Designing an FDM extrusion head for Aluminum?

Hi All,

I've spent the past few days searching to the end of the internet and back and I haven't really found any useful information regarding 3D printing of Aluminum using the FDM extrusion technique. As we know, all of the hobbyist 3D printers including the RepRap use FDM for extruding plastic but why cant this same basic concept be used for printing metal such as aluminum? Has anyone tried anything remotely like this?

The basic concept would be using induction coils to heat the the hot end of the extrusion head to above the melting temperature of aluminum. For example, a tungsten extrusion head could be wound with copper coil and imparted with high current AC to heat the tungsten up enough so that the inside diameter where the wire will feed through is above the melting temperature of aluminum. The extrusion head would neck down to a 0.4mm nozzle diameter and used to print just like a standard 3D printer for plastic. The build chamber could be purged with inert gas or a simple vacuum could be used to prevent the formation of oxide on the surface of the solidifying aluminum.

Now I know that with plastic 3D printing the plastic filament doesn't turn liquid but gets soft and is easily controllable. That being said, the aluminum would wan't to liquefy but would this really matter with an extrusion nozzle diameter of only 0.4mm? It seems like this would be a small enough liquid puddle to control with good accuracy. 3D printing is possible by using MIG and TIG weld torches and their weld puddle diameter would be much larger than what I'm proposing. Even so, if the liquid issue with aluminum is insurmountable, there are other alloys of aluminum that do not turn to liquid all at once and actually stay somewhat gummy. This might be easier to manage than liquid aluminum.

I guess what I'm saying is why hasn't this been attempted before? It seems like a very simple and affordable way to 3D print aluminum. Or perhaps I'm not seeing something?

... materials for FDM have a pretty big 'transition zone' between solid and fluid, where they are 'soft' enough to extrude, but won't flow away while layed down.

Metals have a really small transition zone, so not direkt usable for FDM ...

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Viktor
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VDX
... materials for FDM have a pretty big 'transition zone' between solid and fluid, where they are 'soft' enough to extrude, but won't flow away while layed down.

Metals have a really small transition zone, so not direkt usable for FDM ...

I don't think the extruded aluminium would flow away very fast, because the solidified previous layer would conduct the heat away very rapidly - after all, aluminium is a good thermal conductor. So perhaps it would be feasible.

There remains the problem of what to print the first layer on. It might be worth trying a sheet of of hexagonal boron nitride, which is a ceramic that has good thermal conductiviy but doesn't stick to most things very well.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

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mdowns8357
Has anyone tried anything remotely like this?

There are several examples of working FDM using solder or low-melting-temperature alloys (see links below). None that I know of use aluminum, although electron beam additive manufacturing can use a wide variety of different metal wires for source material.

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Read Before Posting - Technical Questions and Answers

25. Has anyone thought about 3D printing metal?
Yes. There are many established technologies for 3D printing metal parts, but most of these are beyond the reach of individual experimenters. There are many groups working on accessible low-cost technologies for 3D printing metal. Please see these working examples: A new approach to printing metals, Metal printing on a Lulzbot, Fused Deposition Modeling of Metals, Metal Delta RepRap v1.0, and these forum threads: Metal FDM thread, Metal-print Reprap, 3D Metal Printer Projects?, Induction Heated Nozzle, 3D Electroplating?, and these other resources: Metalbot.org, and MetalicaRap.

26. Can you extrude ordinary metal solder with a RepRap?
Yes. See First Reprapped circuit and Metal printing on a Lulzbot.

27. Can you extrude low melting point metal into grooves in a 3D printed plastic part?
Yes. See Multi-material freeform fabrication of active systems, First Reprapped circuit, and Syringe pump metal extruder.

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mdowns8357
The build chamber could be purged with inert gas or a simple vacuum could be used to prevent the formation of oxide on the surface of the solidifying aluminum.

A "simple vacuum" is not good enough. It has to be a "high vacuum", approx 10^-4 Torr. Amateur experimenters can build systems that maintain high vacuum, but it is not a simple thing to do. An inert gas build chamber is probably much easier - you might like the DIY anaerboic chamber described in these metal powder 3D printing experiments: Powder vs 50W laser diode

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mdowns8357
For example, a tungsten extrusion head could be wound with copper coil and imparted with high current AC to heat the tungsten up

You might like this very cool induction-heated nozzle project described here: Induction heating for 3D printer

Edited 1 time(s). Last edit at 07/11/2016 09:59PM by MattMoses.