Patent ID: 7692114
Filing Date: 2010-04-06
Classification: B23H

Abstract:
1. A method for forming a tapping in a bore comprising the steps: (a) inserting an electrode bearing threads into a bore; (b) rotating the electrode orbitally without revolving about its own axis at a distinct predetermined depth of the bore around the circumference of the bore while machining corresponding threads on a wall of the bore by electroerosion to initiate the formation of an unfinished tapping in the bore during a first longitudinal pass through the bore wherein the electrode operates at a first set of machining parameters; (c) providing a control unit for repeating step (b) a preselected number of times to complete a corresponding number of longitudinal passes through the bore, the machining parameters being varied with each pass until a finished threaded tapping is created; and (d) each orbital rotation of the electrode around the circumference of the bore occurring without axial displacement through the bore.