Laser Assisted Machining Applied to Rifling of Ceramic Barrels

Ceramic barrels have found little application as their extreme hardness make them quite brittle and difficult to machine. Grinding and diamond machining have found some success but both yield very low material removal rates and can induce defects. To address this problem Nanohmics Inc. and Dr. Y. C. Shin of Purdue University propose to apply the recently developed technique of laser assisted machining (LAM) coupled with a specially designed tooling system to develop a means of rifling ceramic barrels. In LAM a laser provides an intense localized heat source to the rotating workpiece just prior to the cutting region. The low thermal conductivity of ceramics allows excellent control of local temperatures (both in surface extent and in depth) and, for certain ceramics, leads to a reduction in strength in the heated regions and an increased machinability. Dr. Shin has been leading the commercial development of LAM and has pioneered processing methodologies for several different ceramic compounds1-3 (e.g. Si3N4, mullite and partially stabilized zirconia. In addition, Nanohmics personnel have extensive experience in specialized tooling applications and will apply this expertise to adapt the LAM process to the production of a cost effective method of rifling ceramic barrels.