Society of Robots - Robot Forum
Mechanics and Construction => Mechanics and Construction => Topic started by: drcrash on July 16, 2007, 03:34:09 PM
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The vacuum forming tutorial makes it sound like a vacuum former has to cost $500 or so, even if you make it yourself.
I wrote an "Instructible" (how-to) on how to make a good, cheap, upgradeable vacuum former for under $50, using your kitchen oven and a vacuum cleaner:
http://instructibles.com/id/E8RW98YF3C4XLCQ/
Here's a movie of it in action:
(http://i136.photobucket.com/albums/q176/drcrashpix/miscvacuumforming/th_10c156de.jpg) (http://s136.photobucket.com/albums/q176/drcrashpix/miscvacuumforming/?action=view¤t=10c156de.flv)
You can add a standalone oven made from a two-burner hot plate and disposable aluminum pans for under $30.
You can add a high vacuum system for forming thick plastic for about another $50.
This stuff and more is linked at the Vacuum Former Plans blog at www.VacuumFormerPlans.com
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Excellent video. Clears up some of the confusion I had from the written version of the instructable.
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I don't know too much about vacuum forming... but do you know what the maximum thickness of plastic you can use to make parts out of?
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I don't know too much about vacuum forming... but do you know what the maximum thickness of plastic you can use to make parts out of?
With a simple easy setup like in the video, you can form plastic up to about a quarter of an inch thick. I've made parts the size of the one in the video that my wife and I can both stand on without breaking them. (Of course the rigidity & strength depend on the shape.)
When you form thick plastic as shown in the video, without a high vacuum system, you don't get very sharp detail---the shape gets smoothed out by the thickness of the plastic, and somewhat more.
You can get better detail with a high vacuum system, which pulls several times harder than a vacuum cleaner. (You can use a converted bike pump, or electric tire inflator, or kitchen food sealer, or a "nebulizer" pump from a thrift store.) For maximum detail, you want to suck the plastic into a concave mold, rather than draping it over a positive mold as in the video. (The side of the plastic that's against the mold has the best detail; the other side is smoothed out more.)
I'd think that for most robot purposes, plain vacuum forming of 1/8" plastic over a positive mold with a vacuum cleaner would be fine---you can make smooth compound curves with curve radii of about 3/16" for convex stuff, or 3/8" for concave areas. (Somewhat finer detail does show through, but in muted form.)
People seem to like rounded-off robot stuff, and the parts are generally convex, so a cheap easy vacuum forming setup can be very useful for making your bot look professionally made.
With a fancier setup, you can form plastic up to 3/8" or 1/2" thick, but I think that's overkill for most robot purposes, and I haven't tried it yet.
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Excellent video. Clears up some of the confusion I had from the written version of the instructable.
Let me know what you found confusing. (I intend to edit the Instructable. It was a bit of a rush job, and should have had the video to start with.)
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Impressive!
Wish you made this video 2 years ago! :P I would have definitely done this.
You might want to go in to more detail about creating a proper vacuum - I found this to be the hardest part.
Just for reference:
http://www.societyofrobots.com/materials_vacuumforming.shtml