Analytic mechanistic cutting force model for thread milling operations

摘要

In this paper, the mechanistic cutting forces for thread milling of the ISO metric screw thread are predicted. The force model is composed of surface and edge force components. The cutting edge is modelled from the geometry of the milling cutter, including the helix angle and thread tooth profile. To determine the specific cutting force coefficients for surface and edge force components, the cutting forces are measured with a dynamometer along a horizontal linear path and compared with the calculated force by means of the exact uncut chip thickness which results from the modelling of chip volume per tooth at a prescribed time on the thread milling cutter. The run-out errors are considered to estimate the uneven cutting force distribution for each tooth. The measured cutting forces for the brass workpiece material (CuZn37) for a linear path shows quite good agreement with the simulated cutting forces. The results indicate that the proposed cutting force model for thread milling can be used in order to adapt cutting parameters, such as feed per tooth and axial depth of cut for the purpose of increasing productivity in practical application.