CNC machining center is a CNC machine tool with the function of automatic tool change. The difficulty of tool removal of CNC machining center is one of the common failures. However, due to its complex structure, involving electrical, mechanical, pneumatic, hydraulic, etc., any loop link failure will cause the tool removal failure of the machine tool. Taking the tool removal failure of VMC650 CNC machining center as an example, the following is a brief introduction to the causes of tool removal failure and maintenance plan, hoping to help you:
1. Fault characteristics
There is a VMC650 CNC machining center. It is very difficult to change the tool. When changing the tool, it is necessary to use a copper hammer or other metal to strike, and the tool handle can be removed only after vibration. In this way, there will be potential safety hazards. Long term impact will cause damage to the tool handle and affect the spindle accuracy.
2. Troubleshooting and inspection steps
(1) Check the hydraulic cylinder and the end of the piston rod for wear, which causes insufficient downward travel of the pull rod to push the pull pin.
(2) Check the diameter and height of the pull pin, and check whether the pull pin is reliably connected with the thread of the tool handle, otherwise it is easy to cause difficulty in removing the tool.
(3) Check the deformation and wear of the spring and sleeve, which is the main reason why it is difficult to disassemble the cutter on the CNC milling machine or machining center. In the process of NC machine tool processing, due to the worker's proficiency and technical level, there is an inevitable phenomenon of tool breaking, which causes the deformation of spring and sleeve and makes it difficult to disassemble the tool. In case of wear and deformation during inspection, it shall be replaced in time. When replacing, ensure the consistency with the size and shape of the original parts.
(4) The internal surface of the 7:24 taper hole should be maintained regularly, and there should be no bumping, pulling or rusting, otherwise it is easy to cause the radial runout and axial runout of the tool handle to exceed the tolerance, which will affect the machining accuracy.
(5) Check whether there is strain on the inner hole surface and outer surface of the sleeve. If there is slight strain, use an oilstone to repair it. If the strain is serious, replace the parts. The main reasons are: the dirt in the spindle tool mounting hole is not completely removed, or the compressed air pressure is insufficient, which can not play a role in removing dirt.
3. Troubleshooting results
Through dissection and inspection of this machining center, it was found that the causes of the failure were: after the travel switch was used for a period of time, the fastening screws were loose, which led to inaccurate positioning of the travel switch, insufficient downward distance of the hydraulic cylinder piston, insufficient downward pressure of the pull rod on the knife handle pull nail, and difficult knife folding. After we readjusted the position of the travel switch controlling the downlink, the problem was completely solved and the fault disappeared. These problems require us to do a good job in the maintenance of all aspects of the CNC machining center in daily use, reduce the occurrence of failures, and improve our processing efficiency and safe operating environment.
