1, Spindle component failure

Due to the use of speed motors, CNC machine tool spindle box structure is relatively simple, prone to failure parts of the spindle internal tool automatic clamping mechanism, automatic speed control device. In order to ensure that the work or power failure when the tool clamp will not be white line loose, the tool automatic clamping mechanism using spring clamping, and with the travel switch to send a clamping or relaxation signal. If the tool can not be loosened after clamping, consider adjusting the pressure of the hydraulic cylinder to loosen the knife and the travel switch device or adjust the nut on the disc spring to reduce the amount of spring compression. In addition, spindle heating and spindle box noise problems, should not be ignored, at this time the main consideration is to clean the spindle box, adjust the amount of lubricant to ensure that the spindle box cleanliness and replacement of spindle bearings, repair or replacement of spindle box gears and so on.

2, Feed drive chain failure   

In the CNC machine tool feed drive system, commonly used ball screws, static screw nut vice, rolling guide, static guide and plastic guide. So the feed drive chain has a fault, the main reflection is the decline in the quality of movement. Such as: mechanical parts did not move to the specified position, running interruptions, positioning accuracy decline, backlash increase, crawling, bearing noise becomes larger (after the crash) and so on. For such failures can be prevented by the following measures:

(1) Improve transmission accuracy

Adjusting the preload of each motion vice, adjusting the loose link, eliminating the transmission gap, shortening the transmission chain and setting reduction gears in the transmission chain can also improve transmission accuracy.

(2) High transmission stiffness   

Adjustment of the screw nut vice, supporting parts of the preload and reasonable selection of the size of the screw itself, is to improve the transmission stiffness of effective measures. Insufficient rigidity will also lead to table or drag plate to produce crawling and vibration and cause reverse dead zone, affecting the transmission accuracy.   

(3) Improvement of motion accuracy   

Under the premise of meeting the strength and stiffness of the components, reduce the mass of moving parts as much as possible, reduce the diameter and mass of rotating parts, in order to reduce the inertia of the moving parts and improve the motion accuracy.   

(4) Guide rail

Rolling guide is more sensitive to stolen goods, there must be a good protective device, and rolling guide preload selection should be appropriate, too big will make the traction force increased significantly. Hydrostatic guide should have a set of filtering effect of good oil supply system.  

3, Automatic tool changer failure

Automatic tool changer failure is mainly manifested in the following: tool magazine movement faults, positioning error is too large, the robot clamping shank is not stable, the robot movement error is large, etc.. Failure will cause serious knife action stuck, the machine is forced to stop working.   

(1) Failure of tool magazine movement   

If the coupling connecting the motor shaft and the worm shaft is loose or mechanical coupling is too tight and other mechanical reasons, it will cause the tool magazine can not be rotated, at this time you must tighten the screws on the coupling. If the tool magazine does not rotate in place, it belongs to the motor rotation failure or transmission error. If the knife sleeve can not clamp the tool, it is necessary to adjust the knife sleeve on the adjustment screw, press the spring, tighten the top clamping pin. When the knife sleeve up / down is not in place, should check the position of the dial or limit switch installation and adjustment.   

(2) Tool change robot failure  

If the tool is not tightly clamped, drop the knife, then adjust the clamping claw spring, so that its pressure increases, or replace the robot clamping pin. If the tool can not be loosened after clamping, adjust the nut after the loose lock spring so that the maximum load does not exceed the rated value. If the tool is dropped when exchanging, it belongs to the spindle box does not return to the tool change point or the tool change point drift caused by the tool change, the spindle box should be re-operated to make it return to the tool change position and reset the tool change point.

4, The position of the axis movement travel switch pressure failure   

In the CNC machine tools, in order to ensure the reliability of automation Ding work, the use of a large number of detection of the movement position of the travel switch. After long-term operation of the machine tool, the movement characteristics of the moving parts change, the reliability of the travel switch pressure device and the travel switch itself the quality of the characteristics of the change in the performance of the machine has a greater impact. Generally, we should check and replace the travel switch at the right time to eliminate the impact of this type of bad switch on the machine tool.

5, Supporting auxiliary device failure   

Hydraulic system. Hydraulic pumps should be used variable pumps to reduce the heating of the hydraulic system. The filter installed in the tank should be cleaned regularly with petrol or ultrasonic vibration. Common failures are mainly pump body wear, cracks and mechanical damage, at which time it is generally necessary to overhaul or replace parts.   

Pneumatic system. Used for tool or workpiece clamping, safety guard door switch and spindle taper hole blowing chips in the pneumatic system, the water-splitting filter should be drained regularly and cleaned regularly to ensure the sensitivity of the moving parts in the pneumatic components. Valve heart action failure, air leakage, pneumatic component damage and action failure and other faults are caused by poor lubrication, so the oil mist should be cleaned regularly. In addition, should always check the air.