Improved machinability of SiC/SiC ceramic matrix composite via laser-assisted micromachining

Abstract

This study is focused on numerical modeling and experimental evaluation of laser-assisted micromachining (LAMM) of SiC/SiC ceramic matrix composite (CMC) materials. A novel experimental setup consisting of a fiber laser and the necessary optics, a three-axis CNC linear stage, and a high-speed spindle was used to implement the LAMM process. The laser-assisted micro-milling system provides unique micro-milling capabilities for flexible machining of very difficult-to-machine materials, such as ceramics, composites, and high-temperature alloys. The integrated high-power laser beam is flexibly focused on arbitrary positions around the cutting tool at a low incidence angle with a very small focused spot, thus making the system suitable for a wide range of micro-milling methods. Micro-end mills of cubic boron nitride (CBN) tools were used to perform slotting operations with and without laser preheating on CMC materials for comparative assessment. A three-dimensional (3D) transient finite-element-based thermal model was used to analytically predict appropriate process parameters on the basis of material removal temperature (Tmr). The effects of LAMM on the tool wear and tool life were evaluated experimentally. In addition, an economic analysis was carried out to compare LAMM of CMC materials with conventional micromachining methods.