EDM and Additive Manufacturing Similarities

Parallels exist between electrical discharge machining (EDM) and additive manufacturing processes for industrial part production.

CNC EDM equipment arrived on the scene in the late 1970s. Soon after, it was ballyhooed by some as being the nonconventional machining technology that would sound the death knell for  traditional chip-making processes for part production. EDM (in its wire, sinker and hole-drilling versions) has since settled into a comfortable niche for machining very hard, electrically conductive materials. Common applications include machining mold cavities, micromachining and creating diffuser holes for turbine blades.

Conventional milling and turning remains.

Similarly, some pronouncements about burgeoning additive technology—largely from mainstream media outlets—suggest that it will result in the eventual demise of subtractive machining operations. You know what? That won’t be the case, either.

Conventional milling and turning will remain.

EDM technology is more mature compared to additive, at least in terms of additive being applied for production. The speed and capabilities of EDM have advanced with developments such as digital generators, linear motors, “turn-and-burn” operations, reduced wire and fine-hole drilling diameters, and even probing capability. However, to the extent that it excels in certain applications, it remains a technology that complements conventional machining.

Additive still faces hurdles in the form of accuracy, surface finish, slow build time, limited work envelope and so on. In fact, secondary conventional subtractive machining operations are sometimes required for additive parts to allay issues such as these. That said, these challenges will continue to be addressed by additive equipment manufacturers, material developers and even end users in the coming years.

To be sure, additive, like EDM, will have an impact on part production, largely because it can create forms and features that are difficult or impossible to produce via conventional machining. In fact, it will change the way designers think about alternate forms and features they can now integrate into their new products.

Still, conventional machining isn’t going away. Instead, additive will settle into its own niche as yet another complementary technology to subtractive machining. This is summed up nicely in Peter Zelinski’s March 2017 article about Imperial Machine & Tool’s use of selective laser melting (SLM) technology, in which he writes: “Imperial has now integrated additive into a shop-wide process in which additive is no longer something special, but instead has a seat at the table that is equal to all of the other contributors to a given job’s success.”