| Breakdown Causes | Solutions |
| Wrong parameter setting | Check if fast movement speed is too fast, check the time constant of linear acceleration and deceleration, thread acceleration and deceleration constant, acceleration and deceleration lower limit of thread axes index, time constant of feeding acceleration and deceleration and the lower limit for low speed of feeding acceleration and deceleration |
| Electronic gear ration is not set up step angle is not modulated | If use 980T system or DA98 servo drive, check if electronic gear ration is correctly calculated and set up. If use step driver, check if the step angle and transmission ratio is correct |
| System or driver steps out | See if step motor or driver steps out through phase lamp or dial indicator. Servo drive can be check through pulse display on the driver or dial indicator; program dry run, see if there is any change in dial indicator after tool post returns to machining starting point; If no, check the parameter and the device |
| Line parameter of system encoder doesn’t match the encoder | There are 1200 and 1024 line parameter selection in 928TC, modify parameter based on spindle encoder line number and make sure system matches spindle encoder |
| Performance overload | There is upper limit for the multiplier of spindle speed and screw pitch. If exceed this upper limit, it may cause abnormal machining. Make sure all performance indexes are within reasonable range |
| Wrong operating mode or wrong programming format | Read operating instruction, get familiar with programming format and operating mode; wrong thread machining pitch for 928TA, 928TC (V2.13), add K value into thread machining instruction |
| Mechanical breakdown or motor failure | Measure if the location precision is qualified, measure screw clearance and see if use system parameter eliminate the clearance; check motor bearing and ballscrew, tightness of tool post location precision in overload situation, check spindle, fixture and tool installation, tool alignment and compensation |
| Spindle encoder signal line is interfered | Please use shielding signal line of spindle encoder and ensure reliable connection of shielding contactor between two ports |
| Unstable spindle speed | Eliminate external interference, check mechanical transmission stability |
| Mismatching between workpiece material and tool | Use matching tool to avoid sticking to the tool |