Isn't welding already FDM metal printing without the messy powder?

UPDATE: this seems to have already been discussed, so apologies for not adequately checking before posting here...


Just thinking aloud here...

If so:

(1) couldn't we just attach a welding tip to an end effector and have it build bead upon bead of material to create an incredibly strong metal part?
(2) what would the cost of parts work out with the current cost of welding rods?
(3) could wire with a much smaller diameter than welding rods be used to achieve parts with a better tolerances or finish?

Edited 1 time(s). Last edit at 10/03/2013 12:28AM by Senake.

Just checked...a 5kg pack of 2mm mild steel arc welding electrodes retail for £10+VAT

Mild steel, aluminium and stainless steel are all available as wire. Reels with 0.5kg steel or 0.3kg aluminium retail for around £15.

Aluminium and stainless seem to need MIG or TIG, but if a build chamber was enclosed, then maybe some of the inert gas (Argon) could be scavenged into a holding container between prints. Argon costs around £160/20L in a rent free bottle.

Short Circuit Transfer is generally used for thinner metals. Spray Arc Transfer
(generally used for thicker metals.

Wire feed speed indicative of feed speed onto 0.8mm thick metal is apparently around 70-80 ipm (inches per minute).

Some thoughts on 3d printing by arc welding. I think arc welding (MIG specifically) can work like an extruder for 3D printing but with some differences/limitations:

- Bridges cannot be done
- overhangs will probably be limited to much smaller angles, probably 10 degrees from vertical at most
- warping will probably be much worse than it is with plastics unless a very high temperature chamber is used, probably over 400c for Aluuminium and much more for steels
- the print cannot be made to detach from the build platform, so the build platform would need to be a new metal plate each time which then becomes part of the print.
- the slicer would probably need some more intelligence with regard to heat control, that is laying down material in a sequence optimised to reduce warping and other heat related problems. With metal I see this being much more critical than it is with plastics


The major costs of each print will probably be the electricity and the argon gas rather than the metal itself (welding wire).

The argon gas consumption could be greatly reduced by having a sealed build chamber . (which probably be needed in any case to maintain the high chamber temperature economically). The chamber would be purged and filled with argon just before the print and just topped up for any leakages.

The heat given off from the welding arc would probably be more than sufficient to maintain the chamber temperature. The temperature would probably need to be controlled by a thermostatically controlled heat exchanger.

Hello,
I don't think printing as per mig welding is feasable really as distortion due to the temperatures involved would run out of control during cooling.
trustytrev

Arc welding processes as utilized today are not suitable for addtive manufacturing, especially in an FFF application. Not to discourage any thinking toward that end but it's not a point of debate. One would be encouraged to look at how exactly a gas-metal arc welding process works (thermal reaction, mechanics, etc) and then look at how additive processes like DMLS and SLS work and compare the processes to see what the differences are between them.

Already being done industrially:

[youtu.be]

Part finishing requires additional CNC machining.

Good example. That app is electron beam welding and not gas metal/tungsten arc welding. Were one to look at the processes it's apparent that the electron beam is more similar to the laser sintering designs as it's easier (or in this case possible) to focus the beam in such a way the arc is capable of additive manufacturing.

Just FYI, you can use CO2 instead of Argon for MIG Welding which is much cheaper but you get more splatter.

I think the problem is resolution. If you're willing to accept a two-stage manufacturing process, with additive machining (MIG welding in electron beam mode) followed by subtractive machining (CNC milling), there's a lot of possibility to this.

Annirak Wrote:
-------------------------------------------------------
> I think the problem is resolution. If you're
> willing to accept a two-stage manufacturing
> process, with additive machining (MIG welding in
> electron beam mode) followed by subtractive
> machining (CNC milling), there's a lot of
> possibility to this.

That's precisely what Sciaky is doing: [www.youtube.com]

---

[haveblue.org]

This was done in the late 90's in Portugal. Check out the pdf..some pics at the end. The part had to be cleaned up after, but much faster overall than machining the whole part from a block of steel.

pdf

@Have Blue, Yes, I know that Sciaky is doing that, but two-stage machining is, so far, not accepted in the 3d printing world, so it bears pointing out.