Most manufacturing customers have heard of electric discharge machining—more commonly known as EDM. But did you know that there’s more than one kind of EDM? 

Wire EDM and sinker EDM are part of the EDM family, meaning they’re non-traditional machining methods that use thermal energy to remove material from a workpiece. At Heinz Engineering, we leverage both capabilities to provide our customers with the highest quality parts.

Understanding Wire EDM and Sinker EDM Services

We always select the capability that best suits the part we’re manufacturing. But many of our customers find it helpful to understand the differences between processes like wire EDM and sinker EDM. 

Wire EDMWire EDM

Wire EDM uses a continuous feed of electrically charged wire to remove material via electric discharge. The wire is constantly replenished—much like a sewing machine with thread—meaning we’re always cutting with a fresh tool, and each cut is as precise as the last.

The wires used in wire EDM are typically made of brass (or other conductive materials) and can be as small as 0.002” in diameter, enabling us to achieve tight tolerances and cut corners as sharp as 0.005-0.007”. Wire EDM services are ideal for through holes, through cavities, and through contours. 

Sinker EDM

Instead of working with a continuous wire, sinker EDM leverages a machined electrode made of carbon or graphite. The electrode is dropped into the part to create blind cavities or features that would be challenging or impossible to cut with a traditional mill or lathe. 

The electrode is shaped to fit the feature it’s cutting and can burn down over time. There are, however, techniques we can employ to prolong the use of an electrode. 

For instance, we may program cutter compensation, which allows us to maximize the reach of an electrode as it’s burning out and create a slightly larger pocket than we could otherwise. Since this method involves shaking the electrode as it burns, it’s best for making rough cuts, followed by finishing cuts made using a second electrode.

Your Part Could Benefit from Wire EDM or Sinker EDM Services

EDM is a great option when conventional precision machining isn’t feasible or is cost-prohibitive due to custom tooling requirements and labor-intensive operations. In many cases, using EDM saves our customers substantial time and money while ensuring they receive high-quality parts that meet all specifications.

Both wire and sinker EDM are comparable in price and precision. It’s possible for our customers to need one or both of these capabilities. If you aren’t sure which one is best for your part, tell us to machine the part per blueprint, and we will determine which capability will yield the best outcome. Request a quote today!