The processing of optical parts is divided into hot machining, cold machining and special machining. Cold processing is sawing, rough grinding, fine grinding, polishing and centering grinding edge with loose or solid abrasive. Special machining only changes the properties of the polished surface without changing the shape and size of the optical parts.The main tasks of each process of cold machining are as follows:
- Rough grinding (cutting) process: the process of making a part have basically accurate geometry and size.
- Fine grinding (rough grinding) procedure: to prepare the parts to the specified dimensions and requirements.
- Polishing (fine grinding) process: it is to make the surface of the part bright and achieve the required optical precision.
- Centering process: the outer circle of the lens relative to the optical axis.
- Cementing process: different optical parts are glued together, so that the optical axis overlap or by a certain direction.
The three basic processes of the current processing technology of spherical optical parts are as follows:
- Mill (cutting) based on the fan method
- High speed rough grinding of pressure transfer principle
- High-speed polishing of pressure transfer principle.
The milling (cutting) principle of the model method, although the processing efficiency is higher, but its influence error factors are more, to achieve higher precision and roughness more difficult.The high speed rough grinding and high speed polishing of the quasi-spherical center of pressure transfer principle can ensure the precision of the part.The precision of the dressing surface needs the operator’s experience and skill, and needs the repeated dressing.