The direct metal laser sintering (DMLS) process continues to evolve to meet medical device needs. The technology can be used in mission critical parts, but requires some tradeoffs. Smooth surfaces have been difficult to achieve, and handling the nano-sized metal powders required is difficult and potentially dangerous. Suppliers are attempting to resolve those flaws in the system to make DMLS a go-to manufacturing process for small and micro-sized parts often needed in medical devices.
Höganäs, a company based in Sweden, offers Digital Metal technology. It builds parts using precision ink jet on a powder bed, with a MIM-type oven to achieve finished parts that are high resolution with smooth surfaces in a minimal amount of time at competitive pricing. One of the keys to achieving those characteristics is that the part is not affixed to a build plate. It has no support structure or strode, so there is no need to remove those portions post-build. In addition, the print happens at room temperature, so there is no melt during build. The process does require sintering. Complex geometries are possible with Höganäs’ process, so fine parts such as gears, levers, and buttons are possible. The Höganäs process yields 99.5% density, in comparison to general DMLS processes, which range form 95% to 97% density. Components are currently predominantly made from stainless steel. However, the company says materials such as titanium, silver and copper are close to commercialization.
XJet has released a NanoParticle Jetting technology to create thin walls and smooth surface finish. NanoParticle Jetting is a distinctive process that uses nanoparticles in liquid suspension to build 3D metal parts. Delivered as sealed cartridges, these materials, as well as the support materials, can be loaded by hand into the XJet system, eliminating the need to handle metal powders. XJet’s system print heads deposit an ultra-fine layer of liquid droplets, which contain stochastic metal-nanoparticles onto the system build-tray. The required support is generated automatically by the system. Inside the system’s build envelope, extremely high temperatures cause the liquid ‘jacket’ around the metal nanoparticles to evaporate. This results in strong binding of the metal with virtually the same metallurgy as traditionally-made metal parts. In addition, the metal part needs to undergo an easy sintering process, with the supports removed simply and with almost no manual intervention.
XJet is an Israeli firm that recently completed a round of funding of $25 million, led by Catalyst CEL Fund, a private Israeli-Chinese private equity fund and Autodesk Inc. through its Spark Investment Fund.