An optical component usually start with a glass blank disk of an appropriate type and size. The glass blank disk is aligned and securely mounted onto the generator spindle in preparation for the shaping operation. Some important  considerations have to be taken into account such as: the amount of material that is to be removed from the first side depends on whether the required surface profile is flat or spherical.  For a spherical surface a special diamond impregnated cutting tool is used to produce the desired surface shape. This tool is pre-set to a specific angle for the shape that is needed.

A specific amount of material is removed from the glass blank with each rotation of the generator spindle. The amount of material removed is carefully controlled for the first side of the optical component so as to assure that the second side can be made to the required shape and dimensions. 

To avoid going under the thickness tolerance a small allowance is added to the thickness on the second side. This compensates for the material removed during the grinding and polishing operations.

The surface finish of the optical component continually gets smoother with each of the following grinding and polishing operations.

If you would like to know more about the next operations go to Grinding.