Erosive smoothing of abrasive slurry-jet micro-machined channels in glass, PMMA, and sintered ceramics: Experiments and roughness model

Abstract

Abrasive slurry jet micro-machining (ASJM) was used to machine channels in glass, PMMA, zirconium tin titanate, and aluminum nitride. The channel roughness was measured as a function of the ASJM process parameters particle size, dose, impact velocity, and impact angle. The steady-state roughness of the channels was reached relatively quickly for typical ASJM abrasive flow rates. The roughness of channels having depth-to-width aspect ratios up to about 0.25 could be reduced by approximately 35% compared to the roughest channel by decreasing particle impact velocity and angle. However, machining at such conditions reduced the specific erosion rate by 64% on average. It was therefore quicker to post-blast reference channels (225nm average root mean square (Rrms) roughness) using process parameters selected for peak removal. It was also found that the roughness of reference channels could be reduced by about 78% by post-blasting using 3μm diameter silicon carbide particles at 15° jet incidence. The smoothest post-blasted channels had an Rrms roughness of about 23nm in glass, PMMA, and zirconium tin titanate, and 170nm in aluminum nitride. Computational fluid dynamics was used to predict the particle impact conditions that were used in a model to predict the steady-state roughness due to ductile erosion with an average error of 12%.