The Kneeslider

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Metallic Glass – Injection Mold Metal Like Plastic

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Metallic glass rod - metallic glass part as it comes from the mold - final part after excess is trimmed
Metallic glass rod - metallic glass part as it comes from the mold - final part after excess is trimmed

Metallic glass popped up in the comments following our article about rapid prototyping and I thought I’d look into it since it was new to me and sounded like something quite a few of you would like to know about, too.  Things are advancing so fast now, it’s hard to keep up, but this is another technology worth understanding because it might have some pretty interesting uses in manufacturing.

Here’s the quick rundown:

  • Stronger than steel or titanium
  • 20 times harder than plastic but can be injection molded like plastic
  • Quickly heat the metallic glass with an electrical pulse to its liquid state (550 degrees C)
  • Mold and cool before it can crystallize like metal

The heating to the liquid state is done really fast (at a rate of a million degrees per second) using a process called ohmic heating, utilizing a short but intense electrical pulse (1000 joules in one millisecond)  which brings the metallic glass up to temperature in half a millisecond. A few milliseconds later it is injection molded and cooled before it can crystallize, retaining the hardness of glass with the toughness of metal. You get the economics of plastic manufacturing applied to metal parts. The new process is called “rapid discharge forming.”

The speed of heating and cooling is the key, if it takes too long, the metallic glass forms a crystalline structure before the process is complete.

Since this is a new process, it’s unclear what limitations there might be, but as with rapid prototyping, once engineers and designers see how this can be applied, they may be able to focus design decisions on their ideal form instead of on economics or manufacturing feasibility.

Technology is changing directions so fast you have to wear a seatbelt just to read about it. I love it!

Link: Caltech via Next Big Future

Comments

  2. Advance the metallic glass a little farther so we could make a see through motorcycle engine! Just imagine the the light from combustion at night!

  3. I love the idea of a see-through engine! The light show would be amazing.

    All kidding aside, this is amazing technology. The biggest stumbling block in all engine design is the limits of the materials. If an engine could be made from materials able to withstand far higher temperatures and stresses than current materials like aluminum and cast iron, efficiencies would take a giant leap. Imagine a metallic glass 500cc engine, turbocharged to make 100 hp at 20,000 rpm and weighing about 30 pounds, installed in a bike with featherweight frame and components, also made from metallic glass. The entire machine might weigh 200 pounds. And if the engine could be made transparent, or at least translucent, that would be a bonus.

    • For B50 and cycledave, metallic glass isn’t transparent like window glass, it’s still metal but with the disordered atomic structure of glass, which means they are resistant to deformation, a property of glass but also not brittle, a property of metal.

    • I thought that a polymer engineer in San Francisco started working on the matrix in 1986. I’ll see if I can get a progress update.

      • The article linked to above indicates metallic glasses were discovered at Caltech in 1960.

        … or am I missing a Star Trek reference?

        • Okay, so I’m guilty of starting it in the other thread but I can’t hear “transparent metal” without thinking of Trek IV. Glad I’m not the only nerd around here. Thanks again Paul for posting all of the fascinating “future of manufacturing” articles. This is really good stuff. I think very exciting things are going to happen to motorcycles in the next decade. As an aside, to all of the younger crowd reading here that know nothing about the movie we’re talking about. If you are still deciding what to do about a career, seriously give some thought about going to trade school for high-end manufacturing. If you’re good with math, there is a desperate need in the United States for skilled CNC machinists, Tool and Die makers, and a whole host of trades related. Most of folks who do this now will be headed towards retirement soon. Better than working as a coffee barista trying to pay off that philosphy degree. Who knows? You could end making some very cool motorcycle parts, live long and prosper!

        • To Moto Random.
          I’m seeing the need for skilled machinists and prototypers too… That’s why I inted to go back to Uni to become an engineer. And not to become a dork behind a screen, but work on the machines.
          I’ve spent 10 years behind a computer, now I want want to get my hands dirty – it’s a primal thing – and finish the day having made something.

          We were told time over and again when we were teens that manufacturing was “basic” thing and that being a manager or shifting imaginary money was the future. I don’t want to be part of that make believe future anymore.

          Bring on the tools!

        • @ MotoRandom & Gildas,

          There is still a ton of prototyping going on in the US, particularly anything that needs to be precise, high end, custom made, or all of the above. From my own experience running CNC equipment, there is a wealth of knowledge to be developed and it is very much a dark art in so many ways. A lot of the finer points of how to machine anything, or make anything for that matter, are highly proprietary. It takes pretty creative and clever people to reverse engineer a process or to come up with their own.

        • I have to agree with Gildas, It’s immensly satisfying to design something in your head, and then go make it, Even better when it works as intended!

  5. QrazyQat —
    You’ll have to talk to Scottie about that transparent aluminum.

  6. Wow, I love the idea of a see through engine! I’d be very interested to see how this metallic glass holds up to impacts tho. But heck, in the meantime, I’d happily take a super awesome see through glass knife!

  7. I always thought that in “Star Trek IV” they were talking about transparent alumina, a real but expensive ceramic related to sapphire with properties much like they described.

    This metallic glass may find a number of uses where one would want something like aluminum, but tougher. However, the rapid cooling time requirement limits the size and intricacy of the mold one could use. Injection molding is most economical for parts that must be made in large numbers, so on motorcycles I would expect metallic glass to show up first in bearings, brackets, and custom fasteners.

    Metallic glass could be adapted to 3D printers, though the power requirements for sintering it from powder could be high. More exciting is the possibility of using this ohmic heating approach to build 3D parts through macro-scale sputtering, resulting in essentially zero waste material.

    Captcha word = Ampere. How appropriate.

  8. Hmmm. Transparent metal? I don’t think so. Stronger than steel? Relatively and only under certain circumstances. Metallic glasses appear to be very springy but prone to sudden and catastrophic failure in tension. For the properties of metallic glasses have a look here http://en.wikipedia.org/wiki/Amorphous_metal

  9. The name is back to front and confusing it’s not glass it’s metal. Wouldn’t glassified metal would be more accurate?

  10. This reminds me of liquid metal. Another casted metal but does not form a crystal structure. The crystal structure is what causes weaknesses.

  11. I imagine an engine block may be too large to cool quickly enough, but smaller parts like wrist pins, brackets, and any sort of fitting would benefit from this development. I wonder how well transmission gears would fare…

  12. As Mike above points out, it would actually be considered “Glassy Metal” Though metallic glass does roll off the tongue more easily. Though the proper name (As he also links to with wikipedia) would be Amorphous Metal. I’m not trying to be picky, just want you to know you’ll get more info by searching for that second term. Read about it in Discover magazine some years ago, back when they could only make very thin sheets of it. This does seem a major leap forward for the manufacturing process. As an example, I believe the original article I saw quoted the researchers as saying that they had made some sample products, such as a razor blade. It supposedly stayed sharp for months of daily shaving.

  14. Wasn’t one of the Terminators made of fluid metal?
    Now if he’s (it) gonna be out there it’s scary!!
    Seriously though.. my father was an engineer (finished his working life working on top secret projects for the British government) and he would have loved this stuff!!

  15. In reality, I do know this metallic glass is not transparent. yet it opens up a new world to rapid prototyping One can dream right?

  16. So I sent this article to my dad yesterday, and as it turns out, he’s worked with this material! I can’t say what it was for or who it was for (it’s a trade secret), but my dad says the material is “amazing to machine”.

    I think my dad has forgotten more about metals than I will ever know…

  19. Interesting it may be but without more information it remains just that. For example how does the holohayaline nature effect it’s density. Crystal structure has effect on the actual material density so I assume that lack thereof will also effect it. metal atoms would have a substantial replusive effect on one another, so glassifing it would have an effect on the packing. Glass ( silicon dioxide variety) has a tetrahedral base structure which allows closest packing and attraction so ends up as strong and dense. Metals?…
    Still the ability to zone harden using glass surfaces zoning to a more malleable core/base could give the best of both worlds …wear tolerance AND toughness.
    laser machining would be possible I would think , or ultrapressure liquid jet.
    Cylinder liners or pistons ( crowns?) seem an interesting direction and cams ( faces zone process?).