Approach and Development of a Methodology for Machining of Shapes in Cylindrical Bores by Precision Honing

Abstract

In mechanical series production, honing is predominantly used to manufacture high-precision bores according to the current state of technology. This precision machining process usually represents the last machining step in the process chain and fulfills high requirements in terms of shape, dimensional and surface quality within narrow tolerances. Crucial for adherence to high requirements is the coaxial interaction between the honing tool and the workpiece. This paper examines the kinematics of the workpiece fixture in internal long-stroke honing. The focus is on changing the bore shape in contrast to coaxial machining by affecting the workpiece fixture. Controllable honing tools for machining a freeform in cylindrical bores as in combustion engines already exist, but they are mostly suitable for large components due to their size and complex structure. In this context, this paper develops and investigates an approach in the form honing process via the workpiece fixture for bore diameters less than 10mm. For this purpose, the movement dynamics and the degrees of freedom of the workpiece fixture are analyzed and affected by spring components to investigate the impact on the process dynamic and the resulting bore shape. Based on this approach, a gimbal-mounted workpiece fixture is modified with a load cell, leaf springs and equipped with eddy current sensors to monitor the process dynamic at the same time. The investigations focus on the analysis of the potential for machining non-cylindrical bores with an approach, to affect the kinematics of the workpiece fixture by mechanical components to provide a basis for the development of a controllable workpiece fixture. For this purpose, elaborate experiments are carried out and the first results on the bore shape are presented.