3D Printing High-Strength Aluminum | Hacker News Reader

3D Printing High-Strength Aluminum

futurism.com

73 pointsjonbaer31 comments

So like all the other "3d printed" metals this appears to be laser-sintered.

This is the big bait and switches of the 3d printing world: You take a consumer process (heating up ABS and mushing it together) and conflate it with an industrial process (laser-sintering) so that the public thinks that 3d printed aluminum will soon be available in their maker bot.

The story here is that some researches have developed some aluminum alloys with good mechanical properties that can be laser-sintered.

This means they can be used in an industrial additive manufacturing process that has as much in common with your 3d printer as a drop forge has with a panini press.

3D printing is pretty much just 3 or 4 vaguely related approaches that happen to aim for the same end goal.

Sort of like 2d printing (laser, ink jet, dot matrix, thermal transfer, plotter).

There are a few SLS printers that are approaching home/SB use pricing, <$10k. I don't think CO2 lasers are that expensive to build so I would imagine pricing can drop a fair bit if the volume gets there.

Sintering metals requires far more powerful lasers than the the cheaper SLS models have, the cheapest models capable of sintering aluminum are much closer to the million dollar mark. The ultra-cheap-market-disrupting-startup Desktop Metal is supposedly going to have something for $120k soon which is an enormous leap over what's currently available but I doubt it'll hit hobbyist level pricing anytime remotely soon.

Just wait till consumers find out how toxic those fumes and particles really get with laser-sintering- and the whole market evaporates anyway.

Compared to $120k for the printer, getting a fume hood installed in your house would be a pretty negligible cost.

Desktop metal isn't sintering it's powered metal deposition in a resin matrix.

The parts then need to be baked in an oven at near melting point temperatures.

Which is super exciting really! Formlabs, who make a really nice stereo lithography printer, announced an SLS printer[1] recently for $10k and I think they will do pretty well with it. They only list nylon as a material right now, but this sort of iteration is exactly what it takes for us to get affordable high quality additive manufacturing machines.

[1]: https://formlabs.com/3d-printers/fuse-1/

Lots of this would be fixed if "rapid prototyping" caught on as the phrase rather than 3d printing.

3d printing (or more broadly rapid prototyping) is unfortunately seen as "the way" to make things for consumers despite the parts you get out frequently severely lacking in some way (form, fit, function). "3d printing" in the most common everyday usage is printing plastic. If you say 3d printing people will click. If you say Selective Laser Sintering or SLS, very few people would click.

I wish people would take a bigger interest in manufacturing and making stuff for themselves (within reason). If the part you're printing is a constant thickness with a simple profile and a rod coming out of a hole, go buy a dowel and stock material. You'll get your part faster and you won't be paying 2.50+ per cubic inch of material AND it won't delaminate.

But that isn't as easy as clicking a button and getting your replacement part that is far out of spec from your crappy sub-1000 dollar 3d printer.

Most people in the industry talk about Additive Manufacturing instead of 3d Printing for industrial metals AM.

It's like that Ninja Turtles branded mutagenic ooze that was supposed to turn me into a mutant ninja, but it was actually just cornstarch, water, and food coloring.

You need a similar level of naivete to think a warm plastic extruding machine can print metal.

I don't see why it can't, at least with low melting point metals like tin and lead.

Aluminium is tougher, you need 660°C, but why do you think that's impossible to achieve on a regular 3D printer with some modifications?

It's not the temperature that is the problem (at least not until you get into copper or steel).

The problem is that molten metal is a liquid. When you melt a filament, the metal will flow away into the thing you are printing, and then keep flowing until it cools down. Extrusion printers can only work with viscous fluids that must be pushed out of the printing head and will stay in place once deposed at the working piece.

Here are people printing in tin and bismuth:

https://www.youtube.com/watch?v=aSzz7jWRlkQ

Indeed, that is interesting. In retrospect, yes, solder has some good potential for printing material.

I thought “3D printing” referred to any additive process like this. I never understood it to imply a consumer-level process costing single-digit thousands.

Isn't it just enthusiasm for additive processes in general?

I don't see what agenda misleading the public about expensive industrial machinery would serve.

Is carbon weaving or automatic fiber placement (AFP) considered additive manufacturing?

Carbon weaving loom robot can produce complex high strength objects from carbon fiber. It's clearly not carbon fiber 3d printing.

https://www.youtube.com/watch?v=uWhoV02AuTU&list=PL8C19F0048...

Whatever the commonalities of the processes of the various process, I don't see why a process of creating an industrial 3D press that can create "real" solid objects wouldn't eventually allow a transfer of that tech to consumer-grade printers.

Altogether, it seems like when an industrial 3D printer can fully print itself, the path to making printer consumer grade would be a lot clearer.

What they mean by "high-strength aluminum" is "not worse than regular solid aluminum". Some 3D printing processes produce a material much weaker than the raw material. Filament-type printers are notorious for this.

Here's laser deposition welding.[1] Works fine. Slow. Has to be done in an inert atmosphere.

[1] https://www.youtube.com/watch?v=d2foaRi4nxM

I wonder if anyone is exploring metallic foams as an orthogonal technology.

This foamed-metal watch case was recently in the news [1] (though it's less exotic than the escapement inside it).

1: https://www.hodinkee.com/articles/zenith-defy-lab-oscillator...

Metal lattices have been a pretty common 3d printing thing for a while, but its obviously cheaper to make them traditionally. Most metals print more easily than aluminum- aluminum is highly dependent on precipitation hardening/aging, to the point that it never would have been used in airplanes otherwise.

6000 and 7000 series aluminimiums are used a lot in road bicycles so that would seem like a natural application outside of heavy industrial/automative applications.

I wonder if there are novel shapes of bicycles that could be enabled by this; a triangle made out of tubes has a good strength-to-weight ratio, but perhaps it could be improved?

I doubt you could do anything to a bike frame with this that you couldn't with foam-core carbon fiber. The advantage 3d printing over CFRP is cost is constant with intricacy and number of joints. That means its best for skeletonizing to a small scale or lightening really intricate parts, and expensive for large, sweeping parts (like the shape of a frame).

So, you could skeletonize things like brake levers/mechanisms to a much higher degree than with older aluminum alloys. The ultimate limit to skeletonizing something is the tensile strength since each member basically becomes a wire eventually. At that point its strength is determined by the tension it can sustain rather than the bending force.

Very interesting but they didnt actually say how they made the non-weldable metal, weldable. Would be interested to know what it is they actually did.

This article has more detail.

https://www.seeker.com/tech/materials/nanoparticles-keep-3d-...

"They used a computer program to sort through and analyze more than 4,500 different alloy and nanoparticle combinations to see which ones had atomic structures that would fit together best. The idea was that the grains of metal would glom onto the tiny nanoparticles, sort of like a water vapor droplet that nucleates around a particle of dust to create a drop of rain. They found that a nanoparticle made of hydrogen-stabilized zirconium would work best with two different kinds of aluminum alloys."

u/fibbonachi11235 had a really fantastic couple of comments on the materials science[1] when this hit r/3dprinting.

[1]: https://www.reddit.com/r/3Dprinting/comments/71cnq6/high_str...

Usually when key information (like price, but also sometimes key tech) is left out, it's because they want you to contact them so they can begin the formal sales process.

In this case, though, since there is a Nature [1] article about their technique, the details just didn't make it into the Futurism article.

[1]: http://www.nature.com/nature/journal/v549/n7672/full/nature2...

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