A Numerical Contour Method for Simulating Spiral Groove Bottom Profiles

The envelope method can be used to model the spiral groove surface profile in single screw compressors produced by cylindrical milling using the contact lines of the cutter surface and the groove. However, the envelope method cannot predict the groove bottom profile accurately because it does not account for the boundary contact lines on the end face of the cutter. A new numerical contour method is proposed to model the groove bottom profile by identifying the contact points on the end face of the cutter to a set position on the spiral groove. Results show that the new method can calculate accurately both the boundary and the inner contact line and thus simulate the groove bottom profile exactly. This method could also be used to simulate other profiles of machines, such as rotor profiles of twin screw compressors and screw pumps.