Video of hydraulic forming copper piece

[Gene_Olson]

Here is a 3.5 meg video on Lee Marshall's site.

http://www.bonnydoonengineering.com/...ugingmovie.htm

It shows using a hydraulic ram to form the inside of a shape over a ureathane pad.

I'm thinking a lever arm on a kick pedal might work just as well.

G.

[wtowns01]

Gene, when I first saw the video I thought they were using some kind of power hammer. The way they use the press is too much open and closing of the valve. Looks tiring just watching. The whole set up looks kind of slow to me, but I guess if you have somebody operating the press while you hold the part it might not take too long. Of course though if you are using the deep draw method to make the vessel first then it might be worth it.

[Gene_Olson]

yeah, at 5 seconds per hit, that would be Sooooo boring.

and like I said, since they were working into a urethane pad like that, a kick tool on a lever would work just as well. There is no alignment issue.

being able to deep draw the initial shape would be a plus though.

I just did this little shape out of a pipe.

The belllied out part was done mainly with a rubber hammer over a stake.

instead of pushing the forming stake into the rubber, I pushed the rubber into the stake.

G.

[Doug98105]

Phil's video is interesting. Since I saw it the first time I've wanted to try the technique.

Here's a picture of a related method, except in this process a rigid bottom die is used instead of the urethane. This picture is from NASA, they formed 30' diameter Saturn rocket bulkheads out of 1/4" plate this way in a large hydraulic press.



Looks simple, draw a grid on the panel with closer spacing where the curvature is greater and start pressing. For sharper curvatures they use dies like shown in the lower left corner.

This method could be used in an arbor press or a shop type hydraulic press where the parts are too large for an arbor press.

Doug

[Gene_Olson]

Lee Marshall sells hard steel dies like those illustrated in sets.
the male dies are either 3 or 4 inches in dia and the mounting post is 1" so they could fit nicely in somebodies standardized lower anvil dolly block holders.

He suggests that one line the dies up with a couple pieces of double stick tape on the bottom of the female one to keep it from shifting.

G.