Machining 3D-printed metal

Are you being asked to quote secondary machining operations on a handful of 3D-printed metal parts? If so, how do you cut these parts?

A quick Google search returns images of some cool-looking components, but what’s with all the curvy geometries and gnarly surface finishes that, at first glance, appear rougher than corn cobs? 3D-printed parts must be tough to machine, right?

Actually, there’s little to worry about, at least from a machinability perspective.

According to industry experts—such as the additive-manufacturing consulting firm Wohlers Associates, Fort Collins, Colo., and simulation and product development experts Phoenix Analysis and Design Technologies (PADT)—3D-printed metal from laser-based powder-bed fusion systems cuts no differently than a billet of 17-4 PH stainless steel, titanium, Inconel or one of the many other alloys available today.

This titanium hip implant looks like tough stuff, but the most-difficult thing about machining parts like these is fixturing them. Image courtesy of McClay Tooling.

“In general, for parts printed using powder-bed laser melting processes, we recommend the standard speeds, feed rates and cutting tools found in the Machinery’s Handbook,” said Rey Chu, principal of PADT, Tempe, Ariz.