Design and evaluation of a thermal actuator for ultra-precision machining

摘要

Diamond milling of optical and freeform surfaces is usually considered to be a particularly slow machining process, as only one diamond tool with one cutting edge can be applied (i.e. fly-cutting). The reason lies in the tight tolerances of the machined surface, which are in the nanometre range. A novel attempt to enable an ultra-precise adjustment of multiple diamond tools is the use of controlled thermal expansion as actuating mechanism. The idea is to locally heat up the tool holder via a high-performance light source (i.e. IR-LED or laser) in order to induce a thermal elongation of the substrate material. This paper will present the initial design of such a thermal actuator on the basis of thermal and mechanical simulations. Furthermore, a first evaluation of such an actuator in a static test stand will be given.