The AddUp group, a global metal additive manufacturing OEM, has released a recipe for shaping AISI 420 steel. This material, commonly used in the field of plastic injection molding, can now be used for additive manufacturing. AISI 420 steel will enable tooling manufacturers to develop new, more complex, and more efficient molds, and is now available for all FormUp 350 New Generation Powder Bed Fusion (PBF) machines.
AddUp, a joint venture between Michelin and Fives, is one of the first companies in the metal 3D printing sector to offer a recipe for implementing AISI 420 steel. Also referred to in the German standard as 1.4021, or 1.2083, this stainless steel is commonly used to manufacture molds for plastic injection molding, as it has both high mechanical strength and good corrosion resistance. This development for AISI 420 adds to an already broad portfolio of materials AddUp offers for the tooling sector – including 316L stainless steel and Maraging 300 (M300) steel.
“Unlike alloys specially designed for additive manufacturing, which require users to invest in developing suitable post-processing, we offer here a widely used grade,” said Frédéric Sar, Materials Manager at AddUp. “With AISI 420, the post-printing operations are identical to those of parts produced by forging. Existing solutions in heat treatments, surface treatments, machining settings, and insert grades are directly applicable to printed parts.”
As a result of this development, manufacturers have a wide range of treatments at their disposal – enabling them to target specific properties for each application. For example, the ‘quenching/tempering’ type heat treatments that are already available for raw 420 steel allow printed parts to display tensile strength characteristics in the range of 1350 to 1980 MPa, with elongation at break values of 2-10%, depending on the tempering temperature. Standard surface treatments, such as nitriding, can also significantly increase the surface hardness of parts after machining. Finally, the AISI 420 alloy does not contain cobalt or nickel – making it compatible with the requirements of the REACH directive.
AddUp has recently installed a FormUp 350 New Generation PBF machine at the WBA (Aachener Werkzeubau Akademie GmbH), Germany’s leading technical center for tooling. The machine is equipped with AISI 420 stainless steel powder and the newly developed recipe – making it capable of printing parts with meager porosity rates (less than 0.05%, which guarantees durability for molds subjected to high stress). With this new industrial production tool, German tool manufacturers can submit their application cases and will be supported at all stages of their projects, from assistance in designing optimized molds to printing parts and studying the feasibility of mass production. Significant gains are expected, both in terms of productivity and part quality, as demonstrated by a project already completed with AISI 420 for the Siebenwurst Group.