Main cause
The center of the inner hole of the workpiece does not coincide with the turning center of the worktable of the machine tool
(1) About machine tools and fixtures:
1) Large radial runout of worktable
2) The spindle is worn or has large radial runout
3) Upper and lower thimbles have deviation or looseness
4) The fixture positioning end face is not perpendicular to the rotary center line of the worktable
5) Insufficient accuracy of workpiece clamping elements, such as washers and parallel caps
(2) Related parts:
1) Workpiece positioning hole diameter out of tolerance
2) The coaxiality of the outer circle and the inner hole is out of tolerance when the outer circle of the alignment workpiece is installed
3) Workpiece clamping rigidity difference
Resolvent
Focus on the control of the rotation accuracy of the machine set table and the correct installation of the workpiece
(1) For machine tools and fixtures:
1) Check and repair the table rotary guide
2) Reasonable use and maintenance of workpiece mandrel
3) Accuracy of post and upper thimble repaired
4) The fixture positioning end is not perpendicular to the rotation center line of the worktable
5) Improve the accuracy of workpiece clamping elements, such as washers and parallel caps
(2) Related parts:
1) Control the dimensional accuracy of workpiece positioning hole
2) Control the coaxiality error between the outer circle and the inner hole of the workpiece
3) The clamping force shall be applied to the parts with enough rigidity