Common Quality Problems And Causes Of Bearing Ring Surfaces

1. Poor surface roughness

Causes: Insufficient super-finishing time, too high grinding stone pressure, relatively high grinding stone vibration frequency, and too low speed of fine-super-finishing workpiece.

2. Hyperseminoma

The raised particles of different sizes and shapes formed on the machined surface after super-finishing are mainly due to the fact that the grinding particles are sintered on the machined surface under the action of instantaneous high temperature and high pressure. Its existence increases the vibration value of the bearing and reduces the vibration value of the bearing. increases the service life of the bearings.

Cause: The grindstone pressure is too high. The surface roughness value before super-finishing is too high, the workpiece speed is too high, the cooling of the cutting lubricant is insufficient, and the residual magnetism of the bearing ring grinding process is too large.

3. Silk

Net-like scratches on the machined surface after super-finishing.

Cause: The grindstone has too many impurities and the particle size is uneven; the cutting fluid has impurities and insufficient flushing.

4. Comet traces

During the super-finishing process, due to individual larger diamond particles falling off or blocking the recesses on the surface of the workpiece, comet marks are formed along with the super-finishing pressure and the rotation of the workpiece.

Cause: Choose the grindstone correctly and reduce the pressure on the grindstone.

5. Grinding wheel flower

Reasons: The grinding wheel pattern is too thick during surface grinding, the workpiece speed is too high during rough and super finishing, the time for rough and super finishing is too short, the grinding stone pressure is too small during rough and super finishing, and the grinding stone swing angle is too small.

6. The axial movement of the end face is too large

Cause: The eccentricity of the workpiece is too small, resulting in unstable rotation of the workpiece, large radial runout, the swing center of the grindstone does not coincide with the curvature center of the workpiece raceway, and debris on the end support surface when the workpiece is positioned, resulting in axial movement of the end face. The momentum is too large, the geometric accuracy of the grinding process is poor, and the workpiece has been repaired many times.

7. Poor roundness and waviness

Causes: The eccentricity of the workpiece is too small; the rotation speed of the precision and super-finishing workpiece is too high, causing vibration of the machine tool; the width of the grinding stone is not enough, and the wrap angle is too small; the support angle when positioning the roller is too small and cannot drive the ferrule to rotate normally; grinding Process roundness and corrugation are too large.

8. The curvature of the ball bearing raceway is not good after super-finishing.

Cause: The swing center does not coincide with the curvature center of the raceway: the width of the grindstone is too large and the wrapping angle is too large.