Spherical mandrelling method implementation on conventional machine tools

Abstract

The paper presents a new method of finishing holes by means of plastic deformation referred to as spherical mandrelling (SM). The tool motion with respect to the fixed workpiece is a superposition of spherical and translation motion. The surface plastic deformation can be carried out on lathes, drilling and milling machines and machining centres and considerably widens their manufacturing potentials. The mechanics of the SM method has been explained. Two model problems have been formulated and solved and their solutions show the SM kinematics when implemented on conventional machine tools. The solutions to the set variational problems are found by means of an approach called analogy to mass geometry. A simplified diagram of a device and tool for implementing the SM method on conventional machine tools has been shown. The power characteristics of SM process have been determined both theoretically and experimentally and rational operating conditions have been found. A new method of measuring small changes in the load of a.c. motors of machine tools has been presented. SM has been compared to conventional mandrelling and SM efficiency has been proved.