Stereolithography and similar resin-based 3D printing processes are known for building detailed, high-resolution parts in polymer. Now, Incus is leveraging many of the same benefits for metals, with a new process that combines photopolymer resin and metal powder. 

Incus, a spinout from ceramics 3D printing company Lithoz, unveiled its Lithography-based Metal Manufacturing (LMM) process at Formnext 2019. Dr. Gerald Mitteramskogler, CEO, explained the process to me. 

The key to LMM is its feedstock: photopolymer resin filled with metal powder. Unlike most SLA resins that are liquid during the printing process, this material remains solid but spreadable within the 20°C build chamber. “It’s a consistency like butter,” Mitteramskogler says.

A blade spreads the stock over a heated build plate. The photopolymer is cured with a digital light projection (DLP) engine to form each layer. 

The polymerized green parts emerge from the printer in a block of material; an infrared light can be used to liquify the uncured material and quickly free them. 

From there, the process looks more like binder jetting. Green polymerized parts are debound and sintered in a regular metal injection molding (MIM) furnace. The quality of LMM parts is similar to those made via MIM, with the benefits of the geometric freedom and speed enabled by 3D printing. 

Incus currently has four beta printers in the field, printing with 316L stainless steel. Additional materials are in development including titanium, tungsten, copper and precious metals. Lithography-based Metal Manufacturing is possible with any metal that is sinterable, Mitteramskogler says.