In the NC grinder processing industry, the common internal grinding includes bearing ring internal circle processing, gear internal circle processing, plunger pump cylinder internal circle processing, etc., so what are the common defects of the workpiece processed by these NC internal grinder? What is the reason for such defects? How to solve machining defects?
1 Out of roundness
Causes and solutions:
(1) The rotation accuracy of the spindle bearing at the head of the lathe is out of tolerance
(2) The accuracy of workpieces is out of tolerance, and the cutting edge is too large
(3) Workpiece clamping deformation
(4) Thermal deformation of workpiece
(5) Grinding wheel cutting performance is poor or not sharp
2 Cylindricity out of tolerance (taper)
Causes and solutions:
(1) The rotating axis of the workpiece is not parallel to the moving direction of the worktable
(2) The elastic deformation between the workpiece and the grinding wheel changes. Keep the grinding wheel sharp
(3) The reciprocating stroke and reversing dwell time of the grinding wheel are not properly selected. The reciprocating stroke should extend to the small end of the taper hole
3 Cylindricity out of tolerance (drum or saddle)
Causes and solutions:
(1) The motion accuracy of the worktable in the horizontal direction is not good
(2) The reciprocating stroke and reversing dwell time of the grinding wheel are not properly selected. Increasing the reciprocating stroke to both ends of the trapped hole can correct the waist drum defect, and reducing the reciprocating stroke to both ends of the hole can correct the defect
4 Surface burn
Causes and solutions:
(1) Contact area between workpiece and grinding wheel is too large and cooling is not sufficient
(2) The grinding wheel is too hard or the grain size is too fine
(3) The grinding wheel is too thin, not sharp or too blunt
(4) Too much cutting amount or too low workpiece speed
(5) Insufficient grinding fluid
5 Other surface defects (galling, scratches, etc.)
Causes and solutions:
(1) Cutting fluid is not clean
(2) The hardness of grinding wheel is too soft
(3) Workpiece is not suitable for abrasive wheel