Precision electric spindlePlease avoid strong impact during use, especially at the end of the spindle and the front end cover, as it may damage the precision electric spindle bearings and spindle accuracy, resulting in a loss of spindle rotation accuracy. Before installation, it is necessary to confirm that the spindle motor is in normal condition, mainly due to its intact appearance and light and even rotation of the spindle. Use a 500V megger to check that the insulation resistance of the stator to ground is above 100M Ω. The fit tolerance between the outer diameter of the spindle motor sleeve and the clamping seat hole needs to ensure that the sleeve of the spindle motor can smoothly slide into the seat hole. Under no circumstances should a hammer or other tool be used to position the spindle, and the clamping force should not be too large, otherwise it will cause deformation of the steel ball raceway of the precision bearing, affecting the accuracy and service life of the spindle. After clamping, check that the runout of the centering surface of the taper hole at the front end of the spindle is not greater than 0.005mm, and that the spindle rotates gently and evenly.

Analysis of possible causes for accidental fracture of precision electric spindle:

The motor quality is not up to standard, and the spindle itself has defects;

The load is too high, exceeding the rated output power of the motor. During installation and commissioning, the main shaft of the motor is not concentric with the transmission shaft, resulting in the main shaft swinging and twisting.

According to the conventional processing method, a new motor needs to be replaced first. After installation, the workbench quickly moved and resumed normal operation. After running for a few hours, if the new motor spindle breaks again. Through careful observation, it was found that there were four connecting screws between the motor and the boring machine box. Due to the limitation of installation space, only the upper two screws were tightened, while the lower two screws were not tightened properly due to the inability to withstand force. It may be due to the main shaft and transmission shaft of the motor not being concentric, causing the main shaft to swing too much and twist off. After installing the new motor, tighten the four screws and test run it, then everything is normal.

If the motor spindle makes abnormal noise again after the machine tool has been working for several hours. Then eliminate the issues of motor quality and spindle misalignment, which could only be caused by excessive motor load leading to spindle fracture. Upon inspection of the transmission mechanism, no abnormalities were found. Upon checking the lubrication mechanism of the workbench, it was discovered that the guide rail surface was very dry and the lubricating oil was insufficient. Insufficient lubrication of the guide rail surface may cause an increase in friction force, resulting in insufficient motor output power to overcome the frictional load and causing the motor spindle to fracture.