Investigation of global thermal effect of large fused silica surface figuring using inductively coupled plasma

Abstract

Inductively coupled plasma (ICP) machining at atmospheric pressure has been used widely in fabrication of optical elements. However, the non-convergence caused by the global thermal effect is regarded as an inevitably issue for applying ICP to figure large fused silica optical surface. In this paper, according to the detailed investigation of the surface temperature distribution of the global thermal effect, a new method of round-trip repetitive tool path is proposed as a convenient way to balance the global thermal effect for making large fused silica surface error rapidly convergence. Experiment result shows that a work-piece with a size of 200 × 200 × 20 mm3 is successfully figured with this method. Result demonstrates that this method can realize rapid convergence for large fused silica optical surface. The presented study can provide convenient technical guidance of efficient fabrication for large fused silica optics by ICP surface figuring.