Title: A study of chip formation in ductile-regime machining of 6H silicon carbide by molecular dynamics

Authors: Gaobo Xiao; Suet To; Guoqing Zhang

Addresses: Partner State Key Laboratory of Ultra-precision Machining Technology, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong ' Partner State Key Laboratory of Ultra-precision Machining Technology, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong ' Partner State Key Laboratory of Ultra-precision Machining Technology, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong

Abstract: Much effort have been devoted to the ductile regime machining of silicon carbide (SiC) in recent years. However, a thorough understanding on the mechanism of chip formation has not been achieved. In this study, large scale molecular dynamics simulations are performed to investigate the ductile-regime machining of 6H SiC. It is found that the mechanism of chip formation transforms from shearing to extrusion when the tool rake angle varies from 0° to −40°. The nature of plastic deformation is slipping processes on the basal slip system of 6H SiC and shearing along several inclined planes. Under a rake angle of −40°, a 'pseudo edge' is observed in front of the cutting edge throughout the cutting process. Under a rake angle of −20', a periodic process of formation and vanishing of 'pseudo edge' is observed. The formation of 'pseudo edge' leads to a decrease in the principle cutting force, and its vanishing is followed by increase of principle cutting force.

Keywords: silicon carbide; SiC; ductile regime machining; molecular dynamics; chip formation; nanomanufacturing; simulation; nanotechnology; shearing; extrusion; tool rake angle; plastic deformation; cutting force.

DOI: 10.1504/IJNM.2015.070524

International Journal of Nanomanufacturing, 2015 Vol.11 No.1/2, pp.64 - 77

Received: 23 Jan 2014
Accepted: 19 Jan 2015
Published online: 09 Jul 2015 *

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