Three-dimensionally controlled EDM using cylindrical electrode (4th report) - Basic research on contour machining.

In the three-dimensionally controlled electro-discharge machining (EDM), it is important to develop machining programs which compensate the electrode wear in machining processes. In these programs, it is generally considered effective to divide a whole machining process into some characteristic steps and to adapt a suitable compensating method in each step.On the basis of above consideration, some experiments are performed about one of the methods which is a combination of a rough machining step with large blocks in higher depth of cut (for brevity, “large block machining”) and a fine contour machining step with remaining small blocks (for brevity, “small block machining”). And suitable compensating methods of these steps are investigated. From the results, the following conclusions are mainly obtained.1) In the large block machining, it is effective to compensate the cutting length of electrode at the time when this electrode length has worn out.2) In the small block machining, it is necessary to compensate both the wear of electrode length and of electrode radius.3) It is possible to obtain a practical machined surface by using the above compensating method and by giving lower depth of cut.