In the optical cold working process, the precision control of surface curvature radius of fine grinding is very important, which has the same important technical position as the fine grinding process of optical glass.

In optical glass processing, rough grinding is carried out by contacting the grinding dish with the lens surface. Although the radius of curvature of the surface of the grinding dish is well modified at the beginning of use, the grinding dish also continues to wear out with the grinding of the lens, which may not guarantee the machining accuracy of the lens gradually. If the accuracy of curvature radius is not enough, it will directly affect the qualified rate of the finished glass lens. If the size is small, it will result in a waste of materials.

Through continuous experiments, it is believed that the following steps should be taken to keep the curvature radius of coarse grinding dish unchanged or less changed:

1. Should be a reasonable choice of jig, usually located in the above jig is always smaller than the size of the following jig, this is because the above jig to swing the relationship. If the size of the upper fixture is the same as the size of the lower fixture, the edge grinding opportunity of the upper fixture is too few, and the upper fixture has the trend of warping.

2. If the size of the upper fixture is too small than the size of the following fixture, more than the specified data, the upper fixture in the swing process, the edge is not exposed, the edge of the upper fixture will wear too much, the upper fixture has the trend of collapse.

3. If the size of the upper fixture is larger than the size of the lower fixture, when swinging, the edge of the lower fixture will expose too little opportunity, the edge of the lower fixture is worn too much, and the following has the trend of collapse.
The above is the method to maintain the accuracy of surface curvature radius in cold working of optical glass.