A compensation method for enhancing the accuracy of milled rotors based on cutter modification and corrected cutter position

Abstract

Form milling is a suitable method for manufacturing the screw rotor of a vacuum pump due to its advantages, including time efficiency and low cost. However, the manufactured rotor profile (RF) often fails to meet the design specifications due to machine tool errors, such as vibration and temperature fluctuations. To address this, the present study proposes a mathematical model to enhance the machining accuracy of the milled screw rotor by applying a corrected cutter position or cutter profile modification. First, a generalized coordinate system is established to design the side cutter profile based on the theoretical RF. A six-axis computer numerical control (CNC) machine is then used to simulate the cutting process of the screw rotor and evaluate the variance in the RF’s normal deviation under the corrected cutter position and cutter profile modification scenarios. A closed-loop method is proposed to derive the corrected cutter position or profile. Numerical results demonstrate that profile errors are significantly reduced by approximately 49.19% in the corrected cutter position case, successfully achieving the target tolerance for the corrected cutter.