A metal AM expert dishes on powder and system improvements

Franziska Maschowski, business development manager for TRUMPF TruPrint products.

Metal 3D printing crosses markets. And those in machining, fabrication, and other areas of conventional manufacturing have been paying attention.

A high-end, previously machined part could be totally redesigned to take advantage of all that additive manufacturing (AM) has to offer, complete with impossible-to-drill internal contours and impossible-to-mill contours. In this sense, metal additive complements machining.

On the other hand, metal 3D printing fuses metal particles together; it is essentially welding and, therefore, potentially in the wheelhouse of a high-end specialty fabricator. If a specialty fabricator—like those serving industries such as aerospace, medical, and defense—is eyeing metal AM, it should start with the basics: what these technologies are, what they can and can’t do, and what’s hype and what’s not.

I recently interviewed a member of TRUMPF Inc.’s additive manufacturing team—Franziska Maschowski, business development manager for TruPrint products. I asked her what’s needed to build good parts and how advancements in lasers have improved metal 3D printing.

“You need three factors to produce a good part,” Maschowski said. “You need a good machine, you need good process parameters, and you need good powders.”

Modern powders are specifically designed for metal AM. They exhibit properties like “feasibility” traits (analogous to weldability) that make them perfectly suited for a certain process or additive application. This includes materials with low levels of carbon—different from, say, tool steel alloys used for decades in the mold and die industry. A material chemistry that’s very machinable may not be feasible for a metal additive process.

Laser advancements have also pushed metal AM forward, Maschowski said. “We now have smaller focal diameters that result in better surface roughness and finer details, and you can build parts with higher dimensional accuracy.” Despite improvements in 3D printing capabilities, the process is not the best way to produce big parts. The reasons are the relatively high cost of powder and the lengthy build cycle.

But what about printing a number of small parts on a 3D printer with a large bed? This, Maschowski said, probably wouldn’t be a good approach either. Using a single laser to print a large bed of tiny parts still would take a long time and require a lot of powder. And if the parts were being built with a certified manufacturing process, there may be limits to how that powder can be reused.

A multilaser system would be plausible, but instead of powering one giant system, Maschowski suggested running several smaller, right-sized machines that could produce small parts on demand.

Dental devices built on a multilaser AM system.