Laser-Assisted Machining of Reaction Sintered Mullite Ceramics

Abstract

The present study focuses on the evaluation of the laser-assisted machining (LAM) of pressureless sintered mullite ceramics. Due to mullite’s low thermal diffusivity and tensile strength, a new method for applying laser power is devised to eliminate cracking and fracture of the workpiece during laser heating. The LAM process is characterized in terms of cutting force, surface temperature, chip morphology, tool wear, surface roughness and subsurface damage for a variety of operating conditions. Estimated material removal temperatures and the ratio of the feed force to the main cutting force are used to determine material removal mechanisms and regimes for brittle fracture and semi-continuous and continuous chip formation. Surface roughness and subsurface damage are compared between typical parts produced by LAM and grinding. Tool wear characteristics are investigated for variations in laser power, and hence material removal temperature, during LAM of mullite with carbide tools.