Basic study of superfinishing of hardened steels
Abstract
A force sensing system has been adapted and used to measure the forces acting on the abrasive stone during superfinishing of hardened steels. By combining measurements of forces and material removal rates, specific energy and force ratio have been characterized. A systematic parametric study of material removal rate, force ratio, specific energy, and surface finish is detailed. A sharp transition regime characterized by an abrupt change in these quantities occurs at a stone oscillation frequency of about 1600 cpm. This characteristic frequency is independent of the contact pressure ranging between 0.4 and 0.9 MPa. The data is used to construct a superfinishing process map to give valuable guidelines for selecting a good combination of operation parameters to improve process efficiency and control workpiece surface quality. Additional experiments are performed to characterize evolution of surface roughness and material removal rate. The transient data is combined with dimensional analysis to develop an empirical model that links process parameters with surface finish and material removal rate. The resulting surface roughness model provides the capability to design an optimal process in terms of minimum process time and cost. In conjunction with the experimental parts of this work, a simple physical model rooted in contact mechanics, moving heat source theory, and cutting edge height statistics of stone surface is developed to estimate forces and local temperature rises at abrasive-workpiece contacts. Finally, the contact mechanics model predicts component surface roughness produced by the superfinishing process.
Degree
Ph.D.
Advisors
Farris, Purdue University.
Subject Area
Aerospace materials|Mechanical engineering|Industrial engineering|Materials science
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