CNC maintenance technology is not only a prerequisite for ensuring normal operation, but also plays a huge role in promoting the development and improvement of numerical control technology. Therefore, it has become a specialized discipline.
In addition, any CNC device is a process control device, which requires it to work flawlessly at every moment of real-time control. Any part of the fault and failure will cause the machine to stop, causing production to stop. Therefore, it is very necessary to repair the CNC system with such a complicated and precise structure. Especially for the introduction of CNC machine tools, most of them cost hundreds of thousands to tens of millions of dollars. In many industries, these devices are in critical positions, and if they fail to repair and troubleshoot in the event of a failure, they will cause significant economic losses.
There is still a big gap between our existing maintenance status and level and the level of design and manufacturing technology of imported equipment. The reasons for the gap are: poor quality of personnel, lack of digital testing and analysis methods, test analysis techniques for digital domain and digital domain and frequency domain synthesis, etc.
Below we start with the basic composition of modern CNC system, and explore the diagnosis and maintenance of CNC system.
The composition and characteristics of the numerical control system <br> At present, there are many kinds of numerical control systems in the world, each with different forms, and their respective structures have their own characteristics. These structural features are derived from the basic requirements of the initial design of the system and the ideas of engineering design. For example, there are very different requirements for point control systems and continuous trajectory control systems. For the T system and the M system, there is also a big difference. The former is suitable for the processing of parts of the rotary body, and the latter is suitable for the machining of parts of the irregular non-rotating body. For different manufacturers, based on historical development factors and the influence of different factors that vary from place to place, the design ideas may also have their own advantages. For example, the Dynapath system in the United States uses a small plate structure to facilitate board replacement and flexible integration, while the Japanese FANUC system tends to a large plate structure, which is beneficial to the reliability of the system work, and the average failure-free rate of the system is continuously improved. However, no matter which system, their basic principles and composition are very similar. Generally, the entire CNC system consists of three major components, namely the control system, the servo system and the position measurement system. The control system performs interpolation calculation according to the machining part program, and sends a control command to the servo drive system; the servo drive system amplifies the control command, and the servo motor drives the machine to move as required; the measurement system detects the movement position or speed of the machine, and feeds back to the control System to correct control commands. These three parts are organically combined to form a complete closed-loop controlled CNC system.
The control system mainly consists of bus, CPU, power supply, memory, operation panel and display screen, position control unit, programmable controller logic control unit and data input/output interface. The latest generation of CNC systems also includes a communication unit that completes internal data communication between the CNC and PLC and external high-level network connections. The servo drive system mainly includes a servo drive and a motor. The position measuring system is mainly an incremental displacement encoder using a long grating or a circular grating.
The main features of the CNC system are: high reliability requirements: because once the CNC system fails, it will cause huge economic losses; it has a high environmental adaptability, because the CNC system is generally an industrial control machine, and its working environment is the workshop environment. It has the ability to work under the environmental conditions of vibration, high temperature, humidity and various industrial interference sources; the interface circuit is complex, the numerical control system must be matched with various numerical control equipment and external equipment, and it is necessary to deal with various situations in the production process at any time. It adapts to various process requirements of the equipment, and thus the interface circuit is complicated and frequently works.
Basic conditions for maintenance of modern CNC systems
2.1 Basic conditions of the maintenance staff The maintenance work is carried out in good or bad depending on the personnel conditions. The maintenance staff must have the following requirements:
High sense of responsibility and good professional ethics;
Extensive knowledge, master the basic knowledge of computer technology, analog and digital circuit foundation, automatic control and motor drag, detection technology and machining technology and a certain level of foreign language;
After good technical training, master the working principle of CNC, drive and PLC, and understand the CNC programming and programming language;
Familiar with structure, with experimental skills and strong hands-on ability;
Master all kinds of commonly used (especially on-site) test instruments, instruments and tools.
2.2 Conditions for maintenance should be prepared with common spare parts and accessories; actual support or supply of microelectronic components can be obtained at any time; necessary maintenance tools, instruments, meters, wiring, and microcomputers. It is best to have a small programming system or programmer to support equipment debugging; complete documentation, manuals, wiring diagrams, maintenance instructions (including CNC operating instructions) and interfaces, adjustments and diagnostics, drive manuals, PLC manuals (including PLC user program lists) ), component tables, etc.
2.3 Preparation before maintenance After receiving the direct request from the user, you should contact the user as directly as possible to obtain on-site information, site conditions and fault information as soon as possible. Such as CNC machine feed and spindle drive models, alarm indications or fault phenomena, and whether there are spare parts at the user site. Based on this, analyze the possible causes and locations of the faults, and then prepare the relevant technical materials, maintenance service tools, and equipment spare parts before starting to the site.
On-site repair
On-site maintenance is to diagnose the faults (mainly the CNC part) of the CNC machine tool, find out the fault location, replace the corresponding normal spare parts, and return the machine to normal operation. The key to this process is diagnostics, which is to detect the system or peripheral lines, determine if there is a fault, and indicate the exact location of the fault. From the positioning of the whole machine to the patch panel, in some cases even the components are located. This is the main part of the entire repair work.
3.1 The preliminary judgment of the fault diagnosis of the numerical control system is usually carried out when the data is full, the fault can be judged by data analysis, or the interface signal method can be used to identify the faulty part according to the fault phenomenon, and then according to the fault and the specific characteristics of this part, Check one by one, preliminary judgment. In practical applications, it is possible to find faults and eliminate them in one way, sometimes using multiple methods. The degree of mastery of the various methods for determining the fault point depends mainly on the depth of mastery of the principle and structure of the faulty device.
Alarm processing 1 System alarm processing: When the CNC system fails, the fault signal and corresponding information are generally given on the display or operation panel. Generally, the system's operation manual or adjustment manual has detailed alarm numbers, alarm contents and processing methods. Because the system's alarm settings are single, complete, rigorous, and clear, maintenance personnel can handle the information according to the information and processing methods given after each alarm. 2 Machine tool alarm and operation information processing: According to the electrical characteristics of the machine tool, the machine tool manufacturer applies PLC program, and some fault or operation information that can reflect the electrical control of the machine interface is given by the display with specific signs, and can be specified by Key, see a more detailed description of the alarm. This kind of alarm can be processed according to the troubleshooting manual provided by the machine tool manufacturer. It can also use the operation panel or programmer to find the corresponding signal status according to the circuit diagram and PLC program, and find the fault point according to the logic relationship for processing.
Fault handling without alarm or alarm When the PLC of the system cannot run, the system has stopped or the system has no alarm but the work is not normal, it is necessary to use the theoretical basis that has been mastered before the fault occurs, and analyze it. The correct judgment. This troubleshooting is explained below.
Fault diagnosis method The routine inspection method visually inspects the fault board, and carefully checks whether the fuse is blown, the components are burnt, smoked, cracked, and there is no foreign matter breaking. In this way, it can be judged whether there is any problem such as overcurrent, overvoltage, and short circuit in the panel.
Hand touch and gently shake the components, especially the resistance, the semiconductor device has a sense of looseness, so as to check some broken feet, solder joints and other issues.
Power on first use a multimeter to check whether there is any disconnection between the various power sources, if not, you can access the corresponding power supply, visually detect whether there is smoke, fire, etc., whether the hand touches the component with abnormal heat, so you can find some Significant failures, and narrowing the scope of inspection.
For example, when a fault is detected in a factory in Harbin, the CNC system and PLC of the machine tool are running normally, but the hydraulic system of the machine tool cannot be started. The programmer is checked to run normally with the programmer, and the required signal states are all met. Further inspection revealed that the PLC signal status was inconsistent with the markings on the drawings and equipment. The board was unloaded and checked. It was found that the two output boards of the PLC were incorrectly addressed, and the other two positions were misplaced. After the exchange, the machine tool was running normally. For the SIMATIC S5?150K programmable controller used in the machine where this fault occurs, the system can operate normally regardless of the position of the board, as long as the addressing is correct, but the actuator and signal source must correspond correctly. Once the corresponding error occurs, it will malfunction and even destroy the machine. In addition, according to the fault phenomenon provided by the user, combined with its own on-site observation, the system working principle can also be used to quickly make a correct judgment.
Instrument measurement method When the system fails, the conventional electrician detection instrument and tools are used to measure the voltage, power supply and pulse signal of the fault part according to the system circuit diagram and the machine circuit diagram to determine the fault. If the input voltage of the power supply exceeds the limit, the power supply monitor can use the voltage meter to measure the network voltage, or use the voltage tester to monitor in real time to eliminate other causes. If a position control loop fault occurs, the oscilloscope can be used to check the signal state of the measurement loop, or use an oscilloscope to observe whether the signal output is out of phase or not. For example, in a factory in Shanghai, the system alarmed, the position loop hardware failed, and the oscilloscope found that there was an interference signal. We filtered it in the circuit to make the system work normally. If there is a situation where the system cannot return to the reference point, the oscilloscope can be used to check if there is a zero mark pulse. If it is not considered, the measurement system is damaged.
PLC interrupt status analysis with programmable controller: When the programmable controller fails, the cause of the interrupt is memorized by interrupting the stack. Use the programmer to call up the interrupt stack and block stack when the system is stopped, and find out the fault for the reason indicated. This is the most commonly used and efficient method in the maintenance of programmable controllers.
Interface signal check: By checking the interface signal of the machine control system with the programmable controller and comparing it with the correct signal of the interface manual, the corresponding fault point can also be found.
Diagnostic spare parts replacement method: Most modern CNC systems adopt modular design, and different modules are divided according to functions. With the development of modern technology, the scale of circuit integration is getting bigger and bigger, and the technology is more and more complicated. According to conventional methods, it is difficult to The fault is located in a small area, and in the event of a system failure, in order to reduce the downtime, we can initially determine the possible fault module according to the function and fault phenomenon of the module, and replace it with the diagnostic spare part, so that it can be quickly judged. Faulty module. In the absence of diagnostic spare parts, the same or compatible modules in the field can be used for replacement inspection. For the maintenance of modern CNC, more and more cases use this method for diagnosis, and then replace the damaged module with spare parts to make the system work normally. . Try to shorten the downtime as much as possible. When using this method, be sure to perform the power outage during operation. Also check the version, model, various markings, and the jumper of the board. For the relevant machine data and The position of the potentiometer should be recorded, and the mark should be made when the line is removed.
It is judged by the self-diagnosis function of the system: the modern numerical control system, especially the full-function numerical control, has a strong self-diagnosis ability. By implementing the work of various parts of the system during the implementation, the fault is judged in time, the alarm information is given, and corresponding actions are performed. Avoid accidents. However, sometimes when the hardware fails, it can't alarm. Some CNC systems can make corresponding indications through the different flashing frequencies or different combinations of the LEDs. These instructions can help us accurately diagnose the location of the fault template. . For example, the SINUMERIK 8 system can determine the fault location based on the combination of the four indicators on the MS100 CPU board and the FAULT light on the operator panel.
The above diagnostic methods have no strict limits in practical application, and may be eliminated by one method, and may also require multiple methods to be performed simultaneously. The effect depends mainly on the understanding and mastery of the system principle and structure, as well as the maintenance experience.
3.2 Common Fault Analysis of CNC System According to the composition, working principle and characteristics of the CNC system, combined with our experience in maintenance, the common fault locations and fault phenomena are analyzed as follows.
Position loop This is the key link for the CNC system to issue control commands and compare it with the feedback value of the position detection system to further complete the control task. It has a high frequency of operation and is connected to peripherals, so it is prone to failure.
Common faults are: 1-position control loop alarm: It may be that the measurement loop is open; the measurement system is damaged, and the position control unit is damaged internally. 2 Movement without command, may be excessive drift, positive feedback, position control unit failure; measurement component damage. 3 measurement component failure, generally showed no feedback value; the machine tool can not return to the reference point; the high-speed leakage pulse can cause the alarm may be caused by the grating or the read head is dirty; the grating is broken.
The servo drive system servo drive system is associated with the power grid, mechanical system, etc., and it is always in a state of frequent start and run during operation, so this is also a part with more faults.
The main faults are: 1 system damage. Generally due to network voltage fluctuations, or voltage shocks. In most parts of China, the quality of the power grid is not good, which will bring voltage overrun to the machine tool, especially the instantaneous overrun. If there is no special voltage monitor, it is difficult to measure. When looking for the cause of the fault, pay attention to it. Some are damage caused by special reasons. For example, a machine in North China caused damage to multiple machine tool servo systems due to lightning strikes at the plant substation and into the power grid. 2 There is no control command, and the motor runs at high speed. The cause of this failure is the speed loop open loop or positive feedback. For example, in a factory in Northeast China, the introduction of the West Germany WOTAN rotor milling machine in the commissioning, the machine X-axis in the absence of instructions, high-speed operation, after analysis we believe that is caused by positive feedback. Because the system zero drift, in the case of positive feedback, it will quickly accumulate the motor to run at high speed, and we check the line after the label is completely correct, the machine tool factory technicians think that it is impossible to connect wrongly, after full analysis and testing, we will The feedback line is reversed and the machine is operating normally. The technicians of the machine tool factory had to admit that the German side had made a mistake. There is another example. When we were training in a factory in Tianjin, we asked the factory to repair a precision grinding machine that had not been working properly after entering the factory. The fault was: the machine started to run when the motor started, and the more it came. The faster, up to the maximum speed. Our analysis believes that due to the speed loop open circuit, system drift cannot be suppressed. The reason for the inspection was that the speed feedback line was connected to the ground. 3 The surface of the workpiece does not meet the requirements during machining. When the circular interpolation axis is reversing, the boss appears, or the motor creeps or vibrates at a low speed. This type of fault is generally caused by improper adjustment of the servo system, and the gain systems of the axes are not equal or related to the motor. If the match is not appropriate, the solution is to optimize the adjustment. 4 The fuse is blown, or the motor is overheated and burnt. This type of fault is generally caused by excessive mechanical load or jam.
The power supply part of the power supply is the energy support part that maintains the normal operation of the system. The direct result of failure or failure is the system shutdown or the destruction of the entire system. Generally, in Europe and the United States, there are few such problems, and there are not many factors in design. However, in China, due to large fluctuations in power supply and poor quality, there are hidden interferences such as high-frequency pulses, plus artificial Factors (such as sudden pull-off, etc.). These causes can cause power failure monitoring or damage. In addition, part of the numerical control system operating data, setting data and processing programs are generally stored in the RAM memory, and after the system is powered off, it is maintained by a backup battery or a lithium battery of the power source. Therefore, the downtime is relatively long, and the power supply or the memory may be lost, and the system may not operate.
Programmable controller logic interface The logic control of the CNC system, such as tool magazine management, hydraulic start, etc., is mainly realized by PLC. To complete these controls, it is necessary to collect the status information of each control point, such as breaker, servo valve, indication. Lights, etc. Therefore, it is connected with various kinds of signal sources and actuators with a wide variety of externalities, and there are many changes, so there are many possibilities for failure, and the types of faults are ever-changing.
Others due to environmental conditions, such as interference, temperature, humidity exceeding the allowable range, improper operation, improper parameter settings, may also cause downtime or failure. There is a CNC equipment in the factory. After the startup, the CNC is ready to lose the signal. The system can't work. After checking, the temperature of the body is very high. The reason is that the ventilation filter has been blocked, causing the temperature sensor to operate. After the filter is replaced, the system works normally. . Failure to remove the circuit board according to the operating procedures, or non-static protection measures, may cause downtime or even damage the system.
Generally, in the design, use and maintenance of the numerical control system, it is necessary to give an alarm to the parts that often fail. After the alarm circuit works, on the one hand, the alarm information is given on the screen or the operation panel, and on the other hand, the protective interrupt instruction is issued. Stop the system to troubleshoot and repair.
3.3 Troubleshooting Method Initialization Reset Method Under normal circumstances, due to system alarm caused by transient fault, hardware reset or switch system power supply can be used to clear the fault in turn. If the system working storage area is powered off, plugging or unplugging the circuit board or battery undervoltage If it is confusing, the system must be initialized and cleared. Before cleaning, pay attention to making a copy of the data. If the fault cannot be eliminated after initialization, perform hardware diagnosis.
Parameter change, program correction method The system parameter is the basis for determining the system function. If the parameter setting is wrong, the system may be faulty or a function may be invalid. For example, a measuring cycle system was used on a rotor milling machine in a factory in Harbin. This function requires a background memory, which was found to be unworkable during commissioning. The check found that the data bit existing in the background memory was not set, and the function was normal after being set. Sometimes due to user program errors can also cause downtime, you can use the system's block search function to check and correct all errors to ensure their normal operation.
Adjustment, optimization adjustment adjustment is one of the easiest ways. Correct system failure by adjusting the potentiometer. For example, in the maintenance of a military factory, the display screen of the system is chaotic and normal after adjustment. In a factory in Shandong, the main shaft has a belt slip during start-up and braking, because the main shaft load torque is large, and the ramp-up time of the drive unit is set too small, and it is normal after adjustment.
The optimization adjustment is a comprehensive adjustment method that systematically achieves the best match between the servo drive system and the driven mechanical system. The method is very simple, using a multi-line recorder or a dual-track oscilloscope with storage function, respectively Observe the response relationship between the command and speed feedback or current feedback. By adjusting the speed factor and integration time of the speed regulator, the servo system can reach the optimal working state with high dynamic response characteristics without oscillation. In the absence of an oscilloscope or recorder on site, according to experience, the adjustment causes the motor to start to oscillate, and then slowly adjusts in the reverse direction until the oscillation is eliminated.
The spare parts replacement method replaces the bad circuit board with a good spare part, and performs the corresponding initial startup, so that the machine tool can be put into normal operation quickly, and then the bad board is repaired or repaired. This is the most common troubleshooting method at present.
The improved power quality method currently generally uses a regulated power supply to improve power supply fluctuations. Capacitance filtering can be used for high frequency interference, and these preventive measures are taken to reduce the failure of the power board.
Maintenance Information Tracking Method Some large manufacturing companies continually modify and improve system software or hardware based on accidental failures due to design defects in actual work. These modifications are continuously provided to maintenance personnel in the form of maintenance information. As a basis for troubleshooting, this can be completely and completely eliminated.
3.4 Matters needing attention during maintenance When taking out a certain circuit board from the whole machine, pay attention to record its corresponding position, the cable number of the connection. For the fixed installation of the circuit board, the corresponding crimping parts should also be removed before and after. And screws for recording. The pressed parts and screws should be placed in a special box to avoid loss. After assembly, all the contents of the box should be used, otherwise the assembly is incomplete.
The soldering iron should be placed in front of the hand, away from the repair circuit board. The soldering iron tip should be properly trimmed to accommodate the soldering of the integrated circuit and to avoid damage to other components during soldering.
When measuring the resistance between the lines, the power should be cut off. When measuring the resistance value, the red and black test leads should be interchanged twice, and the large resistance value is used as the reference value.
Most of the circuit boards are covered with a solder mask. Therefore, the corresponding solder joints should be found as test points during the measurement. Do not remove the solder film. If some of the boards are covered with an insulating layer, the insulating layer can only be scraped off with a blade at the solder joint.
The printed circuit should not be cut off at will. Some maintenance personnel have certain experience in appliance repair and are used to check for disconnection. However, most of the circuit boards on CNC equipment are double-sided metal orifices or multi-layered orifices. The printed circuit is fine and dense. Once cut, it is difficult to weld and tangent. It is easy to cut off adjacent lines, and then there are points. When cutting a certain line, it cannot be separated from the line. It is necessary to cut off several lines at the same time.
Components should not be replaced at will. Some maintenance personnel, if they do not determine the faulty component, simply change the component and immediately replace it, so that the false positive rate is higher, and the component with high damage is also high.
Use the tin and the suction cord when removing the components. Do not take them hard. The same pad should not be heated and removed repeatedly for a long time to avoid damaging the pad.
Replace the new device, the pins should be properly treated, and the acid solder should not be used in the soldering.
Record the switch on the line, the position of the jumper, should not be changed at will. When performing comparison inspections of more than two poles, or when interchanging components, pay attention to marking the components on each board to avoid confusion, and the good board will not work.
Check the power supply configuration and type of the circuit board. According to the inspection requirements, you can supply power or all power separately. Attention should be paid to high voltage, some circuit boards are directly connected to high voltage, or there is a high voltage generator in the board, which needs proper insulation, and special attention should be paid during operation.
CNC machine tool start-up <br> CNC machine tool is a high-tech electromechanical instrument integrated machine tool. After users buy a CNC machine tool, whether it is properly and safely turned on, debugging is a crucial step. The correctness of this step determines whether the CNC machine can play its normal economic efficiency and its own service life in a large program. This is a major issue for the production plants and user factories of CNC machine tools. When the CNC machine is turned on, the commissioning should be carried out according to the following steps.
4.1 Appearance inspection before power-on Machine tool electrical inspection Open the machine electrical control box, check the relay, contactor, fuse, servo motor speed, control unit socket, spindle motor speed control unit socket, etc., if there is loose, should return to normal state The connector with the locking mechanism must be locked. The machine with the adapter box must check the socket on the adapter box, the wiring is loose, and the locking mechanism must be locked.
CNC electric box check to open the CNC electric box door, check all kinds of interface sockets, servo motor feedback line socket, spindle pulse generator socket, manual pulse generator socket, CRT socket, etc. If you have loose, you need to re-plug it, there is locking The organization must be locked. Check the setting of the short-circuit terminal on each printed circuit board according to the instruction manual, and it must conform to the state set by the machine tool manufacturer. If it is wrong, it should be reset. Under normal circumstances, it is not necessary to reset it, but the user must set the short-circuit terminal. The status is the original record.
Wiring quality check Check all wiring terminals. Including the terminals of the strong and weak parts of the machine tool factory at the time of assembly and the terminals of the power lines of each motor, each terminal must be tightened once with a screwdriver until it is screwed with the screwdriver, each motor socket must be Tighten.
Solenoid valve check all solenoid valves must be pushed by hand several times to prevent malfunction caused by non-energization for a long time. If abnormality is found, make a record to confirm repair or replacement after power-on.
The limit switch checks and checks whether the flexibility and fixing of the limited position switch are firm. If it is found that the operation is poor or the fixing is not strong, it should be dealt with immediately.
Buttons and switches Check the buttons and switches on the operation panel, check all the buttons, switches, and indicators on the operation panel. If any errors are found, they should be processed immediately. Check the sockets and wiring on the CRT unit.
The ground wire inspection requires a good ground wire. The grounding resistance of the machine tool should not be greater than 1 Ω.
Power phase sequence check Use the phase sequence table to check the phase sequence of the input power supply. Verify that the phase sequence of the input power supply is absolutely consistent with the phase sequence of the power supply calibrated everywhere on the machine.
Equipment with secondary wiring, such as power transformers, must confirm the consistency of the phase sequence of the secondary wiring. Make sure that the phase sequence is absolutely correct. At this point, the power supply voltage should be measured and recorded.
4.2 Turn on the total voltage of the machine tool, check the total power supply of the machine, check the CNC electric box, the cooling motor of the spindle motor, the steering of the cooling fan of the machine tool box is correct, the oil mark indication of lubrication, hydraulics, etc. and the machine light are normal, Whether the fuse is damaged or not, if there is any abnormality, it should be immediately shut down for maintenance, and no abnormality can be continued.
Measure the voltage of each part of the high voltage, especially the primary and secondary voltages of the power transformer for the CNC and servo unit, and make a record.
Observe the oil leakage, especially the hydraulic cylinder and solenoid valve for the turret indexing, clamping, spindle shifting and chuck clamping. If there is any oil leakage, it should be repaired or replaced immediately.
4.3 Power on the CNC box Press the power button of the CNC power supply to turn on the CNC power supply and observe the CRT display until the normal screen appears. If the ALARM display appears, you should look for the fault and eliminate it. In this case, you should re-send the power check.
Turn on the CNC power supply and measure the voltage of each level according to the position of the test terminal given in the relevant data. The deviation should be adjusted to the given value and recorded.
Put the status switch in the appropriate position, such as the Japanese FANUC system should be placed in the MDI state, select the parameter page. The parameters are checked one by one, and these parameters should be consistent with the random parameter list. If there are inconsistent parameters, the meaning of each parameter should be clarified before deciding whether to modify it. For example, the value of backlash compensation may be inconsistent with the parameter table, which can be modified at any time after actual processing.
Place the state selection switch at the JOG position, place the jog speed at the lowest position, perform the jog operation in the forward and reverse directions of each coordinate, and simultaneously press the overtravel protection switch corresponding to the jog direction to verify its protection. The reliability is then followed by a slow overtravel test to verify the correctness of the overtravel block installation.
Put the status switch to the zero return position, complete the zero return operation, and the other operations cannot be performed if the action returned by the reference point is not completed. Therefore, in this case, you should perform this operation first, and then proceed to the fourth operation.
Put the status switch in the JOG position or MDI position, perform the manual shift test. After the verification, set the spindle speed switch to the lowest position, and perform the spindle forward and reverse test of each gear to observe the spindle running condition and the correctness of the speed display. Then gradually increase the speed to the maximum speed and observe the stability of the spindle operation.
Perform manual rail lubrication test to make the guide rails well lubricated.
Gradually change the rapid shift overshoot switch and the feedrate override switch, and jog the tool holder at random to observe the correctness of the speed change.
4.4 MDI test to measure the actual spindle speed The machine lock switch is placed in the ON position, use the manual data input command to perform any spindle shift, variable speed test, measure the actual spindle speed, and observe the spindle speed display value, adjust the error should be limited Within 5%.
The purpose of the knife selection test of the turret or the holder is to check the correctness of the holder or the positive, reverse and positioning accuracy.
The function test is different depending on the order of the order, and the function can be tested according to the specific situation. In order to prevent accidents, it is best to lock the machine for testing before releasing the machine for testing.
EDIT function test puts the state selection switch in the EDIT position, and compiles a simple program by itself, including as many function commands and auxiliary function commands as possible. The moving size is limited to the maximum stroke of the machine, and the program is added, deleted and modified. .
The automatic state test locks the machine tool, performs the dry running test with the programmed program, verifies the correctness of the program, and then releases the machine tool to make various changes to the feedrate override switch, the quick overshoot switch, and the spindle speed overshoot switch. The machine tool is fully operated under various changes of the above switches, and then the overshoot switches are placed at 100% to fully operate the machine tool and observe whether the working condition of the whole machine is normal.
At this point, a CNC machine tool is considered to be commissioned.
Technical treatment after repair and commissioning
After the on-site maintenance is completed, the maintenance records should be carefully filled out, the list of necessary spare parts should be listed, and the user files should be listed. For the fault time, phenomenon, analysis and diagnosis method, the troubleshooting method should be used. If there are any remaining problems, it should be recorded in detail. Not only makes each fault well documented, but it also accumulates maintenance experience.
The above explanation of the maintenance technology of the numerical control system is a summary of the experience of commissioning and maintenance of nearly one hundred control systems in our years. Although there are many kinds of numerical control systems, the faults are ever-changing, and the maintenance methods are not the same. A short article is difficult to describe, but we still hope to write some basic methods and ideas, and communicate with you in order to cause people to repair the CNC system. The emphasis and maintenance of the direct purpose and result of the maintenance technology is to restore the normal operation of the CNC system, thus ensuring smooth production. At present, in our country, numerical control technology is rapidly infiltrating into various industrial sectors. With the development of electronic technology, the position of numerical control technology in the national economy will also increase. Then, for the important components of numerical control technology, the maintenance technology of numerical control system should also be rapid. Adapting to the rapid development of CNC technology, as a CNC system maintenance technician, we should continuously learn and master new knowledge and technology, find new methods and means of maintenance diagnosis, and promote the development of CNC system maintenance technology. Deserved contribution.
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