CNC lathe processing is the most widely used method in our manufacturing industry.It improves production efficiency and improves the quality of our processed parts.Voltage plays a vital role in the use of CNC machine tools.The uncertainty of voltage is a problem encountered by our residents'power plants.The peak period of residents'electricity use is at night,and the various electrical appliances in the home will be unstable in the evening.The voltage of industrial power grids in China is also unstable and fluctuates greatly.As a result,the fault frequency of the power supply part of the numerical control system is relatively high,and it should be paid enough attention when repairing.The power supply is the energy supply part of the circuit board,the power supply is not normal,and the operation of the circuit board is inevitably abnormal.Let's take a look at the common faults of CNC machine power supplies.
1.The fuse is blown.If the fuse is black and spotted when it is blown,it indicates that the line has a serious short circuit.It is caused by obvious failure of high voltage filter capacitor breakdown and rectifier tube breakdown.If the fuse is not black,it is slowly blown and can be measured statically.Generally,one of the half bridges is broken or defective.
2.The fuse is continuous and the output has no voltage.In this case,first check if there is a DC voltage of 300V.If not,the fault occurs before the inverter;if there is 300V high voltage and no output,then the oscilloscope can be used to check whether the collector of the switch tube has a 20kHz waveform.If the switch is broken or does not rise.The open circuit of the high-frequency transformer can cause the inverter to stop.In addition,the inverter is normal but is protected by the overcurrent or overvoltage circuit of the latter stage,so that the output has no voltage.If the 12V main output power output is idling,it will cause over-protection and make the output no voltage.
3.The power supply output voltage is not accurate.Under normal circumstances,the allowable voltage range of the regulated DC voltage of each control system is within±5%of the rated value.If it exceeds this range,the voltage adjustment potentiometer can be adjusted.Adjust the main output voltage file to the standard value.If it is not possible to adjust to the standard value,the potentiometer may be broken or the regulator tube may be broken.If only a certain voltage deviation is large,it is likely that the rectifier diode is damaged.Try to exchange the same type of diode as much as possible.Sometimes the load capacity of the switching power supply is poor,and the output voltage is also reduced too much.This may cause the circuit operating point to deviate from the linear region due to parameter changes,such as the gain of the amplification section is reduced,and the detection circuit is in a nonlinear state.
4.The switching power supply emits a repeated special sound.This is usually caused by the low operating frequency.The oscilloscope can be used to detect the pulse width modulator,which is about 20 kHz during normal operation.If the capacity of the timing loop capacitor becomes larger,it will also cause the oscillation frequency to be too low,so that the power supply produces a special repeated sound.The switching power supply is not working properly.Replace the appropriate capacitor to restore its normal operation.
It is not only our machinery itself that affects the work of CNC machine tools.The influence of this power supply is also very large.Therefore,we must always pay attention to the power supply,ensure the normal operation of the power supply,and solve problems in time.