Metal Additive Manufacturing – Standing on the Shoulders of Giants

2021-02-10

Lee-Bath Nelson  

Xerox-3D-printing 3-2

There are many metal additive manufacturing (AM) technologies and yet additional technologies are still being added. Of the several new emerging technologies in the recent year, a couple caught my attention because they focus on using readily available (non AM specific) materials. Using pre-existing materials or machines is smart because it is more cost effective and more flexible in uncertain supply chain times: you can source the material and later on decide if you use it for manufacturing technology A or B. Similarly, a new material that can turn a plastic 3D printer into a metal 3D printer is also expanding the use of existing resources – again, cost efficient while enhancing flexibility. Using the same machine for multiple uses can be more sustainable too. The devil is in the details, so here come some details.

Tritone 3D printed parts

Molding Powder

At FormNext 2019, diagonally across from LEO Lane‘s booth was the Tritone booth – an Israeli start up that came out of stealth mode at that event. Tritone’s metal technology is called MoldJet and the name is a hint to how it works: each layer goes through 4 steps in 4 different stations in the machine (which can all operate simultaneously for different items) in a round robin fashion: 1. the machine 3D prints a mold of the next layer in plastic (filling the negative space of the part with plastic). Layer height is 40-200 micron and can vary from layer to layer, even in the same part.  2. the molded layer is filled with metal slurry which is a mixture of powder (more on that below) and water based binder. 3. The layer is dried and hardened using heat and a suction of moisture. 4. The layer is inspected for defects (the layer can be removed if a defect is detected). After the entire green part is 3D printed, the entire green part in its tray goes to a low temperature oven that removes the mold – because of the drying and hardening process, Tritone claims there is only 2% binder in the green part which means a high density of metal. The green part then goes to a high temperature sintering furnace which is the final (6th) step. It seems a complicated process – why go to all this trouble? I think one important feature is that this process enables using MIM (Metal Injection Molding) powder to create the slurry. This is a standard material – the MIM market is estimated to be almost $3Bn in 2020 – and therefore lowers the material costs for this technology. Tritone claims this technology works for most MIM powders. Tritone also claims that, in spite of the large footprint of the machine, the 6 stations are an advantage as they can all operate in parallel. Hopefully, the time required in each station is also compatible so that in-process trays can move synchronously from station to station. Because there are 6 stations working in parallel, the throughput can reach 1.6liter/hour.

A year later (and what a year!) in November 2020, Tritone announced it has installed its first Tritone Dominant beta system at Runout, an Israeli service provider.

illustration of Xerox liquid metal 3d printing technology from AM Power

Dripping Liquid

Another recent reveal is Xerox’s Liquid Metal 3D printer called ElemX which is based on technology Xerox acquired 2 years ago from Vader Systems. ElemX uses standard aluminum wire stock as its raw material. This means the raw material is more affordable than specialty AM materials. Xerox also claims that it gives final material properties that are the same or better as in traditional manufacturing technologies with the same raw material. The technology (illustrated above by AM Power) seems to be the metal parallel of Arburg’s Plastic Freeforming technology (except the latter starts with standard pellets). The metal wire enters a heated small reservoir where it is melted. Then, an electromagnetic field (controlled by AI software) turns the liquid metal into drops. The size and frequency of the drops can be modulated via the electromagnetic field. The molten drops solidify instantly as they hit the substrate or part below. In a recent presentation Tali Rosman, the General Manager of 3D Printing and VP at Xerox, explained that the use of standard aluminum wire has many advantages: it is a cheaper material, and it is harmless (can be easily stored and handled and doesn’t require any special ventilation etc). She also claims that this technology enables higher throughput through faster 3D printing. The importance of safety and ubiquity of material is especially clear for those looking for a metal technology that can be deployed in distributed micro factories such as in malls and small workshops.

Just this month Xerox announced it is collaborating in a research project with the US Naval Postgraduate School on Metal AM research and has placed its first machine there.

Deposit Filament

About the same time Tritone did its reveal, at FormNext 2019, BASF‘s Forward-AM unveiled its Ultrafuse 316L stainless steel filament. This filament also stems from MIM (Metal Injection Molding) powder only in this case it is turned into a filament and used on a standard FDM (or FFF) 3D printer such as the Ultimaker. The resulting green part needs to be exposed to a furnace in 2 temperatures but after that the result is a stainless steel item that was printed on a desktop, highly affordable 3D printer. This is a boon both for small service providers in a distributed model, and a way to expand the uses of the existing install base of desktop FDM 3D printers. The catch is, of course, the need for the furnace but ForwardAM has established a network of furnace service providers to address this.

All the technologies and materials presented here have the potential to expand the reach of metal additive manufacturing into more affordable and wide spread uses. It remains to be seen how much adoption these innovations will inspire – this will determine the longer term impact of the technologies. At least in 2 of the 3 examples we are talking about very large companies (Xerox and BASF) so moving the needle for these organizations is a tall order. But even if it doesn’t move that needle it could move the needle for the AM industry, we’ll have to wait and see.

For more insights and information on additive manufacturing (3D printing) follow us on LinkedIn or subscribe to our newsletter for weekly updates. Pictures: top photo Xerox 3D printed metal part, Tritone 3D printed part, and illustration of Xerox technology by AM-Power.

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