An Uncut Chip Thickness and Surface Finish Model for Contour Turning with a Corner and Edge Radiused Insert

Abstract

Uncut chip thickness h and total surface finish profile height Rt is modeled in general contour turning where feed rate is oblique to the workpiece X-axis in the XY plane. The insert surface was parameterized with arc-lengths along corner and edge radius applying a common template. For true insert orientation, projecting the grazing curve GC on the XY plane, h was measured normal to projection at every point. Revolving the GC about X, its subsegment producing surface finish imprint solved and Rt calculated. Contact extremities agreed with published data in cylindrical hard-turning. Brammertz BE and Side-Flow SF effects in surface generated were further modeled. The Rt plateau at low feed rates for BE was smaller for smaller minimum uncut chip thickness (hmin) imposed. A greater side-flow angle (SFA) increased Rt for a fixed feed rate. Tighter bounds to published Rt varying hmin and SFA were rapidly obtained due to use of the common template. Departure from plane strain responsible for SF at cut extremity on the finished surface based on published orthogonal cutting width to h ratios were quantitatively predicted.