New Material Idea

An idea I have been thinking of for a while...

As an extrusion material, using ABS or polystyrene plastic dissolved in acetone. This would be done using a 'plunger' type system similar to the one used in the fab@home project. This would have a few benefits:

1. You could recycle old plastic from packing peanuts, toys, etc. that would otherwise end up as garbage by dissolving it for extrusion material.

2. You could experiment with different viscosities by adjusting the plastic/solvent ratio to find an ideal 'goo' for extrusion.

3. No need for heating/melting the extrusion material.

I have the feeling that something like this was tried earlier...

I think it was Forrest that tried dissolving ABS in Aceton

can't remeber properly

'sid

PS iirc it wasn't such a big success

It worked okay. There was the problem of acetone being a bit of a fire and fume hazard, though, that made me doubt that it would be a technique that would work too well in somebody's home.

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On a related note, how about this idea in reverse. Powdered ABS plastic that uses misted acetone to fuse it together. In theory you could use an ink jet printer to do this. It would also mean less acetone is used and is sealed up in a container. Also, because the amount of acetone is small, it might even dry in a reasonable amount of time.

Weird; I saw an ad on TV for a children's art toy that uses plastic beads covered in water soluble adhesive, wetted with spray bottle, to build objects. I immediately thought that it could be a basis for a fabricating machine, but the beads seemed too coarse and the water soluble glue seemed not permanent enough.

Has anyone attempted a home-built powder material machine?

Don't know about you guys but aero-soling or atomising acetone sounds to me like a quick way to creating an explosive mixture.

On fume control, drying and acetone recovery I think there are some principles that could be borrowed from vacuum still technology.

Ie fab inside a box or chamber that is sealed apart from a vacuum outlet and a valved inlet which keeps the contents at a fixed negative pressure, say 0.5 to 0.75 bar or so.

If the vapour drawn out of the vacuum line is cooled enough it will condense before it hits the vacuum pump.

No explosive atmosphere other than in a controled space, acelerated drying and full solvent recovery.

Great theory, but could it be done in practice ?????

Thoughts for what they are worth

aka47

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Necessity hopefully becomes the absentee parent of successfully invented children.

Home built powder machines aren't that hard to make. It is essentially an inkjet print process. HP even sells empty inkjet cartridges that you can fill with glues to spray out.
So you rake a layer of powder out over a plate, spray the print area with glue, lower the z axis a bit, rake powder over the plate, spray glue, and so on until you have your finished piece.
Of course, the powder makes a huge mess when you have to load the machine.

As for the acetone method, I'll let someone else blow their house/lab up.

You could do the sprayed acetone thing in a sealed tent filled with pure nitrogen.

Or you could make fire a part of the process; put an electric spark igniter under the ink jet nozzles. Any patents on fire-sintered plastic fabricating?

Or just experiment with fire based digital printing; I bet no one's tried that yet.