Did people see that press release last week about an open source metal printer that only cost $1500 bucks and would cure all ills and bring world peace and so on?
Well, the original release didn’t show any printed parts and the information on how the thing worked was sparse although it was clear they were using a MIG welder and a delta printer (with the delta inverted and the workpiece attached to the end effector).
I managed to find the academic article that details the work and here is the only thing they had produced at the time of publishing.
What do people think? - the guys who wrote the paper seem to think it’s a viable means of making metal components. I aint’ so sure…
Yeah not exactly finished product
It’s better than I imagined, but they need to work out infill techniques. That little test sprocket would need too much secondary machining to be practical, but a larger, more complex part with limited machining could be good fit for the process.
Did they say how it sticks… And more important, how they get it off the build platform?
@Eclsnowman from what I could tell, they just welded straight onto sheet steel and removed it with an angle grinder I assume. It’s still going to be terribly limited imo, any kind of overhang will pose problems if nothing else.
@Eclsnowman I haven’t seen the paper but I’m willing to bet they use a sacrificial platform of some kind.
Ceramic tile like you’d see in wood stoves. Parts list here: \http://www.appropedia.org/Open-source_metal_3-D_printer
They mentioned that it should get better as more people make them and find ways to improve it.
Do prototypes really have to look professional though? It may be enough to just get a quick basic structure.
I guess the real question will be how does the strength and fracture toughness compare to standard powder metal components or wrought steel components. If the strength is comparable it may be useful for rapid prototyping or “one off” components.
Assuming it will get better as other people improve on your design seems like an awfully poor assumption. There are no clear benefits to this method right now, but abundantly clear pitfalls to it.
You may get a few more copies built by tinkerers with time and money on their hands, but even that seems a little doubtful to me. Maybe I’m just overly cynical about it.
I think if you need shell shapes this could be pretty useful. It’d be more useful if you were using a TIG torch and much finer wire, I suspect. But there’s some intelligence in welding, that’s going to be hard to transfer to a computer. Some interesting discussion on the hackaday post about this, using tacking the wire and then stretching it along from point to point for very serious bridging.
Seems a real issue might be machinability., i’ve tried milling welded materials before and it’ll destroy a cutter. These parts would need to be reheated and normalized to be reworked.
Seems easier to make some plastic patterns for casting or use lost plastic process.
At that level of detail, you would need to make parts much too large for this inverted delta setup to support for it to be at all practical. I’m thinking D-shape scale. Even so, I’ve never seen fasteners large enough to be practical for use with parts with a minimum feature size this big.
I’m inclined to agree with the pessimists, I’ve done a lot of mig welding in the past and I think you’d end up with a lot of melted tips and so on while developing this idea, not to mention the surface quality and machining limitations. TIG seems like a better option as it gives you more control and could handle a smaller feedstock. The rhetoric in the paper is waaay too optimist imo, they make like this is the way to do cheap metal printing. Personally, I think we are going to see the price of high wattage lasers plummet over the next few years and that combined with the expiration of the SLS patents will spark a surge of open sintering designs. After all, Cartesian or Galvo driven laser solutions are well understood and people are making good progress with powder deposition methods.
how small is the smallest MIG I wonder? google isn’t very helpful based upon my cursory searching.
BTW, you could get better detail metal printing using laser/plasma/waterjet cutting (or even cutting with a blade like in a vinyl cutter with thin enough foil) and spot welding or some type of high-temperature soldering to do LOM. http://en.wikipedia.org/wiki/Laminated_object_manufacturing
Point is machining is always needed if you do it this way and it’d be a bitch to machine
and you may as well mill it or use a lathe and a lathe and milling machines are still real reprap
It’s a neat idea, and I give them credit for seeing it through to a working prototype… But that’s about it. Their ludicrously rosy claims also severely undermine their hard work.
Bigger problems that need to be solved, overhangs/building over any cavity is impossible. So that means 100% infill. And every layer needs to be smaller or equal to the layer below. This is a fundamental problem with the mig/tig welding
@Tim_Rastall a small mig welder is like 30"x24"x20". At last I think that is the size of my dad’s, but I haven’t been home to use it in a while. The inert gas tank is the bigger item 12"diam 50" tall.