Emergency treatment for the damage of the hottest

2022-09-19
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Emergency treatment of NC module damage

after the NC system and servo module are damaged, the module is usually replaced to solve the sudden failure on site. However, in the case of lack of spare parts, the maximum range is almost unused. Compared with the frequently used range, sometimes flexible emergency methods are adopted to restore the CNC machine tool to work, which not only ensures the normal operation of the equipment, but also shortens the downtime of the machine tool and saves maintenance costs

example 1: Equipment Overview: machine tool model: ch097 (produced by Great Wall Machine Tool Factory)

fault phenomenon of CNC lathe: the spindle motor sometimes responds slowly

diagnosis: according to the operator, the machine tool has a fault for a period of time, sometimes good and sometimes bad. When the fault occurs, the spindle motor does not rotate, and the spindle starts to operate in about ten seconds. It can last until the whole part processing is completed, and no alarm number is generated in the whole process

first of all, in the og state, start the spindle, and occasionally the spindle runs slowly. Check the corresponding input and output points according to the PLC program. After inspection, the tool holder clamping switch, spindle clamping pressure switch, tailstock switch, etc. are normal, and q100.6 has been output as 1, so check the spindle module, measure the analog input terminals 56 and 14, The voltage is 3.5V (it varies depending on the set speed of the system spindle. However, there is no 12V voltage at pin 65 of the X431 plug enable signal, and the spindle can operate by shorting the 65 and 9 ends of the X431 plug, which indicates that the measuring plate of the system may be damaged. It is confirmed by exchanging with the measuring plate of other machine tools. The model of the measuring plate is: 6fxh214ba02. The wiring principle is shown in Figure 1: because the spindle of the measuring plate simulates FTE constant, and the functions of the other two axes are normal, it is only the main shaft The enabling signal is poor, and the measurement of China's plastic extruder market has made great progress and breakthrough. The price of the board is more than 10000 yuan, so the following emergency inspection PLC program is adopted. 4. After adjusting the hardness tester, find the output point of the redundant PLC. After finding q2.4 is not used, modify the PB3 section of the PLC program, and insert q2.4 after the output point q100:6 Remove the original enable signal wire at the spindle module and remove q2 4. The output is led to 65 of the spindle module X431. After the above changes, the spindle function returns to normal. The improved circuit is shown in Figure 2: produced by Cheng machine tool factory) fault phenomenon of CNC lathe: spindle motor short circuit diagnosis: when the machine tool works normally, the spindle module and power module are damaged at the same time due to the damage of the spindle motor power line. After insulating the spindle motor line, remove the spindle module and power module and replace them with modules in the same model machine tool. The machine tool works normally, and the servo and CNC systems are normal, The model of the power module is 6sc61122va01, and the model of the spindle module is 6sc6113ohaoo, which can be replaced by the corresponding 611A module. However, after inquiry, the total price of the two modules is about 50000 yuan, and the supply cycle is long, which affects the normal production of the workshop. Therefore, we have adopted the scheme of replacing it with a frequency converter: after the calculation of the power of the servo clock (the power selection is based on the Siemens drive Planning Manual of the motor power of X and Z axes), 6snu451aa010aa1 (10/25kw) power module is used to supply the servo shaft, and the wiring method is exactly the same as that of 6sc series module; For the frequency converter, according to the motor power and other parameters, combined with the use of the machine tool, we plan to adopt the vector frequency converter for transformation

the requirements for frequency converter are: 1. Be able to control the motor by selecting vector control mode to ensure the constant torque of the motor at low speed

2. The analog input controls the speed and rotation direction of the motor

3. Strong anti-interference ability, small external interference and ultra-low noise

after comparing the cost performance of various brands of frequency converters, the Japanese Mitsubishi sagittal frequency converter fra54015k-ch (15kw) is used to replace the yuan spindle module, and the cost of the above two items for the spindle motor is still about 27000 yuan

since the spindle position encoder is installed at the tail of the spindle and is directly connected to the system, it can be changed

implementation: remove the original power module and install a new power module and frequency converter. Because the new power module and frequency converter are small, they can be directly installed in the electric box, and the new power module does not need to be re perforated. The schematic diagram of the connection principle before the transformation is shown in Figure 3: connection and debugging: after the frequency converter is connected with the spindle motor, it can be powered on for debugging. First, the CNC system control signal and parameter number set value parameter 7113 is applicable to the motor, and the constant torque motor is selected/V selection, select 0- V, the polarity is reversible and effective. 809 motor capacity, advanced flux vector control. 814 motor pole nine, advanced flux vector control. The rated voltage of 83290 motor shall be set to be less than 290 Relevant parameter setting: the analog quantity is not connected with the frequency converter, and the spindle motor of the frequency converter is debugged separately. According to the frequency converter and spindle motor, the relevant parameters are input according to the operation manual of the frequency converter, and the parameters of the frequency converter and motor are automatically optimized, and the spindle motor is commissioned

after the above parameters are set, adjust the parameter No. 96 "automatic adjustment setting/state", so that the frequency converter can automatically measure the motor, so that the frequency converter can match the motor better

after the commissioning of the frequency converter and the spindle motor, connect the enabling signal of the numerical control system to the frequency converter with analog quantity, test run the spindle motor, and properly adjust the system parameters to optimize the linearity of the spindle speed

precautions: the most critical thing in the whole transformation process is the interference of the frequency converter to the CNC system, including the interference to the servo shaft. This is the key to the success or failure of the whole transformation. The frequency converter is not connected with the numerical control system (the enable and analog quantities are not connected). During the online commissioning of the frequency converter and the spindle motor, it is found that the frequency converter interferes with the servo module. Sometimes the digital display of the x-axis and z-axis drive module is abnormal, which must be eliminated by the reset key on the system operation panel. Therefore, we have taken the following measures: 1. The input end of the power supply (see the frequency converter control circuit) to limit the harmonics on the power supply, Reduce the conduction and radiation interference of the inverter

2. The control line adopts shielded wire, the connection between the motor power line and the frequency converter adopts cultured cable, and the shielding layer is grounded at both ends. At the same time, use a short thick wire to connect the ground wire

3. The connection between the numerical control system and the frequency converter shall be isolated as far as possible

4. Check whether the arc extinguishing function of the contactor in the electric box is normal. Replace all AC contactors with R-C suppressors that have heating and bulging

after taking the above measures, the interference is completely eliminated, the frequency converter works normally after being connected with the numerical control system, and there is no fault in the order of 10% ~ 15%, 30% ~ 40%, 45% ~ 55% of the weight reduction of the vehicle after continuous use for half a year

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