Lobing Behavior in Centerless Grinding—Part I: Stability Estimation

Abstract

This two-part paper addresses the lobing behavior associated with centerless grinding. Part I establishes a system model (the lobing loop) for lobing analysis and develops methodologies for lobing stability analysis, and Part II investigates lobing characteristics and proposes remedies for lobing suppression. The lobing loop shows that lobing behavior is of kinematic nature, caused by the interaction between the geometric rounding mechanism and regenerative cutting mechanism. A bidiagram-matical method is subsequently developed for lobing stability estimation. It was found that lobing is inherently unstable, and the characteristic roots of the lobing loop are limited within their respective root neighborhoods in the u-plane. This leads to: (1) a method of lobing stability estimation using the growth rate boundaries, and (2) an efficient way of solving for the characteristic roots using a Taylor’s series approximation. The availability of growth rate boundaries and characteristic root distribution provides an effective tool for the control of lobing in centerless grinding.