Idea: A blacksmith bot based on Simpson

Imagine a Simpson type format robot with the ability to shape metal into near net shape. I propose such a robot could use 2 simple toolheads to accomplish this:

One tool head equipped with a wire feed (much like a filament feed) and a cutting solenoid. This tool head would push out wire downward into a bed of styrofoam (or other material that would hold the wire) at varying lengths, depending on the topography of the part being printed. Each XY coordinate on the print bed would be handled this way until a "bed of needles" is formed with the rough topography of the part being made.

The second tool would be equipped with a small propane torch and a tiny ballpoint hammer, actuated by a solenoid. After the first tool is done placing each wire, the group of wires would be clamped together. Then the second tool would be used to heat and then hammer the wires downward into the final shape of the part. Each small hammer blow would "upset" the wire so that it would expand slightly, filling the gaps between the wires, effectively forge welding the wires together. Once the top of the part (the part with details) is complete, the part could be turned over to each side so that it too could be (welded).

Advantages (that I can think of):
Low motor strength needed (compared to other CNC machines)
Open control scheme, like other repraps
Uses a robot that could then be used for normal 3d printing
Shapes metal!

Disadvantages:
Limited part shape (can be overcome with multi-piece parts)
Probably pretty loud (compared to a regular 3d printer
Manual intervention required mid-print (going from toolhead 1 to toolhead 2)

What could you make with such a machine? I think the largest potential would be moulds for other parts. If you were willing to assemble a few parts together then you could probably make quite a few things.

Hello Dudesom

That is a very imaginative idea, but I believe the wires would flex at every hammer hit. I think that using only the torch woulw be better, only fusing the ends of the wires thogether, but even though, I belive the parts made that way would be very delicate.
Maybe putting the complete part on an oven that fuses all the wires or even better, filling the voids with epoxy or some kind of resin could make some useful parts. It is potentially a new manufacturing method, albeit only useful for some kinds of parts.

By the way, IMHO that could be achieved with any printer, not only Simpson.

Well not any printer. Few printers have stationary beds (which I think would be desirable). It's true I could use a rostock but the issue there is that most of the print volume for those machines is in the x axis (if I'm not mistaken). Without a hammer, though, you're right, any bot could do it.

I think that for very small wires there would indeed be some flexing issues but, if one used larger gauge wires and a very very small "hammer" (small but fast!) I think it would be worth the (theoretically) increased part durability.

As for adding other fillers, yes that is an awesome idea. This way you get the surface hardness and durability of steel (or whatever). Thanks for your input!

If there are any machinists out there who care to chime in, I'm curious if this small hammer approach could be used to work harden as well, after the initial weld. Would this lead to better material characteristics?

Dudesom, you might have some success with ultrasonic welding. I think you're going to have difficulty getting the metal to adhere, though.

Check out thermosonic welding. It's the process used to bond wires to ICs. Ultrasonic welding is also used to bond plastic cases together.

That does look interesting. And expensive I wish I could try some of that stuff but I don't see it--along with lasers and arch welders--being in my budget any time soon.

At the moment I'm thinking about possibly spot welding and alternative robot designs to the Delta type (lathe style polar looks possible). When I get a little time I'll start a new thread someplace I guess.

It's too bad someone's already named their reprap "Blacksmith"

Edited 1 time(s). Last edit at 09/06/2013 08:27PM by dudesom.

I know I have been banging on about this for some time, but why not use small ball bearings. (ballpoint pen size)
and have a bank of capacitors, place each ball and zapp weld to the previous ball. infiltrate if needed.

Must get around to building it one day.

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Wirebonding, spot welding, and other techniques were discussed quite a bit in this thread a while ago. VDX mentioned some experiments he did with ultrasonic wirebonding and pointed out several difficulties with using the process for freeform fabrication.

@johnrpm that's almost exactly the idea behind voxel printing. Though using electrical discharges for welding would certainly be novel.

I just have too many things on the go to do it, but if you have seen pnuematic air filters, the part should look similar, bone would adhere, so good for implants, all sorts of other things come to mind, but the tech is doable.

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If you're going that route, you could to fine-gauge MIG welding. If you can get the right mode of welding, the arc actually transports the metal to the work surface.

Not sure what kind of resolution you'd get, though.

Tried the mig welder thing some 20 years ago, Krupp have it patented, but as far as I know no patents on the ball bearings, if fed down a single tube at first, with an arresting collet, as each ball is welded the next ball takes its place, when the teathing problems are ironed out, a linear array may be employed.

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Also check out Jeff Thompson's work on voxels. He did some experiments using a CNC to build things out of spheres.

If you could come up with some kind of collet to hold the sphere, you could spin it like crazy and use friction welding. It may not have any advantages over spot welding, but some combination of spinning and zapping might work better than either alone. For example, spinning the sphere might help clean the surface of oxides and other junk at the points of contact, thus resulting in a much higher quality spot weld.

Interesting stuff, I can not see the image though, I had thought of modifying the weld for support balls so they break away easy, but his idea of a sacrificial ball is worth trying.

Sorry to highjack this thread, one day I will try it out.

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It's ok. There must be something really wrong with my idea I think, because I can't find anyone who's tried anything remotely like it.

Edited 1 time(s). Last edit at 09/12/2013 05:47PM by dudesom.

dudesom
Have you seen those pin blocks, where you put your hand into them and it keeps the shape, I imagine your idea like that, I have seen special vices with an array of adjustable pins to hold awkward items, and I saw a
similar device that has cnc controled pins with a flexible top sheet, it could create sone nice curved shapes.

I should have said pneumatic silencer not filter,

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