I am interested in forming some shallow rectangular bowls from 0.040" copper. Bowls would be about 1/2" deep and 6" square. I need a press of some sort to do this, one possibility would be a fly press but I don't know how big a press I'm going to need. Does anybody have a formula for the press force needed for forming this sort of thing. Note that I don't need to cut the copper, that will be done in a separate operation using a plasma torch, I just need to press them into a rectangular bowl shape. Thanks for any help you can give.
This isn't really a forming op, it's drawing and it's a bitch. GFL if you think this is going to be cheap. You'd be better off constructing these...unless you need thousands and they sell for a lot!
On Sep 17, 4:35 am, Steve Schlaifer wrote: Does anybody have a
for any help you can give.
I do not have a clue, but if I were doing this, I would put a pressure gage on a hydraulic jack and kludge up a way to use the jack to form the copper. That would give me the actual force needed. I always choose a measurement over a formula.
=========== You may want to consider urethane forming dies. see
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commercial presses, materials and operations
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Given the material and production volume you can cumshaw up an adequate manual hydraulic press using a bottle jack, short sections of channel iron and some all-thread.
With your low production quantities a hardwood form such as maple should be adequate. The only question is should the form be the male or female side of the die. Any of our readers have a suggestion? Any suggestions for the urethane pad such as sources and durometer? Anyone successfully cast a short run die [male or female] from the prototype?
Unka' George [George McDuffee] ============ Merchants have no country. The mere spot they stand on does not constitute so strong an attachment as that from which they draw their gains.
Thomas Jefferson (1743-1826), U.S. president. Letter, 17 March 1814.
Draw die construction is pretty simple. Making the thing work can be very tough, depending on your requirements.
What kind of rad do you want on your part? The smaller the rad, the tougher the draw. 1/2" would be simplest.
What about vertical walls? The closer to 90=BA you get, the more difficult.
Make sure to polish all your rads until you can see your face in them... Seriously. Start with 120g sand paper, and work your way down to at least 400, if not 600. Get rid of deep gouges left by the coarser paper.
As for your drawing force (pressure requires an area - you're interested in total force required), I can't recommend a minimum. More is always OK. Not enough is bad. You'll likely have a tougher time with a press based on a simply hydraulic jack. Drawing should be completed in one continuous stroke. Once the material stops moving, its hardness increases and it becomes more difficult to continue.
0=2E040" is not thin material by press tooling standards. You're probably looking at 50 tons or more to get anywhere. I can't even say that'll be enough.
How many parts do you need? Does it have to be beautiful, or can you tolerate wrinkles and thinning? Does the "floor" of the shell have to be really flat, or does it matter? Are you going to be building/ tweaking the tooling, or are you going to pay someone who knows what they're doing?
If you're pretty liberal about your requirements, you can probably hack together a functional tool. If you're picky and this is a sellable product, you're likely better to farm it out.
Actually, I misstated the requirements above, these are about 1/4" deep with a 1/4" radius curve.
There are no walls as such, the edge ends at the end of the curve.
Good advice, my mold maker friend said essentially the same thing.
That'll be more of a problem, 50 ton presses are pretty pricy.
Limited runs of a dozen or so at a time but hopefully lots of these over time.
No wrinkles or thinning, floor needs to be flat.
Hoped to do it myself with help from my friend(s).
Thaks for the advice, I can get these from a vendor but was hoping to start making them myself. They are a sellable product so they have to be pretty good quality.
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