Brand AVX TPSE226M035R0125 Low impedance tantalum capacitor AVX 22

Electronic scale crystal oscillator 3.2*2.5mm 3225 16M (16.000MHZ) 12PF 10PPM 20PPM 30PPM

SMD aluminum electrolytic capacitor

WIFI test head can be customized for other specifications

Single chip microcomputer STM32L151CCU6

In the process of fault detection, CNC machine tools should make full use of the self-diagnosis function of the CNC system to judge, and also use some common methods of fault checking.
1. Routine inspection method The routine inspection method mainly uses the human hand, eyes, ears, nose and other organs to observe various abnormal phenomena such as light, sound and taste when the fault occurs, and carefully observe every part of the system, following " The principle of “before and after the inside” is used to diagnose faults by means of looking, listening, sniffing, asking, and modulating. From the outside to the inside, the fault range can be reduced to a module or a printed circuit board. This requires maintenance personnel to have a wealth of practical experience, a multidisciplinary wide knowledge and comprehensive judgment. For example, CNC machine tools suddenly stop during machining. Open the CNC cabinet and check that the main circuit of the Y-axis motor is burnt out. After checking the components related to the Y-axis, it is found that the power line of the Y-axis motor has several wear points, which are placed on the bed and cause a short circuit. After the power line is replaced, the fault is eliminated and the machine tool returns to normal.
2. Self-diagnostic function method Although the modern numerical control system has not yet reached a high degree of intelligence, it has already possessed a strong self-diagnosis function. The hardware and software of the CNC system can be monitored at any time. Once an abnormality is found, an alarm message is displayed on the CRT or the LED is used to indicate the approximate cause of the fault. The self-diagnosis function can also display the status of the interface signal between the system and the host to determine whether the fault occurred in the mechanical part or the CNC system and indicate the approximate location of the fault. This method is the most effective method for current maintenance work.
3. Function program test method The so-called function program test method is to use the manual function or automatic programming method for the common functions and special functions of the numerical control system, such as linear positioning, circular interpolation, spiral cutting, fixed cycle, user macro program, etc. Into a functional program test program, sent to the CNC system, and then start the CNC system to run, in order to check the machine's performance and reliability of these functions, and then determine the possible cause of the failure. This method is difficult to determine whether it is a programming error or an operation error, or a cause of machine failure, is a good judgment for the inspection of the long-time idle CNC machine when the machine is turned on for the first time and the machine tool processing causes waste without alarm. method.
4. Spare Parts Replacement Method The spare part replacement method is a simple and easy method and one of the most commonly used methods for on-site judgment. The so-called spare parts replacement method is to analyze the fault cause, the maintenance personnel can replace the suspected part with the spare printed circuit board, template, integrated circuit chip or component, thereby narrowing the fault range to the printed circuit board or chip one. level. It is actually verifying the correctness of the analysis. However, before the replacement board is exchanged, the spare board should be carefully checked for integrity and the status of the spare board should be checked to be exactly the same as the original board. This includes the selection switch on the inspection board, the set position of the shorting bar, and the position of the potentiometer. When replacing the memory board of the CNC, it is often necessary to initialize the memory of the system (for example, the magnetic bubble memory used by the FANUC FS-6 system in Japan needs to perform this work), and reset various numerical control data, otherwise The system will still not work properly. Another example is to replace the memory board of FANUC's FS-7 system, and then re-enter the parameters and assign the memory area. Some CNC systems require some specific operations after replacing the motherboard. In short, it must be strictly in accordance with the requirements of the system operation and maintenance instructions.
Before deciding to replace a part, you should carefully check the relevant line and other related electrical equipment connected to it, and confirm that there is no fault before replacing the new one to prevent the external fault from causing damage to the replaced parts. Points to note when replacing spare parts are:
(1) Replacement of low-voltage electrical appliances should pay attention to voltage, current and other related technical parameters, and try to replace them with the same specifications.
(2) Replacement of electronic components, if they are not the same, the technical parameters should be similar, and the main parameters should better than the original replacement.
(3) Record the parts in disassembly, especially in places with a lot of wiring, to prevent human error caused by feedback errors.
(4) In the circuit with feedback link, pay attention to the polarity of the signal when replacing, to prevent other faults caused by feedback errors.
(5) When it is necessary to remove the same spare parts from other equipment, pay attention to the method, and do not damage the parts during disassembly. If you replace the board, check that the voltage used is normal before replacing the new board.
5. Transfer method The so-called transfer method is to exchange two printed circuit boards, templates, integrated circuit chips or components with the same function in the numerical control system to observe whether the fault phenomenon is transferred. Thereby, the fault location of the system can be quickly determined. This method is actually one of the replacement methods for spare parts. Therefore, the relevant precautions are as described in the spare parts replacement method.
6. Parameter inspection method It is well known that numerical control parameters can directly affect the performance of CNC machine tools. The parameters are usually stored in the bubble memory or stored in the CMOS RAM to be held by the battery. Once the battery is insufficient or due to external interference, etc., the individual parameters will be lost or changed, and the machine will not work properly. At this point, the fault can be eliminated by proofreading and correcting the parameters. When the machine tool is idle for a long time, if there is an abnormal phenomenon or a fault without an alarm, the relevant parameters should be checked and corrected according to the fault characteristics.
After long-term operation of CNC machine tools, due to the wear of mechanical transmission components, changes in the performance of electrical components, etc., it is also necessary to adjust the relevant parameters. Some machine tool failures are often caused by not modifying certain unsuitable parameters in time. Of course, these faults are all in the category of soft faults.
7. Measurement and comparison method When designing a printed circuit board, the CNC system manufacturer designs a plurality of detection terminals on the printed circuit board for the convenience of adjustment and maintenance. Users can also use these terminals to compare the difference between a normal printed circuit board and a faulty printed circuit board. The voltage and waveform of these measurement terminals can be detected to analyze the cause of the fault and the location of the fault. Even sometimes, "faults" can be artificially created on normal printed circuit boards, such as disconnecting or shorting, unplugging components, etc., to determine the cause of a real fault. To this end, the maintenance personnel should accumulate the correct waveform and voltage value of the key parts of the printed circuit board or the faulty parts at normal times. Because CNC system manufacturers often do not provide information on this.
8. Knocking method When the fault occurs in the numerical control system, if it is not present, the location of the fault can often be detected by tapping. This is because the numerical control system is composed of a plurality of printed circuit boards, each of which has a plurality of solder joints, and the boards or modules are connected by connectors and wires. Therefore, any solder joint or poor contact may cause a malfunction. When the insulator is used to gently tap the suspected spot with weak soldering and poor contact, the fault will definitely be repeated. #p#分页头#e#
9. Local heating method
After long-term operation of the CNC system, components must be aging and performance will deteriorate. When they are not completely damaged, the failures that occur will become unavailable sometimes. At this time, a hot hair dryer or a soldering iron can be used to locally heat up the suspected components and accelerate their aging to completely expose the faulty components. Of course, when using this method, you must pay attention to the temperature parameters of the components, do not burn the original good devices.
10. Principle analysis method According to the composition principle of the numerical control system, the logic level and characteristic parameters (such as voltage value or waveform) of each point can be logically analyzed, and then only measured, analyzed and analyzed by multimeter, logic pen, oscilloscope or logic analysis. Compare to locate the fault. Using this method requires maintenance personnel to have a clear and deep understanding of the principles of the entire system or each circuit.
11. Machine, electricity and liquid comprehensive analysis method CNC machine tool is a kind of high-machine, electric and liquid integrated product. It uses precision machinery, hydraulic technology, electrical technology, microelectronic technology, etc. It is necessary to analyze and diagnose the same fault from different angles of machine, electricity and liquid, which can avoid one-sidedness and less detours. Finally, it is confirmed which system of the machine, electricity and liquid has a problem, so that further diagnosis and troubleshooting can be performed in the corresponding system.
In addition to the above commonly used fault inspection test methods, there are also drawing method, voltage pull method, open loop detection method and so on. Including the above mentioned diagnostic methods, all of these inspection methods have their own characteristics. According to different fault phenomena, several methods can be selected at the same time for flexible application. Comprehensive analysis of faults can gradually reduce the fault range and eliminate faults faster. .
CNC machine tools are the crystallization of machine, electricity, liquid (gas), light and other technologies. Therefore, in the diagnosis, the exchange points of microelectronic systems and machines, electricity, liquid (gas), light, etc. should be tightly grasped. These nodes are The focus of information transmission will be of great help to the fault diagnosis of CNC machine tools. It can quickly determine the section where the fault occurred. If the fault may be on the side of the CNC system, plc, MT and hydraulic system, to narrow the inspection. range.
Once the fault location is found, but there are no spare parts available at hand, the transplant borrowing method can be used as an emergency measure. For example, if a component is broken (such as NAND gates or triggers, etc.), it is often only a certain path in the component, and other parts are still good. In the design of printed circuit boards, it is often only used as part of the components, not all of them are full. At this point, the remaining portion that is not used can be taken out for emergency use. The specific method is to cut off the damaged part of the pin (including the input and output feet), and then use the zone line to lead the signal input and output lines to the remaining component pins, so that the CNC machine tool can resume work as soon as possible.