Analysis of the Process Dynamics for the Precision Honing of Bores

Abstract

The finishing of precise bores is an important machining step, especially in the automotive industries. Bores can vary in diameter and form, from bigger piston bores in motor cylinders to rather small bores in fuel injection systems. Quality parameters for these bores are form- and geometric accuracy as well as surface roughness and structure. All requirements can economically be met by using the honing process as the final finishing operation for readymade bores. Honing is an abrasive machining process using abrasive grains usually made of diamond or Cubic Boron Nitride (CBN) in metallic bonding. During the process three movement components, namely an axial movement along the bore axis, a rotational movement around the bore axis and the feeding movement of the honing stone, are combined. The feeding movement of the honing stone is induced by an axial movement of the feeding cone, which is translated into a radial movement of the honing stone at the interface between honing stone and work piece. The feeding movement is decisive for the results of the honing process. For a regulation of the process that enables high process stability and repeatability as well as good quality results from the first part it is important to know about the forces in the feeding system of the tool. The following paper describes the static and dynamic correlation of the process forces in order to give a basis for a new regulation approach especially for bores with smaller diameters (below 20 mm) where the direct measurement of the process forces with a tool- integrated sensor is difficult. Measured signals are investigated for their dynamic influences. The theoretical approach is then compared to signals measured during the process.