Simultaneous prediction of surface topography and surface location error in milling

Abstract

The machined surface topography, surface roughness and surface location error are very important evaluation indexes for machining quality, which directly affect the performance characteristics of the machined workpiece. In this paper, a new model of the arbitrary point of the cutter edge with respect to the arbitrary frame of the machining feature point is built. The proposed model incorporates the surface location error into the relative motion of the cutter with respect to the workpiece using the harmonic balance methods. Further, a nonlinear programming problem is proposed to obtain the scallop value of an arbitrary point on the nominal machined surface. Since the obtained scallop value of each point can be used for constructing the topography of the machined surface as well as calculating the surface roughness, the proposed model can simultaneously predict the surface topography, surface roughness and surface location error. Simulations and experiments indicate that feed per tooth, runout and number of cutter teeth are vital factors influencing the topology of the machined surface. The surface location error of the cutter due to the number of cutter teeth is an essential factor that influences the parallelism or perpendicularity of the machining feature. The effectiveness and feasibility of the proposed method is verified by a machining example.