Grinding and lapping of lens elements using computer-controlled machines

The pressing blank is first ground. During this work cycle, the first radius of both element surfaces is generated. Multi-axis (x, y, z axis) CNC (= ”computerized numerical control”) machines from renowned manufacturers are used for this purpose. These machines use two spindles. During the first step, approx. 1 mm of glass is removed with a deviation of 5 µm from the standard radius.

During the second step, i.e. lapping, approx. 1/10 mm of glass is removed with a deviation of 1 µm from the standard radius. Zeiss only uses environmentally sound grinding emulsions which are recirculated and used over an extended period of time.