Drive Control of Dithering Table for Grinding

Abstract:

In grinding viscous materials, such as stainless steel, aluminum and many polymeric materials, the application of a dither on the workpieces proves to be an effective way to enhance the quality of surface finish. A linear stepper motor is utilized for this purpose. By means of the PWM control to the adjacent phase coils, the linear stepper can drive the sliding table to make reciprocating motion and also to produce a desired dither signal, while the grinding is undertaken to the attached workpiece. In this paper, a linear stepper motor is introduced to drive the sliding table and a modulated control strategy is used to control the linear stepper continuously, which also generates an additional dither on the sliding table and the attached workpiece. The dither amplitude can be adjusted by means of the modulated frequency. Experiments are designed to measure the practical dither signals and to verify the effectiveness of improving surface finish quality using a dither. It is demonstrated by both theoretical and experimental results that by means of proposed table drive, a rather wide band of dither signal can be acquired and can meet the most demand of viscous material grinding.