Wire 3D Printer

A 3D printer for printing with welding wire

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This is my attempt to build a 3D printer for printing metal. The wire gets melted by high current which flows from the printhead across the wire to the buildplate. The current is created by an old microwave oven transformer with a 50mm² cable as secondary coil. The heating intensity is controlled by a phase-fired controller connected to the primary coil which can be controlled by the part cooling fan parameter of the slicer software. The printer is compatible with any FDM printer slicer software.

I started this project because I ever wanted to print metal parts since I bought my first 3D printer back in 2017, but there are still no affordable and easy to use metal 3D printers out there. The project is inspired by 

which also heats the wire with high current instead of an arc.

The printer is actually a FDM 3D printer built from an old microwave oven transformer and some other not special parts, which prints with welding wire instead of plastic filament. The only difference to a normal plastic FDM printer is, that the heat (around 1450°C) is created by high current flowing trough thin wire instead of plastic filament melting in a heated nozzle.

The printer is also suitable for welding/heating small metal parts.

Standard Tesselated Geometry - 526.06 kB - 03/29/2020 at 00:13


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  • Shielding Gas Upgrade Build Progress

    Dominik Mefferta day ago 0 comments

    I tested a TIG gas lens body which I want to use as new nozzle with an old vape pen to see whether the gas will cover the whole printing area. The hole in the middle will later be covered by the wire so that most of the shielding gas will likely exit the gas lens through the outer "ring".

    With this as new nozzle I can keep the printhead design as it is - It just needs a M10x1 thread for the new nozzle instead of a M6 thread.

    A possible issue with this could be that the shielding gas flows into the bowden tube instead of the nozzle, what maybe could be fixed with a 3D printed diameter reducing joint.

  • A day of testing and further plans

    Dominik Meffert4 days ago 0 comments

    Today I tested out the Z Min Probe Homing function and the bed leveling function. I noticed that the probing works very well as long as there is enough current for the switch to work and as long as the nozzle is not sooty - therefore the nozzle has to be cleaned with a steel/brass brush or a file tool before homing/probing and the wire has to be retracted in the nozzle.

    I also did a few printing tests, but unfortunately none of them worked out - mostly due to problems with the first layer, too much or too less intensity and clogging of the nozzle. The ability of homing and probing makes testing definitely a lot easier.

    I also tested using only the infill aligned to 90 and 0 degree angle without outlines like Digital Alloys do in their videos and it has the advantage that the printed lines fuse very good to each other when they get printed parallel to each other. That's because the last printed line gets heated by the line which gets currently printed.

    It's also an advantage that there is no outline in which the nozzle can crash.

    I think before the next testing attempt I will build a new printhead with proper shielding gas supply, relocate the water cooling radiator, install a solenoid valve + relay, mount a polycarbonate front plate and seal the sides of the printer for shielding gas use.

  • Probing with Current Sensor

    Dominik Meffert5 days ago 0 comments

    Thanks to Krzysztof for the idea of using the nozzle as probe.

    Because the thin steel sheet on the buildplate gets deformed due to the heat, the surface to print on changes a bit after every print. So it's needed to probe the buildplate, but unfortunately doing so is not so easy. The buildplate and printhead are always connected through the 50mm2 cable, so using them as simple swich would not work, but even if it had worked the controller board had needed a protection against the AC voltage. So I tried using a current sensing switch, which triggers the 

    Z Min Endstop when the current rises due to the nozzle touching the bed.

    It works for homing and probing. I likely have to decrease probing speed or increase intensity to prevent the nozzle from pushing the buildplate down a bit.

  • Shielding Gas again

    Dominik Meffert5 days ago 2 comments

    I retrofitted a shielding gas inlet to the printhead for more testing with shielding gas. At the moment it's just a hole next to the nozzle for spraying shielding gas on the buildplate and I'm not sure whether this is enough or whether I need a proper gas nozzle. I think I will see it while testing... I will also installed a solenoid valve for starting and stopping the gas supply.

    The valve can be opened in the startcode with e.g. M106 P1 S255 and closed in the endcode with M106 P1 S0. The valve I have works with 12V and so it would need a relay for operating it.

  • Welding

    Dominik Meffert6 days ago 0 comments

    I needed a few M3*40 screws, but unfortunately it was past 20:00 and the hardware store had closed.

    So I thought about making my own screws with the wire printer, which actually is just an advanced spot welder.

    The "screws" are made of stainless steel threaded rods and galvanized steel nuts.

    In the video I carefully increased the intensity what took a bit longer, because I tried it before with high intensity and it almost instantaneous melted the M3 Nut.

    So if you are interested in welding together or heating small metal parts you can use this printer for it.

  • First successful print and further plans

    Dominik Meffert03/26/2020 at 13:17 11 comments

    For the first time I could finish a print. It worked by reducing the extrusion rate after a few layers, so that the nozzle didn't crash in the part after some time.

    I think the problems with the first few layers came from the buildplate, which got deformed due to the heat. The melting point of steel is at around 1450°C, so there is a lot of heat on the builtplate.

    I'm planning to solve this issue by automatic bed leveling with an inductive poximity sensor which should get delivered later this week or early next week.

    Pictures of the printed object, in which you can see the printed layers and the difference in layer hight between the upper and lower layers.

  • Next Problem: Layer Hight

    Dominik Meffert03/25/2020 at 14:29 7 comments

    Now, that the wire feeder works reliable the next problem is the Layer Hight.

    When the nozzle is far away from the buildplate the hight of the melted material layer gets higher as it should. This would also not work by FDM printing.

    But when the nozzle is near to the melted material and the heat reaches the nozzle after a short period of time the wire gets stuck in the nozzle.

    I tried different settings and could print near the melted material without that the wire got stuck in the nozzle.

    It seems like as long as the feedrate is high enough the wire gets not stuck in the nozzle.

    The parts from the latest tests are also very strong. I tried cutting them with pliers and was not able to cut them per hand. I think they are stronger than plastic but at the moment a bit weaker than massive steel.

    The problem that remains at the moment is that after some time the "extruded" material reaches the hight of the nozzle.

    So far, I had the best results when the nozzle is as close as possible to the surface of the printed object but does not touch it.

    When the nozzle touches the surface the current flows no longer only through the wire, so that the wire gets less heated than it should and the "extrusion" gets brittle.

  • Wire Feeder Upgrade

    Dominik Meffert03/21/2020 at 22:52 3 comments

    Maybe I found the cause of all the problems:

    I just realised that the wire is randomly slipping in the wire feeder, so that the amount of "extruded material" was wrong the whole time and this could have caused all the problems I had with printing.

    That could mean there were no problems with heat, settings, material, (oxidation), just random amount of "extruded material". What a shame that I didn't noticed that earlier.

    Will change the design of the wire feeder for reliable operation.

    I designed a new wire feeder, but unfortunately it worked as bad as the last one.

    I also ordered a wire feeder roller for building a wire feeder that hopefully works. It will be delivered later this week.

    Here is the new feeder with the wire feeder roller and it works very well. The feedrate should now be as set in the slicer software.

  • Testing with Shielding Gas

    Dominik Meffert03/21/2020 at 22:25 2 comments

    I tried out spraying CO2 and Argon Gas on the melted metal while printing, but unfortunately I couldn't see any difference in print quality. Maybe I did something wrong or it has something to do with using resistance welding instead of arc welding. Will maybe test it again in the future...

  • The Problem is Oxidation/Contamination

    Dominik Meffert03/20/2020 at 18:15 0 comments

    Just tested printing with flux core wire and the first layer printed very well, but as soon as the second layer started the melting stopped completely - I think it lost its conductivity due to a layer of less conductive material covering the metal. With the steel wire the socond layer melted, but the melted material did not fused together...

    I also tested aluminum wire. It fused together but was very brittle.

    Will test thicker steel wire, maybe it helps when there is more melted material at once.

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Enjoy this project?



Adam Quantrill wrote 4 days ago point

Two ideas: for your welding shield gas be it CO2 or Argon, if you do your welding in an open-top "tank" then once you have filled the tank your gas will sit in there as it's denser than air. Looks like you are almost there with your build.

Second if you can spot-weld how about adding tetris parts with a robot arm and building up the shape with solid metal? Yes the voxel volume will be rather course bit that might not matter if you can grind the assembly afterwards.

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Dominik Meffert wrote 4 days ago point

Hi, I think I will relocate the cooling system radiator to a place inside the printer... maybe underneat the Z axis assembly and add a polycarbonate front plate, so that the air stays inside the printer.

That sounds interesting and would likely be a very unique machining method :)

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tyeth wrote 5 days ago point

As you're the new king of DIY metal 3d experimentation, and have talked about possible sealing of the chamber, I wondered in a mad moment how the reliability and lack of sticking might actually be improved underwater, salty water, as you'll really be able to stab that wire into the plate without risk of it sticking... I've heard you really have to apply force or drag it around to maintain a spark when welding underwater, but it was a random welding video ( ) using stick with a protective outer coating, still I think the same would be said using wire and mega-current, but safely inside a box...I'm curious and wondered if you might be too.

Keep up the great work either way!

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Dominik Meffert wrote 5 days ago point

Hehe thank you :)

Should I try printing under water?

The problem I see would be, if the water is conductive I think the current would no longer flow across the wire or at least less current would flow across it and maybe it would no longer melt.

But I haven't tested it yet.

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Jarrett wrote 5 days ago point

EDM machines use either distilled water, or mineral oil to get around the conduction problem

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Dominik Meffert wrote 5 days ago point

Yes, but he said salty water :)

A few weeks ago I saw a video of someone building his own edm drilling machine for which he also used distilled water.

I will try to print my own shielding gas shroud with the wire printer. This way I could stay with the contact tip nozzle and keep it simple.

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tyeth wrote 5 days ago point

Oh your absolutely right it will go through the wire and leech into the water too, but I believe that adds an interesting characteristic whereby the sticking issue is reduced and a more predictable behaviour is exhibited. 

Just curious, what's the highest current you've used so far?

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Dominik Meffert wrote 5 days ago point

I testet once at which point the breaker trips which protects the 50mm² cable from overheating with 7A input and 375A output.

I'm printing at around 1,5A to 2,5A input which should be 80A to 130A output what goes through 0.8mm welding wire.

By using more intensity there is a lot of arcing until the wire get stuck in the nozzle or the nozzle stops conducting due to soot on the nozzle.

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technophile.sw wrote 4 days ago point

Seems like there would be difficulties; if the results were great then a lot of welding would be done in tanks of water.

I'd watch for:

1.  Electrolysis:  generation of hydrogen and oxygen gas --> corrosion one side.  Also a combustion / explosion hazard.

2.  Cold joints.

3.  Increased shock hazard.

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Dominik Meffert wrote 4 days ago point

Yes, think I will continue working on a shielding gas option.

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Audiocrush wrote 5 days ago point

well regarding your argon/co2 endeavours:
When you use CO2 in your shielding gas, it will increase the carbon content in the liquid metal. Not sure which effect that will have, but I'd recommend going with argon 4.6 which should be sufficient.
Also take a look at common mig gun supplies for using as a shielding gas outlet.
Argon is quite expensive, so If you don't want to waste as much, I'd recommend you using a construction as close to a common MIG gun as possible.

In TIG welding I love to use whats called a gas lens, which makes argon flow laminar going out of the nozzle, which makes it an absolute joy to work with. Maybe you can find something like this for a MIG gun? not sure if it makes a difference but I can imagine everything which takes variations and chaos out of the equation will make your results much more consistent and predictable.

Love the project :)

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Dominik Meffert wrote 5 days ago point

Hi thank you for your advice :)

I think I will likely design a new printhead with a mig gun head or a tig gas lens with a contact tip in the middle to have the possibility to use shielding gas and keep it as an experimental feature. I have absolutely no welding experience and still never used a welding machine, so it's impossible for me to give a recommendation on shielding gas use.

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John Opsahl wrote 03/23/2020 at 19:08 point

I have seen DIY wire benders use welding wire feed rollers for the wire feeder. Might be a good place to start if you are considering adding one to your machine. See 3 minutes 20 seconds into this video:

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Dominik Meffert wrote 03/23/2020 at 19:21 point

Hi John,

thank you for the link. Will try to build something like this.

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jibril wrote 02/27/2020 at 02:25 point

I have not used my 3D printer in a long time

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jibril wrote 02/27/2020 at 02:23 point

your spool looks like the one on my 3D printer

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Wayne wrote 02/26/2020 at 17:12 point

Consider running the metal filament through a bowden tube or similar to reduce the chances of it unspooling and causing problems? 

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Dominik Meffert wrote 02/26/2020 at 17:15 point

Hi Wayne, yes it will run through a bowden tube.

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Klaus Kaiser wrote 02/23/2020 at 11:46 point

How do you prevent oxidation of the liquid metal? Do you use shielding gas and/or flux-core wire? 

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Dominik Meffert wrote 02/23/2020 at 15:36 point

Hi Klaus,

I thought about it, but couldn't test how oxidation affects the print quality until now. I think in the next few days the build should be ready for a test run. Actually I want to prevent using shielding gas to keep it cheap and simple, so the only option would be flux core wire, if oxidation is a problem. Maybe it could be a benefit that the wire heats up / melts from the inside because of the high current flowing through it, but thats only speculation.

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Tomas Mudrunka wrote 5 days ago point

Hello. I have some experience with wire welding and i think you really should do something to prevent oxidation, otherwise the printed object quality will be greatly degraded both in terms of physical and visual properties.

Also i need to strongly advise you to stay away from flux core. I leaves slag, which needs to be constantly removed before next layer can be welded on top of it.

Use CO2 gas! It's very cheap and easy to do. You can either provide constant flow of CO2 directed to your nozzle (in similar way plastic FDM printers use part cooling fans) or you can enclose whole 3D printer in watertight vessel and fill it with CO2 before printing. CO2 is heavier than air, so you can still have some openings at top, given you don't blow it too much. Only issue might be caused by pressure regulator freezing, if you use too much flow. There's no need for high flow if you use CO2 filled enclosure. If you need to have high flow for a long time, some people use warming devices. I saw people using high power resistors to heat up the pressure regulator. Quite easy. Also you can put electricaly controlled valve at low-pressure side(!) of the regulator so your 3D printer will be able to automaticaly stop the flow once the printing is done.

Go to any shop with welding equipment and they will tell you everything you need to know, it's really not that hard. Basicaly you need CO2 bottle, pressure regulator and some hoses.  Also you can get these things in shops who sell restaurant equipment, because the very same stuff is used to pour a tap beer from the keg.

I know it might sound bit uncomfortable at first, but i believe you will save yourself great ammount of trouble if you go the CO2 way rather than flux core.

Just remember to close the valve before you go to bed ;-)

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Dominik Meffert wrote 5 days ago point

Hi Tomas,

In terms of flux core wire you are 100% right. It behaves like you said and is not suitable for printing. In terms of CO2 I just added a inlet for CO2 for further testing. Do you think a hole next to the nozzle is enough or do I need a proper shielding gas nozzle to benefit from shielding gas?

The idea of sealing the printer and filling it with CO2 to the top is also good, but would require a relocation of the watercooling radiator.

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Tomas Mudrunka wrote 5 days ago point

The point is that the molten metal should be always covered in CO2, so it does not come in contact with the air. I am not really sure if single nozzle next to the wire nozzle is enough, but i think you can easily try it, if you somehow manage to inject smoke into the CO2 line (3d printed venturi and vape-pen?), so you will see, how the CO2 moves through the space.

You can take a look at commercial TIG torches and how they are made. I think it will give you some idea. It's basicaly big nozzle for gas and the smaller wire nozzle is in middle of it. But i think it might not fit nicely to your machine.

What if you take some copper pipe (brake line), seal one end (crimp with plyers and solder it). Then you can bend this pipe to "?" question mark shape. So you will have plugged end forming the ring around your wire nozzle and straight end providing inlet of CO2. You can then use tiny drill bits to make series of holes in the ring all around the printing nozzle. Dunno. Just idea.

Or just take a look at ducting part of cooling fan assemblies of FDM printers and make similar ducting from something heat resistant.

BTW if you have some watercooling system, you might run the hoses to pressure regulator of CO2 tank, because this gets really cool as CO2 gets to atmospheric pressure and warm water can help to prevent it from freezing, if you figure out how to exchange the heat between water and regulator. (Might still need to cool the water afterwards if it gets too hot)

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Dominik Meffert wrote 4 days ago point

Hi, I've ordered a tig nozzle which already has the holes for shielding gas and a thread for a shroud. Your ideas are also good. When I have the new toolhead ready I will test it with fog to see whether it covers the pool of melted material.

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Bharbour wrote 02/05/2020 at 14:34 point

How do you insure that the wire disconnects from the welded spot? It seems like the opportunity to just weld the head in place is very high.

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Dominik Meffert wrote 02/05/2020 at 14:49 point


It should be as followed:

As long as the electrode is made of copper it should not weld to the workpiece. The most heat is generated at the point of the greatest resistance, so the copper electrode stays cooler because of its low resistance and greater diameter and should not melt.

I tested it many times and it never welded in place.

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Bharbour wrote 02/05/2020 at 20:40 point

I meant the welding wire not separating from the welded spot

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Dominik Meffert wrote 02/06/2020 at 01:27 point

Yes that could be a concern, thanks for the hint. I will test it and if the head welds to the welded spot I will maybe need another nozzle with an orifice shifted inwards or something like that.

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Martin wrote 01/28/2020 at 16:09 point

I remember a project, a friend did in the late 1990ies. In that time they called it "rapid prototyping" and not so much 3D printing. They tried to melt metal like iron with an induction coil or some welding torch to build up an object layer by layer.
But that led to massive thermal distortion. AFAIK they tried even grinding each layer with a good (6 axis) CNC mill, but in the end they could not design a reliable 3D printing process.

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Dominik Meffert wrote 01/28/2020 at 19:45 point

Hi Martin,

I think that's the thing with metal 3D printing. Many people have worked on it, but only a few companies were successful with complicated and costly methods. It seems like it's extremely hard to get usable results at low cost.

The objects which I want to print/weld will likely be more partially together welded wire parts than solid metal parts, but I think it could be a cheap way to create 3D printed/welded parts at all. Maybe later the process can be somehow improved to create solid metal parts.

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technophile.sw wrote 4 days ago point

Post-print cleaning and electroplating?

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Dominik Meffert wrote 4 days ago point

Maybe when it works more reliable.

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Wayne wrote 01/25/2020 at 22:09 point

Very cool, have wanted to see a 3D printer operate like this. 

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Dominik Meffert wrote 01/28/2020 at 21:01 point

Thank you,

there are still some things to figure out but I think it should work.

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Dan Maloney wrote 01/14/2020 at 18:08 point

I really like this idea. I can see it starting out really simple, with wires tacked to the build plate to make "low poly" shapes. Then you increase the number of spot welds to improve the resolution, and then build up layers. Really cool idea.

One place you might have trouble is the duty cycle of your spot welder. You might have to build a pretty beefy welder to keep it more or less continually operating.

Good luck, and keep us posted.

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Dominik Meffert wrote 01/14/2020 at 20:07 point

Thank you,

I hope I can build a capacitor based spot welder that can work for hours, like a 3D printer. Maybe with multiple capacitors to switch between them for reducing time between two welds and for using double pulse spot welding if needed.

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technophile.sw wrote 4 days ago point

What would you be spot welding?  I understand spot welding as joining two or three objects pinched together between (usually large) electrodes that run a heavy current through them.

Are you thinking of capacitive discharge welding, maybe wire-feed?

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Dominik Meffert wrote 4 days ago point

Hi, I started this project as a cnc spot welder,

but the machine is still capable of spot welding

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