absence of "snap back" regional, sports and motor shaft turned away from the point of view of the basic line (not exact measurements, to rely on observation to determine).
Based on the above test can determine the fault is due to X-axis position detection system caused by non-performing, taking into account the "snap back" only produce a fixed point of view, and in the absence of "snap back" regional, sports and motor shaft turned away from the the perspective of the basic line. Therefore, we can further confirm the fault and the measurement system cable connection, the system interface circuit has nothing to do, the reasons are bad encoder itself.
Through the replacement of encoder test, to confirm because of the failure was caused by bad encoder to replace the encoder, the machine back to normal.

Example 250. Fault phenomenon: a matching system FANUC 0T CNC lathe, in the job operation, the processing parts of the Z-axis size became smaller, and each change of cutting force and machine tool-related, when the cutting force increases, changes in the volume of will also become larger.
Analysis and treatment process: According to analysis of failure phenomena, resulting in failure in servo motor and ball screw mechanical connection between the. Because of the machine tool used are directly connected to the coupling structure of the form, when the servo motor and ball screw flexible coupling between the failure to lock, the screw and the motor will have a relative slip between, resulting in Z-axis Feed size became smaller.
Can not solve the coupling method of locking the normal cone sets are pressed to increase the friction. If the coupling with the screw, between the motor with the poor to rely on the coupling itself can not guarantee that the locking screw locking, the usual solution is to group sets of cone-shaped flexible in an open one of about a 0.5mm the slit to increase flexibility in sets of cone-shaped volume contraction, so that can be solved with the screw coupling, between the tie in with the bad motor caused by loosening.

Example 251. Actual mobile volume does not match with the theoretical value of the fault repair

Fault phenomenon: a package of CNC Lathe FANUC 0T, the user during processing and found that X, Z axis movement of the actual size does not match with the theoretical value.
Analysis and treatment process: because of the machine tool X, Z-axis normal job, failure is only the movement of the actual value does not match with the theoretical value, it can determine the machine tool system, the drive components, such as no fault, the cause of the problem is caused by mechanical transmission system parameters and control system parameters to match misconduct.
Mechanical drive system and control system to match the parameters in different systems vary, usually have electronic gear ratio, instructions multiplying factor, multiplying Detect coefficient, encoder pulses, such as screw pitch. The above parameters must be set in order to guarantee the system's instructions and the actual value of the mobile value.
In this machine, the system settings by examining the parameters of discovery, X, Z-axis servo motor encoder pulse number of system settings inconsistent. In the machine, X, Z axis motor model, but the contents were encoder pulses per revolution of 2000 and 2500 pulses, and the system settings just the opposite of that.
It is understood that the cause of the malfunction during the machine tool users are overhaul, the once removed X, Z-axis servo motor to clean up, but the installation did not notice the difference between encoders, thus giving rise to the above questions. On X, Z motor exchange, the machine to resume normal work.

Example 252. FANUC 0TD alarm system repair ALM416

Fault phenomenon: Units 1 FANUC 0TD matching αC servo drive system of second-hand CNC lathe, after booting the system shows ALM401, ALM416 alarm.
Analysis and treatment process: FANUC 0TD alarm system ALM401 with the meaning of the foregoing, ALM416 alarm is the meaning of "non-performing position measurement system."
Inspection system diagnostic parameters, DGN202 bit4 = l, to prove the cause of the malfunction are motor Built-in serial pulse encoder disconnected.
According to the police prompted to check X, Z-axis encoder connecting cable and found that X-axis position encoder cable disconnected part of existence.
Re-connect, the replacement of encoder cable, the police ruled out, machine X, Z-axis normal job.

Example 253. SV023 happen FANUCll alarm system repair

Fault phenomenon: Units 1 FANUC llM system supporting the processing center, the boot when the alarm happened SV023 and SV009.
Analysis and treatment process: FANUC llM happen SV023 is the meaning of alarm "Servo drive system overload", SV009 is the meaning of alarm "in the mobile process, the position error to follow the ultra-poor." In these two alarms, such as happened SV023 driver alarm, it will surely give rise to stop drives, resulting in alarm SV009. Therefore, SV023 is the main reason for the machine tool failure. SV023 generated alarm possible reasons are:
1) motor load too.
2) speed control unit on the hot relay action.
3) transformer thermal servo switch action.
4) drive renewable energy excessive feedback.
5) speed control unit adjust the settings wrong or improper.
For the above fault, you can check the adoption of the following methods, identify:
1) motor load too: in the machine run-time, by measuring the electrical current, to determine whether it is over rated.
2) speed control unit on the hot relay actions: can be hot by checking the current relay settings is less than motor rated current, and to observe the hot action to determine whether the relay.
3) transformer thermal servo switch actions: touching the transformer can be carried out to determine the surface temperature. Transformer such as the surface temperature is below 60oC, the thermal switch action, then this switch bad; otherwise, belong to the overheated transformer.
4) renewable sources of feedback can be excessive: You can check the motor increases, minus the frequency is too high: vertical axis, such as the balance is appropriate.
5) speed control unit adjust the settings wrong or improper: You can set the client by checking the signal waveform, such as dynamic to confirm.
Based on the above analysis, the tested machine motor when transported by air currents and found that the current value has exceeded the motor rated current. Servo motor will be removed after the non-electric motor, the hand rotation motor output shaft and found that the rotation axis difficult. Because of the motor without brake, therefore, can determine the motor exist problem, after further inspection found that the motor output shaft bearings damaged machine back to normal after the repair.

Example 254. FANUC l5 occasional SV013 alarm system maintenance

Fault phenomenon: Units 1 matching system FANUC 15MA CNC gantry machining center, in the normal process, the system SV013 occasional alarm.
Analysis and treatment process: FANUC 15MA system alarm SV013 is the meaning of "Y-axis servo-drive V-READY signal disconnected (YAXIS IMPROPER V-READY OFF)". Check the servo drive and found that Y-axis servo drive VRDY on the light-emitting diode does not shine.
Because FANUC AC servo-driven VRDY signal in the servo drives are the main contactor pull-MCC, servo drives connected to the main loop, the job such as a normal drive (ie drive without over-current, over-voltage, overheating, gun alarm feedback) , MCC to maintain pull-in, signal VRDY as "1."
The substance of this failure are the main contactor normal pull-MCC failed to maintain contact or poor contact, the foregoing in accordance with this chapter, and its possible causes are:
1) Servo drive failure.
2) drive back to passing the main current.
3) CNC and servo unit of the cable connection between the non-performing.
Double-check the Y-axis servo drive, found drivers VRDY In addition to light-emitting diode does not shine, no other warning lights, which can be excluded from the initial drive current passing through the main reason for return. Check the CNC and servo drives connected between the cable and found no connection problems.
In order to further determine the cause of the malfunction, repair will be Y-axis and Z axis servo drive control panel to carry out the exchange, but the fault still exists, the drive control panel ruled out the reasons for non-performing. Then, they exchanged Y-axis and Z axis servo drive amplifier board, the exchange after the failure from the Y-axis to the Z axis, thus to determine the cause of the malfunction in the Y-axis servo drive amplifier board.
FANUC AC servo control circuit to conduct a detailed inspection, confirmed the main circuit of electrical components had no failures, the resulting inference may have problems MCC contactors are undesirable in itself. In order to confirm, through an external power supply when repair directly to the MCC contactor coil 110V AC control voltage increases, the pilot found that MCC automatically disconnected phenomena exist that MCC contactor coil failures exist.
Replacement of contactors, the machine back to normal.

Example 255. FANUC l6 system ALM411, ALM414 alarm repair

Fault phenomenon: a matching system FANUC l6 import Horizontal Machining Center, in the B-axis rotation when ALM414, ALM411 alarm.
Analysis and treatment process: FANUC 16 happened ALM411 alarm system is the meaning of "moving the location of bad times too large"; ALM414 is the meaning of the "digital servo alarm (B-Axis DETECTION SYSTEM ERROR)".
The B-axis machine tool rotary table, after the diagnosis, inspection, confirmed the cause of the malfunction for the B-axis over-current.
Carefully observe the B-axis machine tool fault phenomenon and found that B-axis in a lift after the beginning of rotation, the two movements almost no pause between the process, therefore, analyze the cause of the malfunction may be due to the B-axis is not in place caused by lifting.
Given the machine hydraulic system pressure has reached the specified value, and B-axis lift switch adjust the installation location is not convenient, through the PMC procedure examination found that the signal is lifted PMC process of implementation through the delay. To this end, first of all by extending the delay time, carried out further tests.
Through the test, concluded that when the delay time after the lengthening, B-axis can be completely lifted the state of arrival, combined with the efficiency and reliability of the factors to consider, and ultimately will be changed to 1s delay after the original 0.5s, troubleshooting, machine tools back to normal .

Example 256. FANUC 16 alarm system repair ALM410

Fault phenomenon: Units 1 matching system FANUC l6 Horizontal Machining Center, CNC Department appears after boot ALM410 (Z axis) report to the police, not the normal start-up machine.
Analysis and treatment process: FANUC 16 system ALM410 is the meaning of "stop the arbitrary axis to follow the error tolerance." Cause the system to which the more reason for alarm, such as motor electrode phase sequence is incorrect, bad connections, such as encoder.
In this machine, because of failure before the machine working properly, it can basically rule out the causes of motor phase sequence to check the drive and motor connections are correct, plug fixed well, ruled out the connection may have reason for alarm.
Further observation of the actual machine tool fault phenomenon and found that when the machine boot without alarm, but once the Y-axis brake release, the spindle box that has more obvious whereabouts immediately appear CNC alarm. In view of the above phenomena, when the repair under the Y-axis machine tools are used in the hydraulic system is characterized by balance, combined with Y-axis spindle box in existence since the drop after the release of the phenomenon, a preliminary judge, alarm system and the hydraulic balance.
In order to verify, in the lower part of spindle box of wood with local support, and a small amount of space left after the start-up hydraulic system, and manually release the Y brake after a mandatory trial found that once the Y brake was loosened, the spindle box immediately the whereabouts and location Get support.
However, in the Y-axis has been supported by circumstances, the re-start machine, the system without warning, Y-axis can also be a normal job, which confirmed that the failure was because of Y-axis caused by an adverse balance system. Hydraulic balance of system maintenance, adjustment, the fault disappears, machine tools resume normal job.

Example 257. FANUC l6B alarm system repair ALM414

Fault phenomenon: Units 1 matching system FANUC l6B, α Series Servo-driven horizontal machining center in users drives damaged, re-replacement of Y-axis drive, the boot after moving Y-axis when ALM414 alarm.
Analysis and treatment process: FANUC l6B appear ALM414 alarm is the meaning of the "digital servo alarm," the cause of the malfunction diagnosis of the parameters can DGN200 ~ DGN204 be checked.
Inspection found that the machine DGN200 bit2 = "1", indicates that the existence of non-performing regenerative braking circuit, and further checks the drive, its status appears as "4",? Show that the regenerative braking circuit alarm exist.
Taking into account the replacement drive is a brand-new spare parts, according to the scene learned that the replacement drive has been confirmed before the Y-axis motor, connect the cable there was no anomaly, the above analysis, a preliminary to determine the cause of the malfunction drives are caused by incorrect settings.
By examining the actual machine tool control system electrical design, confirm that the axis of the external drive to use the regenerative braking resistor 200W. Therefore, the driver must set the corresponding. Drive to open the front cover to check and found that the regenerative braking drive settings (S3/S4) is incorrect. After the correct settings, troubleshooting, machine tools to resume normal work.

Example 258-Example 259. FANUC l6B system ALM414, ALM411 alarm repair

Example 258. Fault phenomenon: Units 1 matching system FANUC 16B, α servo-driven vertical machining center imports, in the automatic processing process, often Y-axis ALM414, ALM411 alarm.
Analysis and treatment process: FANUC l6B system ALM414, ALM411 meaning and analysis of the process with the foregoing, through the diagnostic parameters DGN200, DGN201 inspection, appear when the alarm DGN200 bit7 = "1", DGN201 bit7 = "0", indicates that the cause of the malfunction for the Y axis motor overheating. Hand in the failure of Y-axis servo motor, sensory motor looks hot, in fact proved the existence of Y-axis motor overheating.
Because of machine tools in the boot of a certain period of time after the job properly, without warning, therefore, the initial Y-axis to determine the failure was caused by too much load.
After the shutdown, manually rotating Y-axis lead screw and found that very difficult to rotate, which confirmed the cause of the malfunction in the mechanical parts. Check repair Y-axis rail extension units and found that the machine tool bed onto chip stacking, Y-axis guideways pollution. Re-clear the iron, removed Y-axis guideways Article inlaid on the extension unit to conduct a comprehensive clean-up, maintenance, after continuous operation test, fault disappear machine to resume normal work.

Example 259. Fault phenomenon: Units 1 matching system FANUC 16B, α servo-driven vertical machining center imports, in the rotary table (A axis) rotation, the emergence of A-axis ALM414, ALM411 alarm.
Analysis and treatment process: FANUC l6B system ALM414, ALM411 meaning and analysis of the process with the foregoing, through the diagnostic parameters of inspection confirmed that the cause of the malfunction is the A-axis overload. Scene analysis, the A-axis machine tools for the rotary table, and have brought Tailstock Hydraulic fixture, causing A-axis may be caused by overload and the turret with the release of the release Tailstock relevant action. In order to determine the fault position, in the repair process, remove the hydraulic clamp, so that Tailstock turret connection was torn off and then boot test machine fault disappears, thus determining, leading to A-axis may be caused by overload and Tailstock relevant. Boot, after the release Tailstock, manual rotation rotation Tailstock found difficult to re-adjust Tailstock clamp, loose bodies, in the confirmation Tailstock reliable release, the boot test, fault disappears, machine tools back to normal.

Example 260. FANUC l6B occasional ALM414 alarm system maintenance

Fault phenomenon: Units 1 matching system FANUC l6B, α servo-driven vertical machining center imports, in the automatic processing machine, the occasional ALM414 (X Digital Servo) alarm, after rebooting machine failures can disappear.
Analysis and treatment process: FANUC 16B alarm system ALM411 meaning with the foregoing, through the diagnostic parameters confirmed that the cause of the malfunction are X-axis encoder connection bad. Because of occasional failure to analyze the possible reasons are the largest X-axis encoder connection bad.
Through the X-axis servo motor encoder checks and found that their plugs loose, re-fixed, troubleshooting, machine tools to resume normal work.




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CNC repair three-step method

1, power supply circuit
In the maintenance of power supply circuit should first check whether it is normal, and then check the other parts. Power failure has the following forms:

(1) No supply voltage or supply voltage low
CNC system often used ± 5V, ± 12V, ± 15V, ± 24V, using a small number of +3.3 V. The supply voltage is not normal, that is, the system will cause abnormal job. Of emergency equipment, causing equipment and personnel injury, must pay great attention to. Machining center, after boot without any CRT display. Detection system using a multimeter power board A14B - 0067 - B002 - 01, found +5 V power supply voltage of 3.75V, remove the load detection, +5 V power supply for the +4.95 V. Note the low power supply with load capacity or load short-circuit has existence. After checking the normal load. Note decline in power supply with load capacity. After inspection the replacement filter capacitor C36, the system work properly. Tool-free action. Turn off the power supply, power back on, machine tools can work in a period of time. Check all the normal power supply. Fault may be in the system's motherboard. After overhaul motherboard A16B-1000-0220/04A, found two crystal an internal crystal oscillator 16.3840MHz bad, have not replaced the use of the recurrence of similar failures.
(2) power supply voltage detection voltage meter to normal, but Oscillograph detected large ripple voltage waveform. Power supply filter capacitor is normally open circuit, rectifier diode caused by bad or, and sometimes are a component breakdown caused by damage to power overload.
(3) when the system just drive normal, after a period of job decline in the supply voltage. This is usually the voltage regulator circuit or high-power triode bad. In temperature caused by power supply voltage drop, or it may be a component defect, temperature after bad.
No supply voltage or supply voltage severely reduced, the system will cause the disruption or cessation of work, which was easy to detect and find fault. When the power supply capacity with load decrease or filter circuit failure, it is difficult to judge. System it will suddenly stop working, causing
If Units composed by FANUC 3MA
2, the clock circuit
The main clock circuit in the system are the motherboard, it is the large-scale integrated circuits which work in basic conditions. It is crystal oscillator (commonly known as crystal oscillator) for the foundation, in the circuit produce a constant square wave signal. Crystalloid vibration, just like people, like the cardiac arrest, allowing the system to in a paralyzed state. Crystal normal job, the system circuit can be under the command of the CPU clock by crystal beat job. Quantity and frequency of the oscillator with the CNC system vary, but generally at least one, and the remaining requirements of the different circuit clock frequency by dividing frequency of the crystal oscillator circuit or another to solve.
The higher the failure rate of crystal, and its common fault has the following categories:
(1) crystal leakage damage. Multimeter available P × 10K block measurement, if the resistance is infinite, compared with normal; if compared with leakage resistance.
(2) the internal open-circuit crystal. Measuring its resistance with a multimeter though infinite, but in the circuit should not have a pulse oscillation.
(3) crystal metamorphic change its parameters. Only by oscilloscope and frequency meter can detect. Crystal are able to oscillation, but the clock frequency from its nominal value, although the oscillation pulse at this time, but because of the number of error pulses, the system can not work the circuit. At this point only by frequency meter can be accurately measured their deviation.
(4) in the actual clock circuit, the crystal at both ends to have access to have a few to dozens of Paper Paper Act law tiles capacitance, the capacitor leakage, deterioration caused by the clock circuit fault is also more common. Detection of mixed crystal is best to use oscilloscopes and frequency of measurement, it is difficult to assess its quality multimeter.
If FANUC 6M Control Units from the machining center, working for some time, a sudden black screen CRT,
3, reset circuit
Reset circuit is also exist in the system circuit board, which is unique to large-scale digital integrated circuits circuit. Microprocessors, interface circuit and others have reset terminal.
Reset circuit reset pulse generated by the program counter cleared, so that CPU out from the memory initialization file for the control port to initialize the chip. If the reset circuit bad, the system will happen disorders, such as fault crash.
Oscilloscope observation generally reset pulse should be repeated on-off power supply, the switch connected to the instantaneous observation of each reset pulse. Reset pulse should be rectangular ideal square wave. If no reset pulse should be checked in the reset circuit resistors, capacitors, transistors and so on. IC reset the rules of client should be low or high, otherwise, should be reset circuit failure or damage to integrated circuits.
Units like the use of large-scale PLASMA CNC machining center, the system could not be activated, CRT showed no alarm. After inspection ± 5V, ± 12V, ± 24V supply voltage normal, normal clock circuit. Suspected to be the system's motherboard problem, reset circuit in the inspection, it was found that no client CPU reset reset pulse. Further examination revealed a reset terminal 3.3k/0.5W open resistance, the replacement of normal after the system restart.
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How to fix CNC machine tools, CNC repair experience

CNC machine tools are well-known contemporary high-tech machines, electricity, light, gas integration of the crystallization of complex electrical, pipe cross-proliferation of all kinds of NC system, products from the 70's to 90's, are not interchangeable, fault is the strange phenomenon, different, especially for large, heavy-duty CNC machine tools, which is very expensive, about several million dollars each, the installation time to adjust length (l a few months to over a year). Large-scale NC machine tools, there are hundreds of thousands of components, if one of has has a component failure will cause the abnormal phenomenon of machine tools, as well as wire connections, the pipe coupling with each other, it will neglect the problem, In addition, large, heavy-duty CNC machine tools are huge in size and in the absence of plants under conditions of constant temperature use, environmental impact can easily lead to failure. To this end, the NC machine tool, "difficult to repair" the problem on the U.S. before.
The introduction and manufacturing of our country for so many of CNC machine tools, how to quickly identify the failures, dangers, and promptly ruled out of? How can repair these expensive equipment? First of all, in my opinion to have a high degree of responsibility and the spirit of fearing no difficulties; Second, we must strive to master digital technology, contact my CNC machine tool repair for more than a decade of practice, in my opinion to watch many, many ask, many in mind that many thought practicing (over 5), and gradually improve their own technical standards and repair capabilities, to adapt to a variety of more complex situation, to solve difficult problems, repair of CNC machine tools.
First, it is necessary to watch many
1. To watch many of NC data
Many look to, to understand a variety of numerical control system and PLC programmable logic controller of features and functions; To learn more about CNC system alarm and troubleshooting; To learn more about NC, PLC machine parameter settings meaning; To learn more about PLC's programming language; To learn more about NC programming methods; to understand control panel operation and the contents of the menu; to understand and take the knife spindle motor drive performance and characteristics and so on, often a lot of numerical control information, look how? In my opinion we should give prominence to the main focus, to understand the origin and development, focusing on a thorough grasp of numerical control system are the basic composition and structure, master block diagram. The rest can "tour" and read, but every part of the contents must be focused on understanding, grasp. Because of numerical control system is a complex internal circuit diagram, and manufacturers do not provide. Therefore there is no need to find out in detail. Such as NX 1 154 five axis machine tools even the rotor blades using A 1 B10 system, we should focus on understanding the role of each part, the board's function, the destination interface, LED lights, such as the meaning. Now many models of CNC system, faster updates, different factories, different models often vary widely. To learn more about their similarities and individuality (uniqueness). Generally familiar with the CNC system SIEMENS repair person will not necessarily rule out the A-B skilled system failure, therefore, it is necessary to watch many, and constantly learning, updating our knowledge.
2. To watch many electrical diagram, electrical diagram digestion
For each electrical component, such as: contactors, relays, time relays, etc., as well as PLC input and output, to indicate electrical diagram 11. Let me give a simple example, such as 1A1 start for hydraulic pump motor contactor 1M generally in Fig bet its normally open, normally closed contacts of the future. Therefore, its corresponding page in a normally open or normally closed contacts 1A1, specify the content for the hydraulic pump motor to open for large-scale NC machine tool has dozens of electrical map pages, or even hundreds of pages. To understand that the function of each component should be of a very long time. Sometimes, one, the second look may also not sure the role of the components, it is necessary to watch and so many after the digestion and then write. Therefore, the startup has also mentioned that the hydraulic pump motor 1M, should also be clearly marked PLC of which are outside the output contactor Driven 1A1 action, to do the whole story, clearly. Electrical circuit diagram of some of the block diagram, such as the drive for each axis, only a block diagram, as long as the understanding of a certain control conditions (on-off situation), for detailed time and other things such as further study and consider. Individual countries are not the same as electrical symbols, they must first clearly understand. Factory prepared for the thick layer of several PLC STL, but also many look to master its programming language, in the read on the basis of Chinese Notes. This can be reduced substantially after the troubleshooting time, and if such failure happened again to become familiar with the electrical diagram, PLC STL, it is bound to cost a lot of time and often lead to wrong judgments.
3. To watch many hydraulic, pneumatic diagram, and depth of digestion
CNC machine tools for mechanical milling machine, hydraulic, pneumatic diagram, it is necessary to clarify its role and context. And 11 in the drawings indicate, such as Germany COBURG CNC gantry milling attachment, tool installation more complex, it is necessary to break down their plans, such as locking tool which moves the solenoid valve? Corresponding PLC exports, imports which are? Stated in the chart, so that the electrical to the mechanical action from the one pole in the end, while particular machines, electric part relatively close to the focus of understanding, such as Italian INNSE CNC Boring Milling Machine using electro-hydraulic proportional valve technology, we should focus on understanding its role and function, in particular, to understand and adjust adjust its data, static and dynamic when the proportional valve current and the corresponding equilibrium pressure pump, knows also understand electric machines, mechanical and electrical integration, have a variety of skills, such problem-solving skills on larger.
4. To watch many foreign languages, it is necessary to improve their professional ability of foreign language reading
Do not know foreign languages, especially English. Will not be able to read a large number of foreign technical information, simply relying on the translation, often are not very satisfactory. Watch foreign-language version of the technical information, the beginning of relatively difficult vocabulary many, many more look in mind, the commonly used word professional is the only way many future looks smooth, and a competent maintenance personnel to the basic tools to master the language.
Second, it is necessary to ask many
1. To ask many foreign experts
If you have training opportunities abroad or foreign experts to come to your factory installation and debugging tools, you'd better have the opportunity to participate. This is a best opportunity to study, because a large number of first-hand access to information and method of debugging tools and techniques. Such as in laser precision determination of the axis, the electric how to approach such an amendment. To many question, do not have to find out. Through this period of time will be of great benefit, be able to get a lot of internal information and manual (the user is confidential). When the machine into formal production, should also be frequent contacts with foreign experts maintain close ties. Through FAX, E-MALL, asked whether the problems were resolved Machine Fault further solutions and related information, can also be a special, special spare parts, which are very useful, while the CNC system agents, such as SIEMENS, FANUC, etc. Companies should also maintain good relations, many asked, could also be timely step in the numerical control system of deep information and related spare parts, also have the opportunity to participate in the NC system thematic study classes.
2. Malfunction, the master asked the operator to the failure of the entire process, and will not question, or just look like a question, so often fail to get the correct information at the scene will cause wrong judgments, so that complicating the issue, Therefore, in order to ask many, that question in detail and understand the entire process of fault occurred (beginning, middle, end), resulting in what the police number, then what components to operate, come across what to turn over what and how the external environment? To fully investigate the scene gain first-hand material on the basis of questions put fault correctly listed, in fact has solved half the problem, then analyze the solution for the experienced and skilled master operator, they are familiar with machine operator and processing procedures are familiar with, machine tools is very common understanding, close cooperation with them, for rapid troubleshooting very favorable.
3. To ask many other maintenance staff
When the other maintenance staff in the maintenance of machine tools, and you do not go when they came back, many should also ask, just what happened wrong? Is how to exclude him? Asked him to rule out the introduction of its methods. This is also a good learning opportunities. Others studying the correct troubleshooting skills and methods, in particular, to repair the old, experienced staff study,put their skills to improve their knowledge and standards.
Three, it is necessary to remember many
1. To record the various parameters)
Record machine adjust the focus after a good variety of parameters, such as NC machine tool parameters, PLC machine parameter, PLC program (more than the existence of disks), as well as the spindle and the tool motor current, voltage, speed and other data. Would also like to note the electric cabinet relays, contactors, such as in processing power and formal status (pull-in or disconnected) and the PLC for all input and output state of light-emitting diode LED (light dark, shining) or record the screen PLC state of IB (input bit), QB (output bit) is 0 or 1, such as IB1 =: 00000001, that is, I1.0 = 1, I1.1-1.7 = 0. This record for later analysis to determine the benefits of a great fault. Such as Germany SCHIESS happen CNC Vertical Lathe Z axis motor current relay action, we check the Z-axis motor normal working hours of the PLC state (0,1) and non-normal compared to the situation quickly find the cause of the malfunction, because one has Comparing the state of not only the relay, through adjustment, failure to immediately rule out the possibility.
2. To Record hydraulic, pneumatic state
Record same hydraulic, pneumatic or not in the formal processing of processing all kinds of pressure gauge, barometer pressure, the suction solenoid valve fault state, which adjust to judge is also a great help. Such as the United States keep out INGERSOLL OPENsIDE MASTERHEAD CNC milling machine hydrostatic dual-film technology, has more than 100 pressure measurement points, its high and low pressure machine features a direct impact on the normal action or not, the record of static and dynamic pressure is very important.
3. Carry a notebook, put the failures happen every day, how to exclude the process of record each and every human brain has been a long time easy to forget that "good memory, it is better written rotten," the benefits of a great record. CNC machine tools we have found some fault will often repeated, but always a few failures, as long as the check was how to resolve, and a few minutes troubleshooting, fast and good. Our company has a "running diary of CNC machine tools" and a "CNC machine tools ranked it the Record" to record information on these two, this is a CNC machine tools complete archives.
Fourth, it is necessary to think of many
1. To think of many, it is necessary to broaden our horizons
Often sometimes repair is not calm, not a good analysis, go to a dead end. COBURG remember that Y-axis gantry milling in the processing of a sudden shutdown, the screen on several occasions appeared dirty 1361Y-axis grating alarm, when we clean things Grating and grating the first 2 times and the results or downtime. Of a few days yet to be resolved, and finally found the real reason is because the Y-axis grating head to the wire between the amplifier EXE have questions, because Y-axis movement of long-term snakeskin tube bending, one of a position feedback lines well, to a certain location of the fracture caused by machine downtime. At that time, we only pay attention to static, neglecting the dynamics of 1321, there were once open-loop control police, but did not cause us enough attention. Therefore, we should put what happened alarm, fault conditions list them all, through, judge and integrated screening, prediction of the greatest possibility of failure, and then take actions to remove. "Exhausted suspect a blind alley and prospect", many think, give you a clear direction.
2. To think of many, it is necessary to know
Often when we are troubleshooting, and sometimes not find the real reasons for failure, after the failures continued to occur. Ingersoll remember to cotyledon root groove milling machine, spindle Sl happened 2 hours after the operation of "automatic stop" the failure of foreign experts at the time the order for a piece of board, seems to solve the problems, but after more than a month after they committed In other words, the order of a prepared plate or board, but did not find out the reasons for its damage. We have carefully inspected through the use of oscilloscopes and found that the "start" command the corresponding optocoupler particularly high anti-peak voltage, the addition of a separate grounding line, and its anti-optocoupler greatly reduced peak voltage, Since then, there have been no "automatic stop" failures, the reasons are because of the anti-peak voltage is too high, after a long time to optocoupler due to the gradual failure.
3. To think of many consider to be one step ahead
According to the frequency of failures happen, repeatability, life expectancy of electrical machinery, spare parts do a good job seriously. This is the machine to ensure continuous, the normal operation of an important job, non-do not. At the same time, some devices, as time delayed, eliminated, the market has been unable to buy tickets or buy very expensive, how do? Prior considerations, such as have a early 80's CNC machine tools used in photoelectric readers read with LOOP way into the processing procedures, may also use the opt-SPOOL way the original tapes (machine settings data), the event does not get sent, then the entire machines will become "dead" machine, with very serious consequences, because we are one step ahead to consider, in cooperation with relevant units, after numerous tests, using a floppy disk processor solves this problem to ensure that the machines can use so far. Many think, it is necessary to consider in advance, give leadership to rationalize the proposals, efforts to improve the external environment for CNC machine tools, from the temperature, dust, humidity, etc. want to approach several aspects, the use of retro-power voltage regulator, the installation of electric air-conditioning cabinets small house and other measures to enable the machine tool failure greatly reduced.
Friday, it is necessary to train many, that is, the practice of many:
1. To the practice of many, should have the courage to do, good hands
For maintenance personnel who will have to bold but cautious, we must dare to do, it will only talk about, not his fists, not CNC machine tool repair. However, the situation should be cooked no longer do, do not blindly, or else they will expand the fault, resulting in accidents, the consequences would be unthinkable. At the same time we still have good hands, first of all to familiar with the machine tool on the machine operation panel and the contents of the menu and do a good job operating ease, because the various models and system operation are the same. At the same time must also take full advantage of self-diagnosis of CNC machine tool technology to quickly solve the fault treatment. CNC technology is now more developed, it has since more and more consultation capacity. 1 A system such as B10, have special diagnostic software, Internet diagnostics.
2. To many practices, develop their own practical ability and mastery of experimental skills
Fault sometimes seem very vague, are hard to mechanical failure or electrical fault, such as gantry milling COBURG such a fault happened, which means that the Z-axis, whether to increase or to decrease, Z-axis ram always down and alarm. We have adopted a "separation of law", the electrical part of the control and completely separated from the original circuit, the Z-axis DC motor terminals on the line removed, and the other pass DC (220V power supply can communicate through the regulator, after four rectifier diodes give) received the electrical two-terminal and found that motor in accordance with the polarity of the DC transform change the rotation direction, remove the electrical fault, re-examination revealed that films are playing because of mechanical friction caused by ptosis pillow. There are a lot of other methods, such as "isolation method", "displacement method", "contrast", "percussion Act" and other methods can be used as an effective means to help us find and remove faults.
3. To many practice and learn the use of the device
Such as oscilloscope, multimeter, on-line detector circuit, short circuit tester, computer, programming, etc. can help us determine the specific circuit, inspection, in particular the PLC programmer, computer, it is necessary to skillfully use, be free to import, export machine parameters online test on the state, such as system initialization. This analysis of failures, especially for complex fault, has a lot to help solve the problem.
4. To many practices, the "small改小reforming"
Often happen in the normal work of a particular component damage (such as choice of switches, buttons, relays, etc.) and no spare parts, they do as far as possible, stick with the legitimate use of such means as the repair or temporary special ways in which machine tools can continue to work , to wait until after the restoration of spare parts. VDF CNC carts such as Germany's No. 2 in the Blade has five clamping pressure with micro-switch, one of two micro-switches accidentally damaged, no spare parts, we have adopted a "short connection" so that the touch pressure switch point in line with the PLC input conditions for the machine tool is not the normal work of the police can go on. Sometimes long after the use of machinery, worse positioning accuracy, positioning alarms generated in the machine tool can not re-adjust the circumstances under which a temporary amendment to machine parameters, to increase "tolerance" zone, so that it can work properly, in a word, such an approach also much.
5. To the practice of many, it is necessary to do-it-yourself repair board
CNC machine tools in general the reliability of the circuit board, and the failure rate is extremely low, go check the CNC machine tools in general, do not question the board first suspected. Such as the Siemens 850 system, sometimes 41NC-CPU alarm or 43PLC-CPU alarm, not the board has in fact a fault can be removed Stubbs Law, NC initialization methods such as hot and cold start the PLC can generally be excluded from trial and error. If indeed proved to be circuit board problem, it is necessary to make repairs. These plates (usually without the drawings) is expensive, there are generally a few thousand dollars ─ few million, for each enterprise "hard parts", the price too expensive, preparedness can not afford, so CNC machine tools is extremely good or bad circuit board important, once the circuit board without damage to spare parts, at other times, they repair bad shutdown is bound to seriously affect production. Sometimes only a very small circuit board failures, as long as careful inspection, it is not difficult to discover problems, we have repeatedly found that individual capacitor leakage, board, short-circuit fault, etc., some more complex circuit board failure, but as long as time, through inspection instruments, or be able to repaired; but there are some circuit boards in serious condition, especially the large-scale integrated circuits, maintenance difficulties, coupled with the original device no spare parts, can only be prepared in advance to buy board or send out repair. Do-It-Yourself repair board, has a great advantage, on the one hand, enterprises can reduce costs and solve the immediate needs, on the other hand, "Anatomy of Sparrows" familiar with the electronic circuit, develop their own analysis and practical ability is very useful.
Through the repair more than a decade of practice, we are foreigners designed CNC machine tools, especially large-scale NC machine tools are not perfect, there are also many problems and shortcomings. Through our study of NC machine tools, and deepen, to find out where the problem is one of boldly to improve on some issues, and achieved good results. VDF CNC carts such as Germany, the original design of two hydrostatic power bracket on one job, hydrostatic pump continuous operation, so that also charges electric pump also shortens the life span of imports. We modified PLC, an increase of two switches, only dozens of yuan, so that hydrostatic two brackets can be arbitrarily open or stopped, so that imports of extended pump life, a full year saving more than 20,000 degrees. Ingersoll Milling impeller shafts are the original design, the main head and deputy head only reverse milling, milling in the same direction without. High and medium pressure in the processing section 20 impeller rotor, the impeller because of the distance between the small and should not reverse milling, it can only be a first for processing. Through our research, subtly altering the limit two-way connection, an increase of PLC program, the result of almost no money, to achieve the same milling. 2 heads are now available at the same time processing, improve efficiency doubled, advanced 3 ─ 4 days processing rotor task. Therefore, we should further tap the potential of CNC machine tools, and better exert its power for the production of services.
Despite the numerical control machine tool fault complex, ever-changing, as long as we take seriously and cultivate a high-quality repair of mechanical and electrical integration team, look through the many, many ask, many thought, many training and accumulated experience and repair techniques, together, we must be able to rely mainly on their own strength, the CNC machine tool repair and make good use of, possession of a good.
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CNC machine tool repair technology

With the electronic technology and automation technology, NC technology more widely. To microprocessor-based, large-scale integrated circuits marked CNC equipment, has been in our production, substantial introduction and popularization and application, they give the machine manufacturing industry created conditions for development, and bring great benefits. But at the same time, because of their advanced nature, complexity, and intelligent high, in the repair theory, technology and means to have taken place on changes in leaps and bounds.
CNC repair technology is not only a prerequisite for the protection of the normal operation of CNC technology development and improvement also has played an enormous role in promoting, Therefore, at present, it has become a specialized discipline.
In addition any CNC equipment is a process control equipment, which requires real-time control in every moment of the accuracy of work. Any part of the fault and failure, it will enable the machine tool downtime, resulting in the production of a standstill. Numerical control system and thus the complexity of such a principle, structural repair sophisticated devices it is very necessary. In particular, the introduction of CNC machine tools, most of them spent hundreds of thousands to tens of millions of dollars. In many industries, these devices are at a critical job, if not a timely manner after failure troubleshooting repair, will result in greater economic losses.
We repair the existing situation and the level of imported equipment and the design and manufacture of technical level there are still a large gap. Of the underlying reasons are: poor quality of personnel, lack of analysis of digital test instruments, the number of domain-domain and frequency domain and several aspects of the integrated test and analysis techniques to be improve and so on.
Here we have a modern CNC system constitutes the basic starting point to explore the numerical control system diagnosis and repair.
One numerical control system with the characteristics of the composition
The world a wide range of CNC system, the form of different structural components have their own characteristics. These structural characteristics of the system from the initial design of the basic requirements and engineering design ideas. Points such as control systems and continuous trajectory control system there is different requirements. The T system and the M system, also have vastly different, the former applied to Rotary Parts processing, which fit in the special-shaped non-rotating body parts processing. For different manufacturers is based on the historical development of factors and vary from place to place each of the complex of factors, may also be thinking in the design is different. For example, the United States Dynapath system uses a small plate structure, easy and flexible combination of the replacement board, while Japan FANUC system tended large panel structure to facilitate the work of the system reliability to the system MTBF rates rising. In either system, however, they constitute the basic principles and are very similar. In general the entire CNC system consists of three major components, namely, control system, servo system and position measuring system. Control system for processing workpieces by computing interpolation procedures, issued instructions to the servo drive control system; servo drive control system will command magnified, by the servo motor-driven machinery required to exercise; measurement system Detect mechanical position or velocity of the exercise, and feedback to the control system, to amend the control orders. Organic combination of the three-part form the complete closed-loop control of the CNC system.
Control system mainly by bus, CPU, power supply, memory, operating panels and displays, digital control unit, programmable logic controller control unit and data input / output interface and so on. The latest generation of CNC system also includes a communication unit, it can complete the CNC, PLC's internal data communications and external high network. Servo drive systems, including servo drives and motors. Position measurement system is mainly the use of long or round grating grating incremental displacement encoder.
The main features of numerical control system are: high reliability requirements: because once the CNC system failure, that is a tremendous economic loss; has a higher ability to adapt the environment, because the general numerical control system for industrial control machine, the working environment for the workshop environment, the requirements it has in the vibration, high temperature, humidity and various industrial sources of interference conditions and the ability to work under; interface circuit complexity, numerical control system with a variety of CNC equipment and peripherals to match, it is necessary to deal with the production process at any time in various situations, to adapt to a variety of process equipment requirements, and thus the complexity of the interface circuit, and frequent job.
2 Modern numerical control system of the basic conditions for repair job
2.1 Maintenance of the basic conditions for staff
Repair work was good or bad depends on the staff first of all conditions, the maintenance staff must possess the following requirements:
(1) a high degree of responsibility and good professional ethics;
(2) broad knowledge to master computer technology, basic analog and digital circuits, automatic control and electric drag, detection techniques and aspects of the machining process knowledge and a certain basic level of foreign language proficiency;
(3) After a good technical training, information on the CNC, drive and PLC's working principle, know how to CNC programming and programming languages;
(4) are familiar with the structure, with strong experimental skills and hands-capacity;
(5) have a variety of commonly used (especially the scene) of the test apparatus, instrumentation and various tools.
2.2 means in the repair should be the conditions
(1) ready to commonly used spare parts, accessories;
(2) micro-electronic components can be the actual support or supply;
(3) the necessary repair tools, instruments, meters, cables, computer. Have the best small-scale programming system or programmer to debug support equipment;
(4) complete information, manuals, circuit diagram, maintenance instructions (including the CNC operator instructions), and the interface, adjust with the diagnosis, specification-driven, PLC specification (including the PLC user program alone), components forms.
2.3 Preparation before the repair
Receiving the user's direct request, as far as possible direct contact with the user in order to access the site information as soon as possible, on-site conditions and fault information. Such as CNC machine tool spindle drive into the given model, the police instructions or failure phenomenon, the user site, such as the availability of spare parts. Accordingly pre-analysis of the cause of the malfunction that may arise with the site, then before the departure to the scene, ready-related technical information and repair service tool, apparatus, spare parts and so on, have prepared to do away.
3-site repair
Field repair of CNC machine tool breakdown (mainly NC part) for the diagnosis, identify the fault location to the corresponding normal parts replacement, so that machine to resume normal operation. This process are the key to diagnosis, that is, the system or the external line test to determine whether the fault, and fault location pointed out that the exact location of fault. From the machine to plug line positioning plate, and in some occasions even locate components. This is a major part of the repair job.
3.1 Numerical Control System Fault Diagnosis
(1) initial identification is usually a more full-time in the data through data analysis to determine where the fault, or interface signal law judge in accordance with the phenomenon of fault location fault may occur, and then in accordance with the fault with this part of the specific characteristics of each site inspection preliminary identification. In practical applications, it may be a way to find fault and to remove, and sometimes required a number of ways and used. Point of failure for a variety of ways to determine mastery of the extent of the malfunction of equipment depends primarily on the principle and structure of the depth of grasp.
(2) report to the police report to the police deal with the treatment ① system: CNC system failure, a general in the operation panel display or give fault signal and the corresponding information. Usually manual system or adjust the manual has detailed alarm number, alarm content and methods of treatment. Because of the alarm system set up a single, complete, tight, clear and repair may be based on the back of each alarm information and give way to deal with their own treatment. ② machine alarm information and operation of the treatment: Machine Tool Machine Tool factory in accordance with the electrical characteristics of the application of PLC program will be able to reflect some of the electrical machine control interface failure or operator specific information signs, displays give through and through specific keys, see a more detailed description of the alarm. This type of alarm can be provided in accordance with werkzeugmaschinenfabrik troubleshooting manual treatment, can also use the operation panel or the programmer circuit diagram and the PLC in accordance with procedures, to identify the corresponding signal state, according to the logical relationship to identify the point of failure to deal with.
(3) No alarm or alarm failure could not deal with the PLC when the system can not run, system downtime or system has not reported to the police but is not working correctly when required in accordance with pre-and post-fault system state information, the use of the available theoretical basis for analysis , make the right judgments. Elaborated the following fault diagnosis and rule out the possibility of such approaches.
Fault diagnosis method of conventional test
Visual visual fault plate, carefully check for blown fuses, components charred, smoked, cracking phenomenon, whether or not the phenomenon of foreign body circuit. As can be judged, and whether the board over-current, over voltage, short circuit and so on.
Hand touch and components, especially the resistance-capacitance, semiconductor devices sense whether or not loose as can check out some broken legs,and so on.
Electricity first used a multimeter to check whether the circuit between the various power, such as free access to the corresponding power supply, whether visual smoke, brand and other phenomena, whether or not abnormal hand components fever, this can be found in some of the more obvious failures, and to narrow the scope of overhaul.
For example: a factory in Harbin troubleshooting, the machine tool CNC system and the PLC is running normal, but the machine's hydraulic system will not boot, and check the PLC programmer process operating normally, the signal state are required to meet the conditions of the boot. Further inspection found, PLC signal state with the drawings and equipment marking inconsistencies, parking pull-out circuit board inspection and found that PLC 2 output boards addressing wrong, wrong location and another two by the exchange after the normal operation of machine tools. For this failure happen machine used in SIMATIC S5-150K programmable controller, as long as the addressing is correct, regardless of the location of the circuit board will be how to order, the system can be normal operation, but the implementation of the corresponding components and signal source must be correctly counterparts, once the corresponding fault error occurs, and even damage machine tools. In addition, according to users fault phenomenon, combined with their own on-site observation, the use of the system working principle can also quickly make the right judgments.
Instrument measurements when the system broke down after using conventional electrical testing instruments, tools, machine tool according to the system circuit diagrams and circuit diagrams of fault part of the voltage, power supply, such as pulse signal measured to determine where fault. Such as power supply input voltage overrun, causing power supply voltage meter measurements can be used to monitor the network voltage, or voltage tester with real-time monitoring to rule out other causes. Such as position control loop fault happened oscilloscope can be used to check the signal measurement circuit state, or oscilloscope to observe the signal output phase is missing, whether or not interference. For example, a factory in Shanghai in troubleshooting, system alarm, the location of ring hardware failure, using oscilloscopes have detected interference signal, we then used in circuit capacitance method to filter out the system working correctly. Emerging systems such as the reference point is unable to return to the situation that can be used to check whether the zero marker oscilloscope pulse, could be considered if there is no measurement system are damaged.
PLC controller with programmable interrupt state analysis: programmable logic controller failure, the reasons for their interruption of the way to break the stack memory. Programmer can use to stop in the system state, out of the stack and interrupt stack block, according to the instructions of their reasons for failure to identify the host. Programmable Logic Controller in the repair of this is the most common way to effectively and rapidly.
Interface signal examination: through the use of programmable logic controller to check machine tool control system interface signals and the correct manual and interface signals relative ratio, also found the corresponding point of failure.
Diagnosis of spare parts to replace Law: Most modern CNC system is modular design, divided according to different functions in different modules, with modern technology, the development of the integrated circuit the increasing scale of technology is also more complex, according to conventional methods, it is difficult to fault location to put a very small region, and when the system failure, in order to reduce downtime, we can according to the function module and fault phenomena, the initial judge the possible fault module, with the diagnosis of spare parts to replace it, so can quickly determine the The module has a fault. In the absence of diagnosed cases of spare parts can be used at the scene the same or compatible replacement module inspection, repair of the modern CNC, an increasing number of cases using this method of diagnosis, and then use the spare parts to replace damaged module, allowing the system to normal. The greatest extent possible to reduce downtime, use this method when they are in operation attention must be carried out in the blackout state, but also double-check the PCB version, model, a variety of markers, cross-access it the same as for the machine tool-related data and potentiometer position record should be prepared, should be well marked suture removal.
Use of system self-diagnostic function to determine: a modern CNC system in particular, are full-function NC has a strong ability to self-diagnosis, when the monitoring system through the implementation of the various parts of the job and promptly determine the failure, give the police information, and make corresponding action to avoid the accident. But sometimes when the hardware failure, will not be able to report to the police, and some numerical control system through the LED flashes different frequency or different combinations to make the corresponding instructions, these instructions can be used to help us accurately diagnose faults template. SINUMERIK 8 system such as MS100 CPU board in accordance with the four lights and operation panel FAULT bright lights out combinations can determine fault location.
The above diagnostic methods, in practical applications there is no strict time limits, may be able to use a method of troubleshooting may also require a number of ways at the same time. Its effect depends primarily on the principle of the system and structure of the depth of understanding and grasp, as well as the number of repair experience.
3.2 NC System Fault Analysis
Numerical control system in accordance with the composition, working principle and characteristics, combined with our experience in the repair will be a common phenomenon of fault location and fault analysis are as follows.
(1) This is the position loop control instructions issued by NC system, and position detection system compared to the value of the feedback to further complete the mission control of a key aspect. It has a very high frequency of job and peripherals connected, so prone to failure.
Common fault has: ① digital control loop warning: may be open loop measurements; measurement system damage, internal damage-bit ECU. ② instructions on the hair do not exercise, may be drifting too high, positive feedback, digital control unit breakdown; measurement component damage. ③ measurement component failure, the general performance without feedback value; machine can not return to reference point; high-speed pulse generator when the leak likely cause alarm or read the first grating are dirty; grating broken.
(2) Servo Drive System Servo drive system and power grid, and other associated mechanical systems, but also in the work has been in frequent start-up and running, so this is also part of larger failures.
Its main fault has: ① system damage. General because of the network voltage fluctuations or voltage shocks. Power quality in most areas of China's poor, will bring voltage transfinite machine, especially the moment overrun, such as non-specific voltage monitor, it will be difficult to detect, in the search when the cause of the malfunction, it is necessary to take note, there are Some reasons are because of special damage. Such as a factory in northern China because of lightning in the plant substation and caused many Power Units tools servo system damage. ② no control instructions, the electrical high-speed operation. This failure is due to the speed loop or open-loop positive feedback. Such as a factory in the northeast, the introduction of the Federal Republic of Germany Wotan rotor milling companies in debugging, the machine tool X-axis in the absence of instructions, the high-speed operation, by the analysis that we think are caused by positive feedback. Since the system zero drift, in the case of positive feedback, it will enable the rapid accumulation of motors at a high speed operation, and we check the line after the tag by completely correct, Machine Tool Plant technicians mistake then consider impossible in the full analysis and testing we will Reverse feedback line, the results of machine operating normally. Machine Tool Plant and technical personnel have to admit mistakes in the work of the German side. There is one example, we have a factory in Tianjin, training lectures should be the attitude of the management requirements of their Units from one plant into the plant have not been able to work properly after the repair of precision grinding machines for its failure are: 1 start motor on the machine running, but also a growing the sooner, until the maximum speed. Consider our analysis because of the speed loop are open, the system can not suppress drift caused. The reason is that after inspection line speed feedback received to the online result. ③ processing surface fail, go-for-axis circular interpolation to convex when Units, or electric low-speed crawling, or vibration, such failure is usually because of improper adjust servo system, the system does not gain the same axis or in connection with motor caused by inappropriate matching, the solution is optimized adjustment. ④ blown insurance, or motor overheated and burned, such failures are usually mechanical load is too large or the card die.
(3) part of the power supply system is to maintain a normal job to support the energy part of the failure or failures are caused by direct result of system downtime or damage to the entire system. General in Europe and the United States, relatively few of these questions, in the design considerations in this area much, but in China, because of volatile power supply, poor quality, but also to hide like a high-frequency pulse of this type of interference, plus man-made factors (such as sudden power outages, etc.). These reasons can cause power failure to monitor or damaged. In addition, the numerical control system to run some data, settings data and processing procedures stored in RAM memory in general, the system after power failure, battery backup power supply on or lithium batteries to maintain. Thus, a longer period of downtime, plug the power or memory can cause data loss, the system should not run.
(4) programmable logic controller interface numerical control system logic control,database management, hydraulic start and so on, mainly by the PLC to achieve, it is necessary to the completion of these controls must be collected on the status of the control point information, such as broken electrical , servo valves, lights and so on. Thus it with the outside world a wide range of variety of signal sources and the implementation of components linked to frequent changes, so the possibility of the failure of many more, but also the ever-changing fault type.
(5) other because of environmental conditions, such as interference, temperature, humidity exceed the scope of permit, improper operation, improper parameter settings, but also may result in downtime or failure. One factory has CNC equipment, the boot soon after the loss of NC ready signal, the system can not work, the examination revealed a very high body temperature because the ventilation filters have been blocked, causing the temperature sensor movements, replacement of filters, the system normal job. Not according to rules-swappable circuit boards, with or without protective measures, such as static electricity may cause malfunction or even destruction of system downtime.
General in the numerical control system design, use and repair, we must consider are frequently out of position to give alarm, alarm circuit after the job, on the one hand on the screen or operating panel give the police information, on the other hand the issue of interruption of the protective directive, allowing the system to stop working to identify and repair faults.
3.3 Troubleshooting Method
(1) initialization reset method under normal circumstances, because of the instantaneous system failure alarm, the available hardware reset or switch the system power in order to remove the fault, if the system is down because of storage areas, pluggable circuit board or battery voltage cause confusion, it must be cleared to initialize the system, removing the former should pay attention to make copies of data records, if initialization can not be ruled out after the fault is still, were carried out in hardware diagnosis.
(2) the parameters change, the program is more actual system parameters are determined based on system functions, parameter settings may cause errors on the system failure or a functional null and void. For example, a factory in Harbin rotor milling machine using a measurement of the circulatory system, the functional requirements have a background memory, debugging and found this feature can not be achieved. Examination revealed the background to determine the existence of memory data bit is not set, after setting the normal function. Sometimes, because of procedural errors can be caused by user downtime, which can be used search function block system to inspect and correct all errors, in order to ensure its normal operation.
(3) regulation, adjust the best method of regulation is one of the most simple solution. Potentiometer through regulation, to amend system failures. Such as a factory repair, the system displays the screen of their confusion, as adjusted to normal. A factory in Shandong, the spindle in the start-up and braking skid occurs when a belt because of its large spindle load torque, and drives the ramp-up time setting is too small, the adjusted normal.
Optimization are systematically adjust servo drive system and mechanical system was dragging achieve the best match of the integrated regulation of methods, their approach is very simple, with a multi-line recorder or dual trace storage oscilloscope, respectively, observation of instruction and speed feedback or current feedback response relationship. By regulating the speed regulator proportional coefficient and integral time, to make servo systems that have a higher dynamic response without oscillation of the best working condition. At the scene no oscilloscope or recorder of circumstances, based on experience, that is, adjust so that the electrical start-up, and then slowly adjust to the reverse, until you can eliminate the shock.
(4) replacement spare parts spare parts for the replacement of law with well diagnosed a bad circuit board, and make the corresponding initialization start, so that the normal operation of machine tools quickly, and then repair or rework bad board, which is currently ranked the most commonly used because approach.
(5) to improve the power quality of law is generally regulated power supply used to improve power supply fluctuations. For high-frequency interference filtering capacitor can be used by these preventive measures to reduce the power supply board failure.
(6) maintenance of information-tracking some of the large manufacturing company based on actual work because of design defects caused by accidental failure, have been revising and perfecting the system software or hardware. These changes to the form of constant repair information available to maintenance personnel. Used as the basis for troubleshooting can be completely correct troubleshooting.
3.4 repair should pay attention to matters
(1) removed from the machine on a piece of circuit board, the Record should be noted that their relative position should be to connect its cable for fixed installation of the circuit board, it should be removed before and after the press-fit parts and screws for record purpose. Demolition under the pressure parts and screws should be placed on a dedicated box, so as to avoid loss, the assembly, the box should be all things to use, otherwise the assembly is incomplete.
(2) electric soldering iron should be placed on the front easily, stay away from the circuit board repair. Jerdonii Dressing should be appropriate to meet the integrated circuit welding, and to avoid bumps when welding other components.
(3) measuring the resistance between lines should be broken power supply, measured resistance should be red and black table pen exchange measurements twice a year to a large value for the reference value.
(4) circuit board solder films have mostly brush, so measurements should be to find the corresponding point as the test spot, do not eradicate the solder film, and some board all the brush has the insulating layer, only in the solder joint Department with a blade and scratch - insulating layer.
(5) should not be arbitrarily cut off the printed circuit. Some maintenance personnel have some experience in home appliance repair, custom line check, but the numerical control devices are double-sided circuit board or metal plate of multi-hole plate, printing fine lines and dense, once cut off the hard welding, and easy to cut off tangent when the adjacent line, again some point, a cut off of a line, and should not make it and line out, required a few lines got cut off simultaneously.
(6) should not be components. Some maintenance personnel identifying fault components in the absence of circumstances that only the seat of your pants a component breaks down,immediately, so that a higher rate of miscarriage of justice, of the components removed artificially higher failure rate.
(7) should be used to demolish component suction device and suction tin tin rope, should not have the hardware check. The same heating pad should not be a long time and repeat the demolition to avoid damage to pad.
(8) replacement of the device, the pin should be an appropriate treatment, welding welding should not be used in acidic oil.
(9) Record lines switch, jumper position, it should not be changed. For more than polarization control inspection, or swap components on-board when the attention of all components tag in order to avoid disorder, with the result that a good board should not work also.
(10) investigated the power circuit board configurations and types, according to the required inspection can be powered separately or all of power. Should pay attention to high-pressure, and some direct access to high-voltage circuit board, or board has high-voltage generator, in need of appropriate insulation, should pay special attention to the operation.
4 CNC machine tools boot debugging
CNC machine tools is a high technology machinery and instruments of integration tools, the user to buy a CNC machine tool whether the correct safety boot, debugging is a crucial move. This step is the correct decision in large CNC machine tools that can exert Units normal economic efficiency and service life of its own, which is CNC machine tool manufacturers and users of the factory are very important issues. CNC machine tools boot, debugging the following steps should be carried out.
4.1 prior to the appearance of electricity inspection
(1) Open the machine tool inspection machine appliances electric control box, check the relays, contactors, fuses, servo motor speed control unit socket, the spindle motor speed control unit such as the availability of loose sockets, if loosening should be back to normal state, has locking institutions must be locking connector, adapter box has a machine must check the box on the socket adapter, the availability of loose wiring, has locking bodies must be locked.
(2) CNC electric box to check door open CNC electric box to check all types of socket interface, servo motor feedback line socket, the spindle pulse generator socket, hand pulse generator socket, CRT sockets, etc., if loose to re-plugged, Has locking bodies must be locked. Printed circuit board in accordance with the instructions to check all the settings for the situation of short-circuit terminals must be in line with the machine tool manufacturing plant set up a state, there are incorrect should be re-instated, under normal circumstances do not re-instated, but users must be on the short-circuit terminal settings do a good job in the state of original records.
(3) Quality Inspection inspect all wiring the terminal block. Including the strength of electric machine assembly plant on its own terminal and the electrical wiring of the power cord terminals, each terminal must be used with fastening rotating once, until the use of a rotary screw fixed date, all the electrical sockets must be tightened.
(4) solenoid valve solenoid valve check all hands must be promoted several times in order to prevent a long time is not caused by electricity adverse action, such as abnormal, should be prepared records, to prepare for power after the confirmation be repaired or replaced.
(5) check the check all limit switch limit switch moves the flexible and fixed it firmly and found that the adverse action is not solid or fixed should be addressed immediately.
(6) Operation panel buttons and switches for inspections of the operation panel buttons, switches, wiring lights and found that an error should be dealt with immediately, inspection unit on CRT socket and wiring.
(7) Ground inspection requirements have a good ground wire, ground wire measuring machine, grounding resistance should not greater than 1Ω.
(8) power supply phase sequence check sequence table used to check phase sequence of input power, input power to confirm the phase sequence and machine tool calibration throughout the power phase sequence should be absolutely consistent. Secondary Wiring has the equipment, such as power transformers, the secondary wiring must confirm the consistency of the phase sequence. To ensure that throughout the phase sequence is absolutely correct. Supply voltage to be measured at this time, do a good job records.
4.2 machine connected to the total voltage
(1) the total power supply connected to machine tools, inspection CNC electric box, spindle motor cooling fans, machine tool cooling fan electrical box steering is correct, lubrication, hydraulic oil, etc., as well as signs in the machine tool lighting and whether it is normal, the fuse has no damage, if any abnormal power failure should immediately overhaul, no abnormality can continue.
(2) measurement of the various parts of strong electric voltage, especially for the CNC and servo power unit used in the initial-level voltage transformer and to prepare themselves Record.
(3) to observe whether or not oil spills, especially for the turret to place cards tight, and the shift spindle chuck tight cards, etc. of the hydraulic cylinder and solenoid valve. If oil spills should be immediately repaired or replaced blackout.
Box 4.3 CNC electric power
(1) CNC electricity power button, power supply connected to CNC to observe the CRT display, until the normal screen. If the ALARM display, it should be looking for fault and ruled out at this time should be re-sent to check the electricity.
(2) Open CNC power, in accordance with the relevant information on the test terminal give the location of measurement at all levels of voltage, bias has to be adjusted to a given value, and to prepare themselves Record.
(3) the state of switches placed in appropriate locations, such as Japan FANUC system should be placed in MDI, and choose to go to the page parameter. Bit-by-one by one to check the parameters, these parameters should be consistent with random brought in line with the parameter table. Such as are found inconsistent parameters, should understand the significance of various parameters and then decide whether or not to modify, such as backlash compensation value may be inconsistent with the parameter table, which in the actual processing can be modified at any time.
(4) the state of selector switch placed in the JOG position, will move the speed on the most low-grade, respectively positive and negative direction of the coordinates to move the operation, and simultaneously to move the hand according to the direction of the corresponding super-way protection switch, verify the reliability of its protective role, and then carry out the super-slow-way test, to verify the installation of ultra-way collision block is correct.
(5) will be placed in a state of switch back to zero position, the completion of the operation back to zero, the reference point return movements are not completed will not be able to carry out other operations. In such cases therefore should first carry out this operation, then we will proceed to item (4) operation.
(6) will be placed in a state of switch JOG position or MDI position, manually change file test will verify the minimum spindle speed control switch on the location of the file to the main axis of positive tests, observation of the spindle and the speed of operation show the correctness, and then gradually speed up to the highest speed, to observe the functioning of the stability of the spindle.
(7) manual rail lubrication test, so have a good rail lubrication.
(8) changes gradually shift ultra-fast transfer switch and the feed rate switch, to move the tool carrier at random to observe the correctness of the speed of change.
4.4 MDI test
(1) measuring the actual speed of the spindle lock switch on the machine connected to the location, using manual data entry instructions, carry out arbitrary variable spindle files, variable-speed test, measuring the actual spindle speed, spindle speed and observe the displayed value, adjust its error should be limited to within 5%.
(2) conducted or knife Block turret election knife test its purpose is to examine the knife block, or are, inversion and the correctness of positioning accuracy.
(3) function tests in accordance with the order situation is different, different functions can be made under the specific circumstances of each functional test. To prevent accidents from happening, the best first test machine is locked, and then open up a pilot machine.
(4) EDIT function tests will be placed in a state of EDIT selector switch position, to produce one easy process, as much as possible, including various functions and auxiliary functions of command instructions, mobile dimension to the largest machine tool stroke is limited, the procedure at the same time increase delete and modify.
(5) the state of the tests will be automatically locked machine, with the preparation of operating procedures and air test, to verify the correctness of the procedure, and then open up machine tools, feed rate, respectively, switches, ultra-fast transfer switch, spindle speed overshoot many switch kinds of changes in machine tool switches in the above circumstances a variety of changes in full operation, after the overshoot at switch 100% office to enable the full operation of machine tools to observe the work of the whole are normal.
At this point, a numerical control machine tool to be finished debugging boot.
5 After the repair debug technology deal
At the scene after the repair, maintenance records should be carefully filled out a list of essential spare parts list, set up user profiles for the failure time, the phenomenon of diagnostic methods, the use of scheduling methods so that if there should be a detailed record of the remaining issues, such not only for each fault are well documented, but also the accumulation of repair experience.
Above repair techniques for numerical control system as described in nearly a hundred years we are the number of control system debugging and maintenance experience. Although a wide range of numerical control system, fault is ever changing methods of repair are not the same, it is difficult to make a short reference, but we still wish to put some of the basic methods and ideas to write out, and everyone can communicate with a view to raise awareness of CNC system emphasis on repair techniques, repair techniques and results of the direct purpose is to enable the numerical control system to resume normal operation, thus ensuring the smooth progress of production. At present, numerical control technology in our country is rapidly infiltrate to the industrial sector, with the development of electronic technology, numerical control technology in the national economy also increases, then for an important component of the CNC Technology - CNC System repair techniques should also adapt quickly to the rapid development of numerical control technology requirements, as a numerical control system maintenance and technical personnel, they should be constantly learning and mastering new knowledge and technology, looking for a new diagnosis of repair methods and means to promote a few control system repair technology development and make due contributions. Readmore »»