Study of the contact force in free-form-surfaces compliant EDM polishing by robot

With an elastic negative pole being driven by ultrasonic vibration and being moved along the surface of the workpiece compliantly by robot, a new kind of effective EDM, compliant EDM, cuts the electrically conductive materials away and polishes workpieces of free-form surface. The study of the contact force between the end of the polishing tool and the surface of the workpiece is the key for the study of the cutting mechanism of compliant EDM and to make better use of it. This paper makes a model for the contact force and verifies it by experiment and simulation based on the theory of elastic body kinetics and dynamic stress concentration. The research work shows that this contact force is caused by both the electrical impulsion of EDM and the mechanical force of ultrasonic vibration, the discharge frequency of compliant EDM having a much more closer connection with the vibration frequency of the polishing tool than with the frequency of ultrasonic vibration.