I'm as skeptical of XJet's treat to Arcam as I am to Arcam's treat to XJet. I'm sure both processes have their advantages. First, I want to get some poor Motley writing out of the way.
XJet is not using liquid metal. They are using nanoparticles of metal suspended in a liquid medium. Motley is not known for their tech-writing.
All of these companies we're talking about have developed some AM form of powder metallurgy. One advantage of powder metallurgy is the ability to control, on a small scale, the proportions of metals in the final product. I assume that consistent mixing on a small scale implies consistent mixing on a large scale. It was an Arcam printer that was used to produce substantial amounts of high entropy metal recently, proving their printer's capability in controlling proportions. High entropy alloy is a mix of 5 or more elements in equal proportion, mole-wise, not volume or mass-wise. That is a monumental development that proves the extent to which proportions can be controlled and no other type printer has been successfully used to obtain that result, yet. I suspect there will be some time that passes between HEA production and economic viability, but that level of control is remarkable.
XJet's technology promises "fully solid" parts. Fully solid is not the same as fully dense. For example, Aerogel is a solid that's not nearly fully dense. Rigorous testing is required to prove that you're obtaining fully dense material in your process. In the XJet process, the part is formed with the jetting medium, then the part is sintered, so layers of powder are not fully melted as in the Arcam process. Unless they have some major, mind-bending development, which I doubt, there's no way to develop a fully dense part by packing spheres unless shrinkage is acceptable after eliminating voids. I doubt they're using a particle geometry that self-packs into a fully dense part because they talk about driving off the liquid medium within the part with heat. If the particles self-pack into a fully dense part, no heat is required to drive off the liquid medium. Moreover, whatever this liquid is, I doubt it's water, there will be residue in the final product. For medical implants that could be a problem.
Arcam products produce parts with superb fine grain structure. Research has shown the grain structure can be manipulated in the direction of part construction. XJet's process requires heating the entire part in post production. I believe Arcam has a moat here as with Arcam's equipment, grain structure is controlled on a small scale as the part is built and the grain structure they are getting is superb.
Their [XJet's] jetting technology depends on a suspension of metal nanoparticles in what appears to be a proprietary liquid medium. A nanoparticle is between 1 and 100 nanometers in diameter. For scale, the smallest pollen particle comes from the Forget-Me-Not at 0.006 micrometers. That's 60,000 times larger in diameter than the largest nanoparticle. The physics of nanoparticles are different than the physics of larger particles and smaller particles. I wouldn't doubt that Brownian motion and surface charges affect their jetting medium at this scale even at deposition sites. Let's say, I'll be very interested in their ability to control proportions.
Please look at my past posts for citations/links. I've not posted much so it shouldn't be too difficult.
AI
