7 Causes of Common Errors in Machining

The quality of finished products is closely related to the quality of equipment. Under the long-term non-stop production of machines, the wear of tools, fixtures, and workpieces will affect the "machining accuracy" and eventually lead to errors in the finished parts.

TMT will take you to understand what are the main factors that are prone to errors during processing?

1. Tool wear
   Tool wear is inevitable during the cutting process, which causes changes in the size and shape of the workpiece.
2. Fixtures positioning
   The function of the fixture is to fix the workpiece in the correct position, so the geometric error of the fixture has a great influence on the machining error. (especially the position error)
3. Stress deformation of cutting condition
   ➤Workpiece rigidity: If the rigidity of the processed workpiece is "lower" than machines, tools, and fixtures, under the action of cutting force, the influence of deformation caused by insufficient rigidity on machining errors will increase.
   ➤Tool rigidity: The rigidity of the outer turning tool on the processing surface is very high, and its deformation can be ignored. But the rigidity of the tool shank is not good for boring the inner hole with a small diameter, and the machining accuracy will be greatly affected after deformation by force.
4. Thermal expansion error
   The thermal expansion error of the process system has a great influence on the machining error, especially in precision machining and large-scale machining, the error caused by thermal expansion error can sometimes account for 50% of the total error of the workpiece.
5. Adjustment error
   In each process of machine processing, the cutting conditions must be adjusted. However, the adjustment cannot be absolutely accurate, so there are errors. In the cutting conditions, the mutual position accuracy of the workpiece and the tool on the machines is guaranteed by mutual adjustment. When the original accuracy of machine tools, tools, fixtures and workpiece material meets the requirements and does not consider dynamic factors, the adjustment error will play a decisive role in processing.
6. Measurement
   When the parts are measured during or after processing, the measurement accuracy will be directly affected by the measurement method, measuring equipment accuracy, workpiece and subjective and objective factors.
7. Internal stress
   The stress that exists inside the part without external force is called internal stress. Once internal stress is generated on the workpiece, the metal of the workpiece will be in a high-energy unstable state, accompanied by deformation, so that the workpiece loses its original processing accuracy.

After understanding the causes of these common errors, you can quickly find the corresponding method according to the machine and cutting status, and maintain the processing quality of the machine and reduce the product defect rate through regular inspection, equipment maintenance, and tool replacement.
If you have any questions about the above information, please contact us, TMT will provide you with more detailed instructions and suggestions!