CUTTER CORRECTION METHOD FOR IMPROVING THE ACCURACY OF MANUFACTURED SCREW ROTOR BY END MILLING CUTTER

Abstract

The accuracy of the rotor profile is a significant factor in the vacuum pump performance. However, the manufactured rotor profile deviates from this theoretical form because of cumulative machine-tool errors—such as temperature changes, humidity, and nearby vibrations. Therefore, a cutter-correction method is proposed to improve the accuracy of the manufactured profile by compensating for profile errors during cutter design. A mathematical model of the design end-milling cutter profile, accounting for compensated cutter parameters, is first proposed. The influence of the compensated cutter parameters on the rotor profile error is analyzed and summarized in a sensitivity matrix. The correction cutter profile is established using the compensated cutter parameters, which are solved by applying the sensitivity matrix and Levenberg-Marquardt algorithm. The numerical example is used to verify the effectiveness of the proposed method for reducing rotor profile error.