When micromachining, a wire EDM offers distinct advantages. It can cut complex contours, meet tolerances of ±0.0001" and impart surface finishes of 0.18µm R_a and finer. Also, in a properly executed operation, the wire never touches the workpiece, eliminating cutting forces and enhancing accuracy.

Effectively controlling the spark energy of an EDM’s power supply is critical to meeting cycle-time and part-accuracy requirements for all sinker EDM applications. But it’s especially important when micro-sinker-EDMing because a lack of control causes more electrode wear, and—in the fine-feature micro world—when you lose a little, you lose a lot.

MicroEDMing has made major strides in recent years, both in terms of the equipment used to perform it and the quality of parts shops are able to make using the process. MICROmanufacturing asked several experts for their thoughts on the most important improvements made in microEDMing over the past 5 years. They identified several, from machine design to electrode materials to wire-threading capability.

Electrical discharge machines have been used commercially for more than 30 years, with the tool and die industry being the first to adopt the technology. Since then, other manufacturing sectors have steadily added EDMing to their parts-producing capabilities.

Small-hole EDMing is performed with a spinning electrode. Shown is a 0.040"-dia. hole being EDMed in a 0.5000"-dia. ball bearing.