Thermal study of laser-assisted machining of silicon nitride.

摘要

Over the last decades Laser Assisted Machining (LAM) of hard materials has grown into a viable solution for the manufacturing industry. Interest in the machining of ceramics has grown due to the possibilities of LAM reducing tool wear and increasing productivity. The concept is based on heating the ceramic material into a soft phase that makes it much easier to machine. The other advantage this technology has over traditional grinding is that is possible to make complex shapes and even machine threads. While there has been research in LAM of ceramics such as Silicon Nitride, Zirconia, Alumina it often lacks comprehensive analysis for a particular laser source. In order for industry to adopt such a technology an optimized approach to providing results on ceramics is required. A few years ago as a result of ongoing research at NIU the commercial technology Easy to Machine Hard Materials (EMHM(TM)) was developed to address this issue. While research of Silicon Nitride, Zirconia, Alumina and Cemented Carbide are ongoing via EMHM the thrust of this research will be to provide a comprehensive approach and reduce the time required to optimize parameters for machining ceramics. The main issue to address for productivity in industry (when machining) is how to minimize tool wear (so tools last longer) while removing as much material as quickly as possible. This will obviously vary based on material and energy available. To experimentally carry all this work out would require a vast amount of resources and time. As such this proposal discusses the development of an easy to use ANSYS simulation program that will enable the user to see the surface temperature (which can translate to tool life) based on the feed rate, depth of cut, laser power and spindle speed. There are complex thermo-mechanical forces at play and so an optimized program is required to improve throughput of the analysis. We will develop the first generation ANSYS simulation which will help us verify experimental work we have done with the materials that have been researched via EMHM(TM).