Single-Point Diamond Crystal Tool for Precision Turning of Alumina-based Missile Domes

We propose to optimize our functionally-graded diamond/TiC/Ti composite turning tool, with an oriented diamond crystal at its cutting tip, specifically for machining alumina-based missile domes. The material is produced by pressure-assisted sintering of a mixture of the constituent phases in a single cost-effective operation. The diamond crystal is oriented for maximum resistance to abrasive wear. A demonstration of this concept has already been made, but much remains to be done to optimize the processing parameters and to scale the technology for processing domes. In the Phase I project, several conventional and novel diamond etching/polishing procedures will be used to achieve the desired oriented sharp cutting edge, which will be designed to satisfy the requirements for machining hemispherical and ogival shapes. It should be emphasized that the functionally-graded structure, comprising a sponge-like structure of micro-diamond crystals embedded in a TiC/Ti matrix phase, is the key to providing mechanical and thermal stability to allow the diamond tool tip to perform at its maximum potential. A successful Phase I demonstration project will quite naturally lead to a follow-on Phase II project, where the objective will be to machine a full-scale dome, with a base diameter of 130 mm, height of 195 mm, and a thickness of 2 mm. Phase I and II will be carried out in partnership with Ceranova--a company presently making near net-shape alumina.