Thread turn milling simulation

Abstract

The study shows that the high-performance thread turn-milling process with a synchronous rotation of the helical milling cutter and the workpiece is not widely adopted since there are no reliable methods to estimate the organic thread formation errors. The thread is machined as an envelope curve along the elementary surfaces of each cut shifted along the workpiece axis by a fraction of the thread pitch inversely proportional to the number of the cutter teeth. Domestic and international researchers tried to analytically estimate the thread formation errors at the part face. Such an approach failed to produce acceptable results since thread turn-milling is a three-dimensional process. We analyzed the thread formation errors in 3D using COMPAS 3D CAD system and developed a simulation model. We modelled a reference 3D thread machined on the workpiece; a 3D resulting thread; a single cutter tooth path in the plane perpendicular to the workpiece axis; 3D cut by a single cutter tooth. We also simulated the entire process and made a 3D model of the machining errors by subtracting the reference part geometry from the 3D thread model, and estimated the errors. The results were checked for consistency (max deviations) and acceptability for each dimension. The undercut dimensions were obtained by subtracting the 3D part model from the 3D reference model. Conversely, the overcut dimensions were obtained by subtracting the 3D reference model from the 3D part model.