MANUFACTURING TECHNIQUES FOR COMPLEX SHAPES WITH SUBMICRON ACCURACY

In the introduction, applications of parts with submicron accuracy are shown. The demands with regard to the accuracy of these parts are discussed. The main characteristics of various precision-machining processes are outlined. Specific advantages and problems associated with these processes are indicated. Different aspects of part accuracy and surface quality are treated in more detail. Many parts with submicron accuracy have an optical function, and special attention is paid to the requirements with regard to form accuracy and roughness of optical elements. A distinction is made between machine- and process-related problems. The machining operation is introduced as an overall system containing the machine and process as interacting subsystems. The author also discusses techniques used to minimise machine-related part errors in the design of precision machine tools. The sensitivity of various processes to particular types of machine- and environment-induced disturbances is outlined. Developments in the investigations of material removal mechanisms are described. These include the mechanical modes of material removal on which diamond turning, grinding and polishing (to some extent) are based as well as the basic chemical phenomena in processes involving etching. After these descriptions of the machine and process aspects, the influence of the interaction between these subsystems on the surface quality is outlined. The emphasis is on the coupled dynamic behaviour in diamond turning and grinding. The author concludes with an 'executive summary' outlining the areas in which significant progress has been made in recent years and the main unresolved problems.