Material removal energy in ultraprecision machining of micro-lens arrays on single crystal silicon by slow tool servo

Abstract

An accurate evaluation of the energy consumption in machining provides useful instruction for energy saving. In this paper, the material removal energy in ultraprecision machining of micro-lens arrays on single crystal silicon by slow tool servo was investigated. Theoretical models were firstly proposed to illustrate the evolution of the material removal energy, material removal rate (MRR), specific cutting energy (SCE) and stresses. Experiments were then conducted with different cutting parameters, and surface morphologies as well as cutting forces were also analyzed. Results show that the total material removal energy decreases with the increasing of feedrate, but the maximum material removal energy increases by about 90.67% and 6.25% when the feedrate increases from 1 μm/rev to 2 μm/rev and from 2 μm/rev to 3 μm/rev, respectively. The SCE at the feedrate of 3 μm/rev is much smaller than that of 1 μm/rev and 2 μm/rev, which is induced by the formation of cleavage fracture. Furthermore, the required removal energy to overcome deformation in the right region of the lens is higher than that of in the left region even at the same MRR. The formation mechanism of the cleavage fracture and its effects on the cutting were also discussed with respect to crystalline orientations and surface energy.