CNC lathe manufacturers tell you that when CNC lathe presents the following fault phenomenon, we should first consider whether it is caused by the fault of the detection equipment in the servo system, and correct analysis to find the fault part.
1. Display servo system alarm
Pay attention to this moment:
(1) The axial pulse encoder responds to signal disconnection, short circuit and signal loss, and uses oscilloscope to measure signal of phase A and phase B to see whether it is normal.
(2) The internal defects of the encoder, the formation of the signal can not be correctly accepted, check its pollution, too dirty, deformation, etc..
2. Abnormal speed of mechanical movement (flying car)
To repair such faults, we should check the working conditions of the azimuth control unit and the speed control unit together, and also check the points:
(1) Whether the wiring of pulse encoder is wrong, check whether the wiring of encoder is positive reaction, and whether phase A and phase B are connected in reverse.
(2) Whether the coupling of pulse encoder is damaged, if damaged, replace the coupling.
(3) Check whether the terminal of the velocimeter generator is connected inversely and the excitation signal line is connected incorrectly.
3, mechanical vibration (acceleration/deceleration)
Common causes of such problems include:
(1) The pulse encoder is defective. At this moment, we should check whether the voltage on the reaction line terminal on the speed detection unit drops at a certain point. If there is a drop, it indicates that the pulse encoder is defective and the encoder should be replaced.
(2) The pulse encoder cross coupling may be damaged, resulting in the shaft speed is not synchronized with the detected speed. Replace the coupling.
(3) The velocimeter generator is defective, repaired and replaced. In repair practice, there are many problems of speed measuring brush wear and jam resistance. Should disassemble the speed machine, be careful to remove the brush, polish it on fine sandpaper a few times, clean the dirt of the commutator together, and then install it from scratch.
4. Vibration when coordinate axis is fed
During maintenance, we should check whether the motor coil is short-circuiting, whether the connection between the mechanical feed screw and the motor is outstanding, and whether the whole servo system is stable, check whether the pulse coding is outstanding, whether the coupling is stable and reliable, and whether the speed detector is reliable.
5, the spindle can not be directional movement or directional movement is not in place
Maintenance of such problems, should be in view of the directional control circuit setting adjustment, view the directional board, spindle control of the printed circuit board adjustment together, should check the azimuth detector (encoder) is bad, at the moment generally to measure the output waveform of the encoder, through the discrimination of output waveform is normal to determine the quality of the encoder. (Repair personnel should pay attention to record the normal output waveform of the encoder when the equipment is normal, so as to check the fault.)
6. Present NC fault alarm
NC alarm due to program fault, operation fault caused by the alarm. Such as FAUNUC6ME system NC alarm 090.091. NC alarm is presented, which may be caused by main circuit fault and low feed speed. Together, and possibly:
(1) Poor pulse encoder.
(2) The power supply voltage of the pulse encoder is too low (at this moment, adjust the power supply voltage of 15V to make the voltage value on the +5V terminal of the main circuit board within 4.95-5.10V).
(3) There is no input pulse encoder of a turn signal and can not normally perform the reference point back.
