Production EDM, for the most part, still uses standard toolroom EDM machines which include elaborate fixturing and/or bulky workpieces. For example, large C-framed machines capable of lifting several hundred pounds, are still being used withelectrodes or electrode assemblies weighing only a few ounces. The result is an expensive, over-dimensioned machine tool capable of handling heavy electrodes and not necessarily able to respond correctly to small electrodes. In addition, there is alarge waste of energy in running the relatively large, hydraulic servo system.

Another approach taken by EDM manufacturers is to build a custom EDM machine which is capable of performing only one job. Such a machine is not only costly, but delivery times are typically very long. Also, when the particular job for which themachine has been designed is completed, the machine is worth very little to the user. In any case, the original purchase can only be justified in economic terms if the machine is to be used for a relatively long run of jobs.

Consequently, there is a need for a flexible, yet accurate, modular EDM system which can be easily assembled to perform a given job and then can be taken apart and rearranged for the next job. This is to be contrasted with a standard, toolroomEDM machine which includes many features which are never used during production jobs. By buying a modular system, one need only buy components necessary for a particular production job.

Such a system should also be adaptable to accommodate such devices as rotating spindles having rod or wire electrode refeed, electrode holders, either single or multiple; slotting heads with automatic wear compensation; and automatic toolchangers.