When you’re in the business of making the impossible possible, you’re always finding new and exciting ways to get things done. Sometimes, that means investing in the latest and greatest technologies. Other times, it means discovering innovative uses for existing technologies that have been around for decades.
An “old school” technology we’re using to push the boundaries of what’s possible at our precision machine shop is wire EDM.
Wire EDM (electrical discharge machining) is a thermal machining process that uses an electrically charged thin brass wire as an electrode to cut materials that are capable of conducting electricity.
While conventional CNC precision machining processes use cutting tools to remove material from a workpiece, wire EDM is a non-contact manufacturing method, meaning the wire never touches the material. Instead, the current between the wire and the material creates a plasma that vaporizes the material, leaving behind the desired shape.
Dating back to the 1970s, wire EDM has been the gold standard for tool and die applications due to its ability to cut precise features in hardened tool steel. The tolerances that must be held between the punch and the die are generally too tight to be held if they are machined prior to heat treat. At the same time, conventional machining after heat treat is difficult because cutting tools don’t hold up well on hardened materials, and heat from cutting can impact the hardness of the material. EDM allows all critical features including dowel holes and cutting profiles to be machined accurately after the block has been heat treated.
Needless to say, wire EDM was a game-changer for tool and die applications and is the standard process for those components today! In fact, Wagner Machine initially began offering wire EDM in the 1990s so that we could do quick-turn repair work for these components. However, in our ongoing quest to make the most complex machined parts, we realized that wire EDM could do so much more.
Why exactly is wire EDM such an essential capability for a precision machine shop to offer? Here are a few reasons:
Wire EDM is capable of cutting most materials—the only caveat is that the material must conduct electricity. But in terms of the material’s hardness or softness? Wire EDM doesn’t discriminate.
We can cut anything from .005” thick brass shims to 16” thick tool steel that has been heat treated to 62 Rockwell C.
Because the wire never touches the part, no physical pressure is applied during the cutting process. That means we can cut delicate or small workpieces without the risk of damaging them. We often use conventional machining to make most features on a part and then use the EDM to cut small features or slots that would make the part too weak for conventional machining.
Conventional Design for Manufacturing (DFM) wisdom informs engineers that the ideal length to diameter ratio for a feature is 3:1 to accommodate standard end mills. At Wagner Machine, we can machine features with ratios up to 10:1 in many instances, but there is still a limit to conventional machining.
Wire EDM changes the game quite significantly, allowing us to cut through materials up to 16” thick with a 0.0075” corner radius. That’s a ratio of over 2100:1!
Parts like gears may require a huge upfront investment of $10,000 or more in custom tooling just to make one specific profile accurately. With wire EDM, there are no special tools to buy—just a program change. Because wire EDM is a CNC process, we can cut any 2D shape you need with minimal setup costs and tolerances down to .0001”.
At Wagner Machine, we’re used to working with skeptical customers who are unsure if their complex designs are possible to manufacture. In many cases, they aren’t aware that wire EDM is an option or how this capability can bring their complex designs to life.
So we’re here to remind you: don’t compromise on your designs. We’ll find a way to make almost anything happen, whether we use wire EDM or one of our many other in-house capabilities.
We recently invested in a new (to us) Makino DUO64 and are ready to put this machine to work on your next part. Request a quote to work with us!