Elasto-hydrodynamic interaction in the free abrasive wafer slicing using awiresaw: Modeling and finite element analysis

Citation
M. Bhagavat et al., Elasto-hydrodynamic interaction in the free abrasive wafer slicing using awiresaw: Modeling and finite element analysis, J TRIBOL, 122(2), 2000, pp. 394-404
Citations number
26
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Mechanical Engineering
Journal title
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
ISSN journal
0742-4787 → ACNP
Volume
122
Issue
2
Year of publication
2000
Pages
394 - 404
Database
ISI
SICI code
0742-4787(200004)122:2<394:EIITFA>2.0.ZU;2-F
Abstract
Free abrasive machining (FAM) process associated with the wiresaw wafer sli cing involves a three body abrasion environment. During the process, the cu tting action is caused by fine abrasives freely dispersed irt the slurry, w hich get trapped between an axially moving taut wire and the ingot being sl iced, bt this paper a model is proposed wherein the entry of abrasives into the cutting zone is governed by elasto-hydrodynamic (EHD) interaction betw een the slurry and the wile. An EHD film is formed by the abrasive carrying viscous slurry, squeezed between the wire and the ingot. This phenomenon i s analyzed here using the finite element method. The analysis of such an in teraction involves coupling of the basic Reynold's equation of hydrodynamic s with the elasticity equation of wire. Newton-Raphson algorithm is used to formulate mid solve this basic coupling. The finite element discretization of the resulting nonlinear equation is carried out using Galerkin's method of weighted residuals. Basic hydrodynamic interaction model and the incorp oration of the entry level impact pressure into the inlet boundary conditio ns are the two novel features introduced in this work. The analysis yields film thickness profile and pressure distribution as a function of wire spee d slurry viscosity, and slicing conditions. A perusal of results suggests t hat the wiresawing occurs under "floating" machining condition. The minimum film thickness is greater than the average abrasive size. This is practica lly very important since the wiresaw is used to slice fragile semiconductor wafers with severe requirements on the surface finish. The possible mechan ism by which a floating abrasive cart cause material removal is also touche d upon in this work. Material removal rate has been modeled based on energy considerations. [S0742-4787(00)00702-5].