A review of few unconventional machining processes based on the concept of velocity shear instability in plasma

Abstract

In this article, published work on unconventional machining process, plasma spray process, plasma etching and abrasive jet machining has been summarized. In unconventional machining process, based on the concept of velocity shear instability in plasma, the material is removed from metallic surface by the impact of ions. Single-crystal silicon surface roughness (up to nanometer sizes) induced by gas plasma in plasma etching based on the concept of velocity shear instability in plasma has been achieved. The material removal from metallic surface can be explained on the basis of erosion phenomena. Momentum transfer from ions to abrasive particles accelerates micron-sized abrasive particles. In this process, material removal from metallic surfaces varies from a few milligrams to a few grams per second. Plasma spray process is based on the concept of velocity shear instability in plasma. In this process, heat generated in plasma and velocity of ions is used to develop high quality surface. Actually, the velocity of ions depend upon different parameters like magnetic field, homogenous D.C electric field, shear scale length, temperature anisotropy, heterogeneity in D.C electric field, density gradient, etc. Therefore, a combination of aforementioned parameters is selected to suit the requirement.