Common faults of linear guide rail

 Linear guide rail is attributed to precision parts, except for the inevitable defects caused by improper operation of operators, but if it is not cleaned, there will be some defects caused by external factors or human factors, and these defects will be repaired.

What kinds of repaired defects are there for linear guide rail ?

(1) Repair of motor overheating alarm
Defect: X-axis motor overheat alarm
Analysis and treatment process: There are many reasons for motor overheating alarm, except the servo unit itself, perhaps the cutting parameters are unreasonable, or maybe there is a problem in the transmission chain. However, the defect of the machine tool is that the linear guide strip and the gap of the guide rail are too small and too tight. Loosen the locking screw of the insert, adjust the locking screw of the insert, make the moving parts move freely, ensure that the 0.03mm feeler gauge is not inserted, and then lock the locking screw. Defect cleaning.

(2) Significant mechanical vibration defect repair occurred at the stroke terminal.
Defect: During the operation of a machining center, a significant mechanical vibration defect occurs when the X-axis displacement of the workbench approaches the end of the stroke, and the system does not give an alarm when the defect occurs.
Analysis and treatment process: because the system does not give an alarm when the defect occurs, but the defect is obvious, the confessed defect should be on the side of the X-axis servo motor and the screw drive chain through the exchange method. For the difference of motor defects, the elastic coupling between the motor and the ball screw can be disassembled, and the motor can be checked by electrifying alone. The results show that there is no vibration phenomenon when the motor works, and the obvious defect lies in the mechanical transmission part. Disengage the elastic coupling, roll the ball screw with a wrench to check the feel; After hand feeling inspection, it is found that when the X-axis displacement of the workbench approaches the end of the stroke, the resistance is obviously increased. Dismantle the workbench to check, and find that the ball screw is not parallel to the guide rail, which causes the vibration phenomenon in the process of mechanical tumbling. After careful repair and adjustment, it is installed from the beginning and the defects are cleaned.

(3) Repair of defects caused by loosening of ball screw nuts.
Defect: The machine tool’s Z-axis operation (square ram is Z-axis) shivers, and the alarm No.123 appears instantly; Intermittent operation of machine tools.
Analysis and processing process: The reason for the alarm No.123 is that the stalking fault exceeds the value specified in the machine tool data TEN345/N346.

There are three possible reasons for this phenomenon:

① The detection equipment of the azimuth measurement system is poorly connected with the mechanical displacement part.
② The transmission part is vacant.
③ Azimuth closed-loop amplification factor KV does not match.
After detailed examination and analysis, it is initially concluded that the latter two reasons cause load disturbance during the operation of square ram (Z axis) and form azimuth closed-loop vibration. According to this discrimination, we first modified the machine tool data TENl52 which set the Z-axis KV coefficient, and changed the original value S1333 to S800, which reduced the amplification coefficient and contributed to the stability of azimuth closed loop: after the trial operation, it was found that although the vibration phenomenon was obviously weakened, it was not completely eliminated. This shows that the possibility of mechanical transmission showing vacancy increases; Maybe the ram insert is loose, or the ball screw or nut moves. After all, the defect source is found out by choosing the method of first easy and then difficult, first negative from outside to inside. The back cap of the ball screw nut is loose, which makes the transmission appear vacant. When the Z axis moves, the load disturbance caused by the vacant position causes the azimuth closed-loop vibration and shivering phenomenon. Tighten the loose back cap, adjust the empty space, and restore the machine tool data TENl52 to the original value, and then eliminate the defects.
(5) Repair the defects with unqualified positioning accuracy of machine tools.
Defect: When working in a machining center, when the Y-axis displacement of the working table approaches the end of the stroke, the reverse vacancy of the lead screw is obviously increased, and the positioning accuracy of the machine tool is unqualified. Analysis and treatment process: the defective part is obviously on one side of the X-axis servo motor and screw drive chain; Disassemble the elastic coupling between the motor and the ball screw, and roll the ball screw with a wrench to check the feel. After hand feeling inspection, it is found that when the X-axis displacement of the workbench approaches the end of the stroke, the resistance is obviously increased. Dismantle the operating table for inspection. It is found that the parallelism of Y-axis guide rail is severely out of tolerance, which leads to a significant increase in resistance in the process of mechanical tumbling, elastic deformation of ball screw, increased reverse vacancy and unqualified positioning accuracy of machine tool. After careful repair and adjustment, it is installed from the beginning and the defects are cleaned.