Ultra-precision grinding of a hydrostatic mechanical sealing ring face with extremely shallow taper angle

Abstract

This paper investigates the potential application of infeed grinding using a rotary table and cup grinding wheel to process a sealing ring with extremely shallow tapered faces. A mathematical model for the shape of the face of the ring is developed. The shape characteristics and the influence of machine parameters, such as the distance between the centres of the rotary table and the grinding wheel, the wheel's radius, the pitch angle, and the roll angle on the conical error, are investigated. An optimization model is developed that defines the minimum form error and the optimal machine configuration parameters. It is found that the face of the ring can be approximated as a circular conical surface. It is shown that the minimum theoretical form error is less than a nanometre for rings with an outer diameter of 300 mm. It is predicted that infeed grinding using a rotary table and cup grinding wheel is capable of processing the face of the ring to high form accuracy and this prediction is validated by experimental results.