Arcam AB fka AMAVF

[Tom Joad]

Reply to pdb2, laser verses electron beam, more like, the characteristics of laser verses electron additive manufacturing and suggestions on what to read. Currently, I do now believe that some parts are best made using EB technology when: full density, metal grain structure, and speed of manufacture are involved, but that can change. Metal grain structure is intricately linked to process so that should identify durable technology moats that aren't as easily changed by innovation. Full density and speed, in my opinion, can more easily be affected by innovation.

If that occurs, that change faces testing and economic viability. I'll leave a couple of links at the end. I'm going to restrict what I'm talking about to full melt processes as they more likely have full density results with the intended stoichiometry. I'm summarizing, below, the qualities of both technologies using generalizations that could be upended by innovation so one might be able to deduce an outcome in the market until that innovation occurs. Whether laser or electron beam manufactured parts are best for an application is difficult to judge and a general knowledge of scientific results helps with applications in aviation, medical, or any engineering application.

Typically, but again I will never say always in the engineering world-

Laser processes: (i) add metal in smaller amounts, (ii) therefore changes in temperature can be huge compared to anything else as the smaller additional melt can cool much faster, (iii) that means that metal grain size can be much smaller, (iv) parts often have to be stress relieved using heat after the build due to tight, small, grain structure from fast cooling (small grain correlates with hardness and brittleness), (v) less total energy in laser 3d but possibly higher concentration of energy, so (vi) build speed is slower than with electron beam.

Electron beam process: (i) natural extension of EB welding, (ii) done in a vacuum so stoichiometry is preserved when using reactive metals, (iii) more total energy so there's more melt in a given time period so faster assembly, (iv) ability to achieve fully dense parts and (v) metal grain in processes described up to this point in time appear to be optimal for applications used, so far, in turbine blades.

Both processes achieve near net shape parts for designs more complex than what's possible with casting. So laser can produce finer detail but I've read, or heard from the Honeywell presentation (unfortunately maybe no longer available on www) that someone in southeast Asia has mysterious mastery with EB and produces shockingly smooth results. So, operator skill has impact on results with EB. Not known whether that's the case with laser. Both appear to give tighter control over alloy proportions than casting but EB has proven itself at this point to an even higher degree with production of a high entropy alloy in significant amount.

Both can produce fully dense parts, that's a holy grail in this business. Voids are cause for concern when stress is involved as failure in a part most likely begins at a void. Voids or general porosity are a problem if absorption of some undesirable medium occurs, or could be desirable if absorption of some medium is desired, so we have to ask if partial density is possible with EB. EB is done in a vacuum because any gas interferes with electrons but I don't know why laser can't be done in a vacuum. Vacuums mean you get a much purer build with no unexpected stoichiometry. Arcam preheats build chambers then controls cooling for metal grain control. I don't know if other electron people do the same with preheating, or if that's possible with their method (was that a Norwegian EB firm with wire feed I saw?). Laser people do a heat treat after the build to control the same, so far.

Some ways to watch for meaningful results:

ORNL and Lawrence Berkeley are doing research with Arcam and any number of laser people but another EB welding firm in I think Norway is doing additive manufacturing with wire feed. I haven't spotted research coming from their machines, yet. (What happened to Google Scholar search!)

Used to steal this one (DN) from me pappy and read under the sheets past bedtime along with Science News. Great general coverage of engineering, and materials science has always been a strong point. Their technical writing puts Motley and any other financially oriented publication to shame so here's one place where you can sort those statements. As we say in statistics, garbage in, garbage out. Don't use bad data.

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Science News, now renamed SN kinda like Kentucky Fried Chicken got renamed KFC. It seems the science and cholesterol scares occurred in tandem so they use alphabet soup to remove the association of science, and fried = heart attack, respectively. Anyway, Science News has always had a mix of brief, accurate descriptions of scientific results along with an exposition or two while Scientific American was dominated by long, informative expositions. I recommend both but will leave the SN link for now. Engineers use science and math and wouldn't make nearly as much progress without. The process and thinking in science shed light on the complexities of EBM and LBM. I'm just hoping to help others bring EB technology into focus and develop an appreciation for the work involved so you're less likely to run for cover at the next Nasdaq/Motley headline.

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Now, I am not an engineer, nor a materials scientist, but a mathematician with a thesis on twinning, a materials science topic. I'm here because I found it difficult to find news on Arcam. So, I'm happy to find others that have the background to appreciate what's going on with EB technology.