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arrow
09-02-2008, 04:24 AM
Any thoughts on the modification of a shopbot to do Incremental sheet Forming?

Metal Sheet Based Fast Prototyping via Incremental Forming Technique:
http://www.youtube.com/watch?v=KuR_fnZ9JvI

2:27

http://en.wikipedia.org/wiki/Incremental_sheet_forming

Brady Watson
09-02-2008, 11:02 AM
I'm sure that it can be done to a certain degree if you have perfect alignment of your mold & the machine. I would try this on an Alpha, but probably not a standard unless you had 7.2:1 motors, as the process requires a decent amount of force.

If I were attempting it, I would start with .040" AL sheet, an MDF plug 3D machined to the desired shape - which has been offset & radiused to the inside @ the material thickness.

I'm sure that if someone took the time, and really had the need, it could be accomplished within a few months.

-B

gabepari
09-02-2008, 01:52 PM
It looks like the plug raises into the sheet as each level is completed. Or the sheet clamps would need to be lowered on each level...

Pretty cool. Almost like metal spinning, but for non lathe-able shapes.

Gabe

Brady Watson
09-02-2008, 04:52 PM
I think the sheet is bolted down around the perimeter of the mold. I bet that a little vacuum would help keep the already formed metal stuck down to the mold. Either way, it's an interesting way to produce sheet metal goodies
How realistic it is for a small shop is yet to be known until someone actually tries wholeheartedly.

Gabe - I was thinking the exact same thing...Might not be good for shapes that could be done on a spinning lathe, but may prove to be useful for other shapes. I wonder how feasible it would be to do a car fender or something like that this way. In theory it doesn't seem to bad, but assumption is the mother of all mishaps.

-B

stevem
09-02-2008, 05:35 PM
This looks like it needs quite a bit of downward force and a slow speed spindle, like that found on milling machines. It would also require a stiff frame and a way to keep the gantry from being pushed off the V rails.

Brady, this is looks like the ideal way for making one off fenders or custom parts in sheet metal. Think gas tanks for custom motorcycles.

arrow
09-02-2008, 06:39 PM
Sheets of pewter or lead might be an ideal material to experiment with.

Brady Watson
09-02-2008, 07:32 PM
Steve,
It's hard to tell in the vid if the stylus/tool is actually spinning or not. It seems to me that it could be done on a non-rotating ball-ended tool with no cutting edges. I think that it is essentially rolling the material, pretty much like metal spinning. What I don't know is how much stretch there is with the material & if you need to consider this when 'drawing' a part over the mold to prevent tears.

You are definitely right...the CNC's chassis would have to be beefy & this whole process might only be suitable on something like a heavy CNC mill.

-B

paco
09-02-2008, 07:52 PM
The ball tip is lubed. There's oil all over the being formed metal sheet. I don't think it's revolving...

paco
09-02-2008, 07:55 PM
Oups! (http://www.youtube.com/watch?v=GxysBla3NyI)

robert_cheal
09-03-2008, 11:36 AM
After seeing the video links yesterday my tail is still wagging today. I am wondering about light duty (low relief) decorative options. I don't know if this would work using this same method, for example I wonder about a thin gauged copper pressed into a negative MDF plug. It could be letters in a sign, a decorative design in wall plaque, cabinet door panels, etc.
Then the metal could be antiqued, burnished, etc.
If the metal is too thin to be worked on, the back side could be filled in with glue or resin.
Just wondering.

Robert

chiloquinruss
09-03-2008, 05:04 PM
How about using a combination of the spinning stylus while applying a vaccuum to the sheet? It sure does sound like a neat way to make some ornamental pieces as was stated above. Hmmmmmm!
Russ

arrow
09-03-2008, 06:07 PM
I wonder if the same process would work on sheets of plastic or some type of clay material. Forming downward into a bed of sand for support.

robert_cheal
09-04-2008, 02:21 PM
Here is some more information

http://www.djgrp.com/djg_cnc_stylus_forming.pdf

robert_cheal
09-04-2008, 02:30 PM
Yet even more about the process.
http://www.djgrp.com/djg_engineering_overview.pdf