Experimental Study of the Impact of a Vibrating Wire on Free Abrasive Machining as Correlated to the Modeling of Vibration Subject to an Oscillating Boundary Condition

Abstract

In this paper, we study experimentally the impact of a vibrating wire on the free abrasive machining (FAM) process in removing material from the surface of brittle materials, such as silicon. An experimental setup was designed to study the FAM process on silicon substrate surface by using a slurry-fed wire with a periodic excitation. An analytical solution of a wire moving axially, subject to an oscillating boundary condition with damping from abrasive slurry, was derived based on the partial differential equation of motion. Experiments were conducted on the apparatus using a wire with an oscillating boundary. It was found that the amplitudes of vibration were larger at the side of the oscillatory boundary, which caused more FAM interaction near the edge of the oscillatory boundary with larger material removal that was measured and validated. Furthermore, experiments were conducted to elucidate the effectiveness of brittle material removal using FAM with abrasive grits: (i) under dry condition, (ii) with water, and (iii) with abrasive slurry. Experimental results showed that the vibration of wire resulted in plastic deformation on the surface of silicon wafer. The abrasive grits in slurry driven by a vibrating wire generated material removal through observable grooves and fractures on the surface of silicon due to FAM in just a few minutes. The grooves from FAM process is an outcome of brittle machining through fracture formation and concatenation, generated by the indentation of abrasive grits on the silicon surface.