LOBING BEHAVIOR IN CENTERLESS-GRINDING .1. STABILITY ESTIMATION

This two-part paper addresses the lobing behavior associated with cent erless grinding. Part I establishes a system model (the lobing loop) f or lobing analysis and develops methodologies for lobing stability ana lysis, and Part II investigates lobing characteristics and proposes re medies for lobing suppression. The lobing loop shows that lobing behav ior is of kinematic nature, caused by the interaction between the geom etric rounding mechanism. and regenerative cutting mechanism. A bidiag rammatical method is subsequently developed for lobing stability estim ation. It was found that lobing is inherently unstable, and the charac teristic roots of the lobing loop are limited within their respective root neighborhoods in the u-plane. This leads to: (1) a method of lobi ng stability estimation using the growth rate boundaries, and (2) an e fficient way of solving for the characteristic roots using a Taylor's series approximation. The availability of growth rate boundaries and c haracteristic root distribution provides an effective tool for the con trol of lobing in centerless grinding.