In the grinding process, the working surface of bearings is ground by high-speed rotating grinding wheel. Therefore, if the equipment is not operated and adjusted according to the operation instructions during grinding, various roughness defects will appear on the working surface of bearings, which will affect the overall quality of bearings.

There are straight wavy marks on the workpiece surface

We cut a cross section of the vertical axis line of the grinding workpiece and magnify it. It can be seen that its periphery is similar to a sine wave. So that its center along the axis line without rotation and translation, the trajectory around the sine wave is the waveform cylinder, also known as this polygon.

The reason for the straight waveform is the vibration caused by the movement of grinding wheel relative to the workpiece or the periodic change of grinding pressure of grinding wheel on the workpiece. This vibration may be forced or self-excited, so there is often more than one direct wave frequency on the workpiece.

► The specific reasons for the straight waveform trace are as follows:

1. The grinding wheel spindle clearance is too large;

2. Hardness of grinding wheel is too high;

3. Poor static balance of grinding wheel or dull grinding wheel;

4. The workpiece speed is too high;

5. The transverse knife is too large

6. The grinding wheel spindle bearing is worn and the fit clearance is too large, resulting in radial runout;

7. Grinding wheel pressing mechanism or working table “creeping”, etc.

The surface roughness is not up to the requirements

There are standards and technological requirements for surface roughness of bearing parts, but in grinding and superfinishing process, due to various reasons, it often fails to meet the requirements.

► The main reasons for the workpiece surface roughness not meeting the requirements are:

1. The grinding speed is too low, the feed speed is too fast, the feed quantity is too large, and the grinding time without feed is too short;

2. The workpiece speed is too high or the workpiece shaft and sand wheel shaft vibration is too high;

3. The grinding wheel particle size is too coarse or too soft;

4. The dressing speed of grinding wheel is too fast or the gap of dressing mechanism is too large;

5. The diamond of dressing grinding wheel is not sharp or of poor quality;

6. The quality of super-fine oilstone is not good, and the installation position is not correct;

7. The quality of ultra-refined kerosene cannot meet the requirements;

8. Ultra fine time is too short, etc.

If you have any questions,pls feel free to contact  us.

e-mail:bearing6@hyzcgroup.com