Don’t underestimate post-processing. Because it’s still relatively unknown in broad market circles, many companies tend to look at metal 3D printing, and metal AM in particular, as a black box. Experts say it’s a misconception to assume most offerings are a plug-and-play machine and that there won’t be significant machining and finishing work required to ensure a part comes out finished as intended.
Companies diving into metal AM need to cultivate an understanding about how particular materials operate in terms of structural integrity as well as gain a clear picture of what’s required for surface finishing and heat treatment to ensure there is no deformation and that parts will meet required tolerances. Often, companies don’t factor in the need for machine shop capabilities as an integral part of the metal AM process.
Those firms that go into metal AM with a strategy that starts with design and goes all the way through inspection and testing have better results with implementation, Houle says.
“Those that have a plan from the ground up for implementing metal 3D printing have a strong track record of ROI,” he says. “Those that bring in the technology and try to find different parts or applications they can convert do not.”
Matsuura’s LUMEX Avance-25 and Avance-60 metal laser sintering system focus on a hybrid approach, which streamlines post-processing work, Houle contends. The systems combine a powder bed metal AM platform with subtractive machining capabilities to ensure quality parts are finished with maximum precision.
SPEE3D’s supersonic 3D powder deposition (SP3D) process also helps defray post-processing challenges while operating up to 100 to 1,000 times faster than traditional MJF 3D printing processes, according to Bruce Colter, vice president and general manager for the Americas region of the company.
SPEE3D is based on cold spray technology, typically used for parts repair and coating, which combines high-pressure carrier gas with metal powders and operates below the melting point of the metal in use so it achieves a high density of deposits and low residual stresses. The resulting process requires far less heat treatment or post-processing work to get a quality finished result.
“The dirty little secret of metal AM is that often 60% of the process time is spent at the back end, de-stressing, heat treating or HIP (Hot Isostatic Pressing) parts as part of the finish work,” Colter says. HIP refers to a process that exposes components to simultaneous application of heat and high pressure to help form the part by compacting the metal powder and eliminating porosity.