An Experimental Investigation on Surface Roughness and Edge Chipping in Micro Ultrasonic Machining

Surface quality including surface roughness and edge chipping is a key process measure in micro ultrasonic machining (Micro-USM) as an efficient process for micromachining of hard and brittle materials. Process parameters such as ultrasonic vibration amplitude, static load, type of tool material, type and size of abrasive particles and slurry concentration can influence the surface quality. However, there is limited study on the parametric effects on the surface quality in micro-USM. The objective of this study is to investigate the effects of the workpiece material as well as process parameters including abrasive type, particle size and vibration amplitude on surface roughness and edge chipping in micro-USM. Silicon, alumina ceramics and soda-lime glass were selected as workpiece materials and polycrystalline diamond and alumina as abrasives. Particle size ranging from 0.3 to 3 μm and vibration amplitude ranging from 0.8 to 3 μm were selected in this study. Results indicate that workpiece material and vibration amplitude have significant effects on surface roughness. Workpiece material was found to be the most significant parameter with a percentage contribution of about 45 % in the variation of mean Ra, followed by vibration amplitude and particle size of about 28 % and 5% contributions, respectively. Results also show that alumina ceramic is a material capable of achieving better surface quality in micro-USM as compared to silicon and soda-lime glass.