Damage evolution in vibration assisted nano impact machining by loose abrasives at elevated temperatures: A numerical study

Abstract

In this research, a numerical study is conducted to investigate the effects of different machining parameters at elevated operating temperatures in a novel nanomachining process, Vibration Assisted Nano Impact machining by Loose Abrasives (VANILA). In this novel VANILA machining process, an atomic force microscope (AFM) is used as a platform and the nano abrasives slurry is injected between the vibrating AFM probe and the silicon workpiece. These nano abrasives are accelerated by vibration of the AFM probe and hit the workpiece and finally generate nano cavities on the top surface of workpiece. In this study, diamond particles are used as loose abrasives and the ductile mode machining is employed to describe the behavior of the brittle workpiece. The commercial finite element method (FEM) software package ABAQUS is employed to create numerical models for simulations. In addition to experimental validation, the FEM model is validated by comparing the numerical solutions against the analytic solutions to the impact problem between a semi-infinite stationary workpiece and a rigid particle at the impact speeds of 25 and 12.5 m/s. The percentage error is under 4.4%. This validated FEM model is then used to investigate the influence of the machining parameters (impact speed, impact angle, and friction coefficient between the nano particles and silicon workpiece) and the number of impact hits at elevated operating temperatures. It is found that the impact speed, impact angle, and friction coefficient between the silicon workpiece and nano particles have big influence on the damage volume and damage value (D) of the silicon workpiece at elevated temperatures. The research results show that by increasing the level of operating temperature, the machinability of silicon in the VANILA process can be improved substantially.