Most people would consider metal 3D printing is only suited to high performance applications often with a costly investment in capital and operational resources, writes Paul Quinn, lead additive manufacturing applications and training engineer, Inspire3D.

Ultimakers launch of the Metal Expansion Kit enables desktop Metal Fused Filament Fabrication (MFFF) machines such as the Ultimaker S-line to produce 17-4PH stainless steel parts with other metals to come in 2023. MFFF targets a different sweet spot of components that may be costly to produce but typically required in very low volumes. These components may include:

  • Bespoke, one-off components
  • Small functional prototypes
  • Custom tools and fixtures
  • Small series production
  • Plastics replacement parts exposed to high loads or temperatures

The process is a little different in comparison to other metal 3D printing processes and is outlined in the three stages below:

  1. 3D Printing to produce a green part
  2. De-binding to remove the polymer carrier in the filament and,
  3. Sintering to produce a dense metallic part.

After these stages have been completed your left with a 17-4PH stainless steel part with above 96% density that can be CNC machined, sand blast and treated like a traditional stainless-steel part. The excellent mechanical properties on a level with CNC machined components, tolerances achievable to within ± 0.4 mm after de-binding and sintering as well as the high corrosion resistance open the applications space for MFFF Printing.  

MFFF, however, can play a role as a complementary technology to CNC when it comes to small volumes of complex, customised parts that have features more suitable to be built additively. This is true for complex features that would require a high amount of preparation effort on a multi-axis CNC machine. And especially true when order volumes and material waste are considered. 

The new metal expansion kit enables low volume production of custom applications in-house on an Ulitmaker 3D printer, saving anywhere between three to 10 times on traditional milling machines or powder bed metal 3D printing for a low initial investment cost. This makes the metal expansion kit a competitive solution comparted to other metal manufacturing methods achieving a very fast return on investment often in the region of two years for many adopters.

Users can now explore a new range of metal 3D printing applications by upgrading Ultimaker S-line printers with the Metal Expansion Kit. This brings a simpler workflow to make creating stainless-steel parts easier, more efficient, and more affordable. Here is everything you need to successfully produce metal parts on the Ultimaker Platform:

  • Ultimaker S-line printer (S3 or S5) with an air manager
  • Ultimaker Metal Expansion Kit, which includes filament, print cores and accessories
  • Ultimaker Cura 5.1 or higher
  • The latest print profiles downloadable from the Ultimaker Marketplace

For more information on how to get 3D printing with metal please get in touch with Inspire3D by visiting our website,,  or emailing

Author: Paul Quinn, lead additive manufacturing applications and training engineer, Inspire3D