There was a time, 20 or 25 years ago, when electrical discharge machining (EDM) was a mysterious and misunderstood process mastered by but a few shops. For these shops, EDM was their "secret weapon." It could do things that other metalworking processes couldn't do. Working with EDM required patience and persistence. It could be tricky and unpredictable. In those days, EDM was often characterized as "non-traditional" or "exotic," but that characterization wasn't entirely inaccurate.
Yet the ability to erode the highly detailed shape of a formed electrode into a hardened piece of metal or slice an intricate path barely wider than the diameter of a fine electrode wire opened up all kinds of new manufacturing possibilities.
Then, year after year, the equipment became more reliable, more capable and easier to use. It became more affordable. Breakthroughs in solid-state electronics made the process much more controllable and predictable. Cutting speeds and metal removal rates went up. Computer numerical control made a high degree of automation possible. Advances in CAD/CAM improved programming. EDM was gradually joining the mainstream of metalworking processes.
But in the last few years, EDM seemed to lose ground to other processes in certain quarters. Advances in milling, turning, grinding, laser cutting and abrasive waterjet began encroaching on EDM's territory. Hard milling, for example, has been displacing EDM as an effective way to machine certain mold and die cavities. At a recent machine tool show, exhibitors were demonstrating how five-axis milling with extremely small end mills could produce corners as sharp as those once only attainable with a ground EDM electrode. "Eliminates EDM" has become a selling point for a variety of processes.
As some shops make a strategic retreat form EDM, others should be re-examining what the latest in EDM technology can do. The process continues to become faster, more efficient, cleaner and more automated. EDM has always rewarded those who approached it with imagination and creativity. Fortunately, that hasn't changed. The kind of manufacturing that seems to have the brightest future in this country might loosely be described as "nontraditional" and "exotic"—the work that is too daring, too demanding or too vital for off-shoring.
This could be exactly the situation that calls for "secret weapons" in the hands of imaginative and creative manufacturing companies. I'll bet that EDM will be part of that arsenal.