Computational model for the steady-state elasto-hydrodynamic interaction in wafer slicing process using wiresaw

摘要

A computational model for analysing the steady state elasto hydrodynamic (EHD) interaction in the wiresaw slicing process is presented in this paper. In this model, the coupling of the steady state motion of the translating wire and the hydrodynamic behaviour of the abrasive carrying slurry is studied. A numerical scheme incorporating the finite element method (FEM) and Inexact Newton-GMRES method is employed to solve the governing equations. By applying this method, better computational efficiency can be achieved than by using the typical Newton-Raphson method. Therefore, extensive parametric studies are made possible. Results from the parametric studies indicate that the noncontact floating machining mechanism dominates the wafer slicing process using the wiresaw. Direct contact machining, however, also may occur when the contact span between the wire and the ingot is short, coupled with the lack of slurry. Simulation results also show that too large a bow angle of the wire may cause the breakdown of proper EHD condition, resulting in the ductile ploughing of abrasive particles on the ingot surface. This computational model can provide insights into the mechanism of the wiresaw slicing process, and suggest process control methods to facilitate industrial wafer slicing process using slurry wiresaws.