A precision design for computer numerical control machining models of involute-generator revolving cutters

Abstract

The paper presents a two-axis computer numerical control (CNC) machining model that can be used to produce the involute end-milling (IEM) cutter. By defining the constant helical angle as the angle between the cutting edge and revolving axis of the cutter, the shapes of cutting edge curves and flute surfaces of the IEM cutter are systematically designed and manufactured by using a proposed procedure using the method of differential geometry and inverse envelope theory. The flute section and feeding speed of grinding wheel are calculated according to the maximal section radius of the cutter. Under the condition of a given angular speed, the speeds of grinding wheel along the radial and axial directions are derived respectively. The use of two supplementary curve cutting edges to resolve the problems of over-cutting and non-existence of the cutting edge at the upper part of end-mill cutters is also considered, together with the smooth conjunction of this supplementary curve with the original helical cutting edge on the shank. According to the results of simulation on the actual obtained flute, the remedial grinding for eliminating the remaining revolving surface is also presented. This paper provides valuable reference for the design and CNC machining of this kind of involute end-milling cutter.