I have been wondering about 3D metal printing (steel, aluminium), but after a short research on google I found only too expensive printers (markforged, desktop metal and a few other industrial ones). Is there any less expensive printer that is able to print metal parts on the market ?
Printing metal (directly) is done in mainly two types:
- Laser Sintering (LS), where a metal compound or alloy is sintered into form. For example, Tungsten Carbide is Laser Sintered. Common shorthands are SLS, DMLS, and SMLS, but others crop up too.
- Laser Melting, where the laser actually smelts the metal into spot. DMLS/DMLM (direct metal laser (s)melting) and SLM (Selective Laser Melting) are currently the top of the development.
There is a side market of a special setup that welds objects, making the whole item a single weld, but that is (strictly speaking) not printing, it is welding.
What bars the availability of OpenSource machines: Patents, more patents and even more patents are still running, and some of these patents contain parts essential to metal printing, so they are barred. Only a few key patents for Laser Smelting/Laser Sintering/Laser Melting like this one did expire at all up to now. Some of the nowadays relevant patents for METAL printing like this (exp: ~2019-2024), this (exp:~2037) or this new one (exp: ~2035) still have years to go, so it will take some time.
Another factor is market: There is only a small market for hobbyists demanding metal printers while the industrial demand is large, and the industry is willing to pay big money. So there is little pressure on the big ones to make small machines, while the open source groups need to develop ways that get the right results without breaking patents.
A more complete history of metal laser printing (and a little more help which patents actually are relevant for industry) can be found here.
Anzalone and friends published A Low-Cost Open-Source Metal 3-D Printer in IEEE Access:
This paper reports on the development of a open-source metal 3-D printer. The metal 3-D printer is controlled with an open-source micro-controller and is a combination of a low-cost commercial gas-metal arc welder and a derivative of the Rostock, a deltabot RepRap. The bill of materials, electrical and mechanical design schematics, and basic construction and operating procedures are provided.
You can create a metal object via metal casting or using a special filament containing metal parts.
You print with a special filament that contains from mixture of metal and plastic. After the print you heat up the object around 450°C to burn plastic away and melt metal grains together. You need a kiln. DIY kiln is about 150$.
The only filament I know is Filamet from The Virtual Foundry. CopperFill from ColorFabb contains just 30% of metal in oposite to Filamet containing 80%.
- virtual foundry youtube channel
- review: https://www.youtube.com/watch?v=hDIUCzV1vMg
- Copper Filamet™: $ 110.00 / 1kg
- Bronze Filamet™: $ 165.00 / 1kg
- Stainless Steel 316L Filamet™: $ 248.00 / 1kg
Just remember that these filaments are pretty dense which makes 1kg spools quite "shorter" and thus even more expensive!
This method is very closed to lost-wax casting. In short you print an object, surround it in clay/green sand, heat it up to burn out plastic and pour liquid metal in.
You can find an example of this tech on youtube, but the method is pretty much the same as with lost wax casting.
I have found some metal printing experiments in the RepRap projet, but did not study them in detail.
Bronze paste & paste extruder
This is just an idea: You could arguably take a FFF printer with paste extruder and print with a paste containing a high amount of metal in a paste. Then the print is processed in a kiln.
Here is a list of metal print technologies by all3p.com An example from the list:
- Desktop metal
- Markforged Metal X
- Digital Alloys
You can do lost-PLA investment casting, the actual gear to do it is kind of pricey unless you're willing to create your own DIY forge for melting aluminum.
Check it out though, you don't need a special printer to do it.
There's also a way to coat your prints with metal it would require an electric current and some nasty chemicals, but it's possible as an alternative.