Some Aspects of the Hard Machining of Bore Holes

The machining of hardened surfaces can be done even fulfilling the ever stricter accuracy and quality prescriptions, besides the economic efficiency. Decisively, hard machining is highlightedly important in finish processes because the components must meet increased functional demands. Therefore the number and/or the hardness of the hard surfaces on the components is continuously increasing. In practice the demand for such components is high since they are more wear resistant and their tool life may be higher. Today there are several possibilities for finish machining of components having hard surfaces. We have done experiments for hard machining of inner cylindrical surfaces. The examined procedures were as follows: grinding, hard turning, combined machining. The first two procedures (hard turning, grinding) have got different procedure-specific advantages and disadvantages. Combining these two procedures, using-up the advantages of them, the efficiency of the production can be increased. This paper outlines these procedures of hard machining, their applicability, the increase of their efficiency, and the possibilities provided by the combination of the procedures.