Texture prediction of milled surfaces using texture superposition method

It is difficult to evaluate surface error in three- or multi-axis milling due to the complexity of the machining geometry. This paper presents texture superposition method to evaluate the surface asperity of milled surfaces. In order to derive overall surface generation mechanism of three different types of endmill cutters including a ball endmill, a filleted (torus-shaped) endmill, and a flat endmill, a generalized cutter model is proposed by introducing the fillet radius as a variable. The surface roughness is determined by the maximum height of the effective scallop including the effects of cutter marks and conventional scallops. The runout effect caused by the geometric inaccuracy of a cutter is added to make the predicted surface closer to the actual machined surface. Through these steps, three-dimensional surface topography, according to given cutting conditions and cutter types, can be formed. From machining experiments with a three-axis machining center, validity of the developed method was verified. The method proposed in this paper can be used to improve the efficiency of three- or multi-axis milling and to generate optimal cutter paths and cutting conditions.