Oil Bath
October 22, 2007 05:20PM
I was sitting here minding my own business when a thought struck me. I took a small piece of both HDPE and UHMWPE into the kitchen and dropped them into cooking oil. both sank extremely slowly. When I repeated this with dimethicone instead of cooking oil, the HDPE was actually buoyant. The UHMWPE still sank but just barely.

Why was I doing this? It occurred to me that, if you had a liquid bath of roughly the same density as your build material, a support material becomes unnecessary. You could also draw lines in 3-space (i.e. all 3 axes moving at once), rather than just on an XY plane.

Of course, extruding plastic in an oil bath introduces all sorts of logistical problems: anchoring, heat dissipation, general messiness. Probably causes more problems than it's worth, really.

Still, if and when I get my machine built, I might have to try it, just once.
Re: Oil Bath
October 22, 2007 05:23PM

That's an interesting idea. Has anything like that been done before? I mean to ask, will you have to completely invent a new process or can you use previous work?

Re: Oil Bath
October 22, 2007 06:19PM
Hmm, can't tell if anyone's done this before. The closest I could find was a selective curing process where the liquid medium is also the build material.
Re: Oil Bath
October 23, 2007 01:50AM
... most liquid-curing RP-systems activate the surface of the liquid epoxy through an UV-laser or LCD-beamer-focus, so you build slices on slices as normal - but you have to build supports too, or your hardening parts would crumble, if you move the basis-platform in the bath and move the washer to make the surface plain after overfilling ...

I had similar thoughts - when the curing area would be a small point directly before a tool-tip (laser-head or high-frequency-microantenna for heat-curing), then i could flood the working area completely and move the curing-spot 3-dimensional inside the liquid to make a free form.

But i have to build supports too, if through turbulences while moving the builded structure would be waving ...

Re: Oil Bath
November 04, 2007 11:13AM
At the very least, doing that might increase the angle you can build at. For example you could probably build an upside-down top-hat shape.

Whether it's worth the limitations in building materials is another question though.
Re: Oil Bath
November 14, 2007 03:13PM
Interesting, although there doesnt seem any reason to stick to solely support materials. You could make the bath a polyol and then extrude liquid hardener into it, making a quick and dirty (and I mean really DIRTY) protoyper with no need for support mateial and the ability to build in X Y and Z at the same time.


The views expressed in this post is not that of my employer. Attempts at implimenation are at your own risk.
Re: Oil Bath
November 26, 2007 06:56AM
Mike I thought along the same lines as you.

having a vat with the cheap catalyzer I'm developing and printing Furfuryl Alcohol or Furfural threads on top of it, then dropping the layer a level. it would make for a ruff prototyper if we can solve the problem of enclosed volumes in the 3D models.

It's like a SLA (stereo lythography) but without lasers.
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