Down to the Wire: Think Wire EDM is Only for Tool and Die? Think again.

Aug 31, 2021
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Cut thin to win. That’s what my uncle used to say. He was talking about the card game Cribbage, not wire EDM, yet the adage holds true either way. That’s because Wire EDM (WEDM) uses ultra-thin wire from 0.1 to 0.3 mm (0.004″ to 0.012″) in diameter to slice through any electrically-conductive material up to a foot or more thick. It does so with great accuracy. In fact, WEDM easily holds accuracies of 0.001″ or better. And contrary to what many might think, it’s just as suitable for aerospace and medical job shops as it is tool and die.

Wonderful Wire EDM

How does Wire EDM work? As with conventional EDM, it uses high-voltage electrical current to erode material. But where sinkers use a shaped electrode made of graphite or copper, WEDM uses a spool of continuously-fed wire. The most common type is made of brass, an alloy of copper and zinc alloys, although there’s also tungsten, molybdenum, and steel-core wire available. Whatever it’s made of, this wire is guided through the workpiece like an extremely high-end bandsaw.

Wire EDM offers many advantages. For starters, hardness doesn’t matter. As long as the material is electrically conductive, WEDM can machine it. This means polycrystalline diamond, tungsten carbide, hardened steel alloys, tool steel, aluminum, and more. As already mentioned, WEDM is also very accurate, as in tolerances of ‘tenths. Lastly, it can produce practically any part shape—if you can draw it on an Etch-a Sketch, you can probably cut it on a WEDM.

Compared to milling and turning, Wire EDM isn’t very fast. Depending on the thickness and material, a workpiece might take hours or sometimes days to complete. However, clever shops will often stack multiple pieces of thin-gage material one atop the other, then cut dozens, perhaps hundreds of parts in one operation. This is a very efficient approach to machining parts like shims and metal gaskets.

Turn out the lights

Best of all, wire EDM runs completely unattended. If the wire breaks, an auto-threader loads more wire and keeps on going. That’s why many shops will build a fixture that can hold huge numbers of smaller parts, then use WEDM to cut oddly-shaped holes and other features that would otherwise be impossible to produce. Such machining is both high-quality and hassle-free.

They can also cut tapers. For example, Kent USA’s line of wire EDM machines have up to 3.93″ of U and V-axis travel. This means tapers of ± 22.5° are possible, depending on the part thickness. There’s also the choice between flushing and submerged models, different tank sizes, and a range of axis travels. All of them boast AC servo motors and a user-friendly control, and are backed by Kent USA’s 15-month warranty. Interested in wire EDM? Looks like you have some decisions to make.

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