By the way, if you want to move to resistive melting, I suggest starting with coreless solder. It has low melting temp so shouldn't require too much energy, but one problem - sticks to copper really well, but that could be prevented with lightly greasing the electrode.

Good idea, I already ordered welding wire and flux core wire for testing. Will order stainless steel wire and coreless solder, too. I'm planning to get the spot welding process done and after that I want to try continuous welding, so that if the wire touches the workpiece it melts/welds.

But I think this would require good cooling of all parts, the beefier power supply and maybe software for controlling it.

That will require much beefier power supply. Also looks like halfway between your old method and digitalalloys, I hope it will work.

Yes that could be true, I don't know at the moment how much energy is needed for softening and melting the wire all 1-2 seconds or faster. Would like to use as less energy as possible. Hope I can figure it out by testing and will accordingly change my power supply setup, so that no part of it overheats. On the last test with 250ms pulses every second with ca. 2645W the resistor block and also the cables became very warm, so that it could not run for longer times. If the same or more energy is required I will change the setup for more energy. Also thought about continuous welding, so that the resulting parts could be stronger, but first it must work at all and then I will see.

Yes from the outside it now looks more like digitalalloys' printer, but what they are doing is on a much higher level. They build up solid metal objects from voxels of molten metal and observe and adjust every single parameter, which is amazing, but way overkill for what I want to achieve. If it works out to print/weld metal objects at all, I would be very happy. 

I think you misunderstood their video. Their printer works just like any fdm printer, they just MEASURE and store quality data in voxels. It's just optimised version of normal printer, but instead of metling media in chamber, it's melted right in place where it's deposited.

Ok, I guess I got it wrong. Thank you for telling me :)

I thought it must be more complicated. And sorry for asking again, but why has eg. no one with a welding background ever added something like a seam welder power supply to a 3D printer and just did this?

If such a printer like digital alloys' would be available for everyone it would create completly new possibilities in manufacturing for makers and small companys.

It's not like no one did, I've seen it made several times, just with arc welders/MIGs, like this old tony https://youtu.be/sFXniBbgbw0?t=323 there are more examples but they are harder to find. D/A just invested more into resistive melting technology. Those guys want to print entire rockets https://www.youtube.com/watch?v=R5mhUm6NzqE and several "artists" 3d printed a bridge using a welding robot https://www.dezeen.com/2018/10/22/worlds-first-3d-printed-steel-bridge-completed-mx3d-technology/

Thank you for sharing this with me. I've seen many videos in which people used arc welders for 3D printing with mostly poor results and I saw a youtube video of someone who showed resistance welding of a wire without completly melting it with good results like 3D prints made of wire (but the video got deleted by the creator) and the video from digitalalloys.

It looks like the resistance welding method works way better than arc welding without the need of shielding gas.

So there were two "resistance heating 3D printing projects" I could find from which one disappeared.

That's what I meant.

Maybe it could be because resistance welding is less common than arc welding, but I don't know.

> why has eg. no one with a welding background ever added something like a seam welder power supply to a 3D printer and just did this?

Probably because it requires some control over power, like with extruders, it's not just simple "glue gun", but requires coordination from software and several kilowatts of power required for melting wire with reasonable speed (you can't be too slow, otherwise heat spreads too much) is hard to control with simple electronics.


>Maybe it could be because resistance welding is less common than arc welding, but I don't know.

This is also one of reasons.

Ok, that could be the reasons. Thank you very much for talking with me about this topic. I think I will continue working on my spot welder for hopefully creating usable results or at least some experience which I can share :)