Sinterhard, a US start up based in Massachusetts, is developing metal powder filled filaments for use in existing 3D filament printers.

The company says that Sinterhard Metal Filled Filaments will enable people to print items that are furnace ready to debind and sinter into solid sintered metal objects and could be a viable alternative to metal injection molding (MIM).

The ABS and PLA plastic filaments can be mixed with either powdered 316 stainless steel or aluminium. The plastic can be removed from the printed part via a debinding, using a solvent or by thermal evaporation. The remaining low density metal part can then be heated in a furnace to the sintering temperature, which closes the metal pores, to near full density and hardness.  Depending on the sensitivity of the metal to oxygen, the furnace will be a controlled atmosphere furnace or a vacuum furnace.


‘The 3D printer will replace the plastic injection molding machine in the MIM process, and later with oxide and non-oxide ceramic filled filaments in the ceramic injection molding process (CIM),’ said company founder Bill Kovacs on Sinterhard’s Kickstarter page.

‘In selecting 316 stainless steel and aluminum powders, we are starting with two of the most common metals that are in use making parts with the current industrial MIM process. They have a moderate sinter temperature (316 stainless steel) and a low sinter temperature (aluminium) as a starting point. These metals cover a large range in commercial applications and are available in the fine mesh size we need to insure a high quality 3d printed part.’

In existing commercial MIM and CIM processes, a thermoplastic is mixed with a metal or ceramic powder, melted and injected into a mold cavity in the molding machine. The molten thermoplastic resin conveys the metal through the runners and is cooled and the frozen plastic part removed from the mold. However, filament 3D printers can be used instead of the injection molding machine, and the company suggests that Sinterhard Metal Filled Filaments could replace the MIM feedstocks. 

The company plans to develop a low cost, table top debind and sinter furnace project funded by a Kickstarter project. 

‘In launching Sinterhard Metal Filled 3D Printer Filament [...] we are creating a direct path for 3D printing to help grow the existing US$1.6 billion MIM and CIM market for complex, small industrial parts,’ Kovacs said.  

The Kickstarter page can be found here.

This story is reprinted from material from Sinterhard, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.