PDA

View Full Version : Punch & Die Help



CCWKen
01-12-2007, 09:42 PM
How would YOU go about making this shape for a punch and die set up?

http://img.photobucket.com/albums/0903/CCWKen/Projects/FuseTab.jpg

The material will be 101 copper about .030" thick. Just to give a little scale to the piece, the bottom tang is .500" wide. It will eventually be in a 2" diameter die format. I was thinking of doing it in a build up because of all the segments. Or could this be better done with a steel rule die? That would be easier to make.

Any thoughts?

EDMTech
01-12-2007, 10:26 PM
Wire EDM ;)

Or you could make the die in two peices, that's the old school way. Split it horizontally, grind in the two rectangular pockets on each side, put the die together, firm press fit into the die block. Give me a minute I will edit your pic to show you what I mean...

EDMTech
01-12-2007, 10:56 PM
http://i91.photobucket.com/albums/k281/PeteZ28/dieblock.jpg

Make a block (red outline) and split it in half (red dividing line). You can then hold each half of the block verticly in a grinding vise and grind in the halves of the boxes. Then just assemble the die.

Old school :cool:

Mcgyver
01-12-2007, 11:28 PM
Make a block (red outline) and split it in half (red dividing line). You can then hold each half of the block verticly in a grinding vise and grind in the halves of the boxes. Then just assemble the die.

Old school :cool:

back when the men were men. there'd have to be clearance angles involved as well and the press fit holes would have to ground after heat treating? I see why the the old school tool and die makers were held is such reverence. i end up on a lot of plant tours and see these multistage dies with 8 stations or ones at GM that would pretty much fill my living room or ones for die casting with mechanical cores that move in and then expand; humbling to the garage machinist.

J Tiers
01-13-2007, 01:22 AM
Do you need the sharp inside corners?

It makes a difference, because if the inside corners need to be sharp, you need a way of getting them sharp. That means getting a tool in there for the die half.

Splitting it is one way, and buildup of several pieces is another, since the buildup of straight pieces will definitely give your sharp corners.

I am no die expert, but I have now actually built a couple. I used buildup to get sharp inside corners. Easier than trying to work them out.

The real old-school would be to make it under a bit, and then have one or two "broach" parts, that you force in a few thou, then file off the burr, and repeat until you have the shape fully cut thru the straight portion of the die. The first broach part is a little under, if you do two, the second is the finisher.

Obviously before hardening.

DR
01-13-2007, 06:33 AM
Are you trying to make a hole in that shape, or blanking out a part of that shape?

How many holes/blanks? If only a few "nibble" it out by using a smaller rectangular off-the-shelf punch/die set.

If many parts have punch/die wire EDM'ed. Die would be done in pre-hardened blank, punch would be same pre-hard, but it would have to be pinned/bolted to softer shank. From my previous experience having punch/dies made my guess is $500 to $750 (that's cheap, IMO).

An experienced EDM shop will know the proper clearances for your material.

Another thought is to get the punching operation quoted from a fab shop with a CNC punching machine, they would nibble the part to shape. The parts would be done from sheet stock.

Or, have same fab shop quote the parts running them on a strip fed punch press with them making/owning the dies themselves.

2" diameter is not a "standard" die size, use 2.75", that fits Roper-Whitney and other's holders. Likewise use 1" shank. With those sizes it could be used in power presses with standard adaptors and R-W/Di-acro style hand presses.

CCWKen
01-13-2007, 07:37 PM
Thanks guys! Especially EDMTech--Brilliant! I'm going with the split die format. I don't really need the sharp corners. The drawing was just a quickie using rectangles. I was more concerned about general shape. A small radius on the corners will work. In fact, it's preferred for handling.

As far as out-sourcing, there's not enough volume to warrant that and too many to cut by hand. I've been doing that. :rolleyes: The die will be 2 1/8" not 2", my memory mistake. I can either use that or 2 3/4" dies. I use three sizes but I don't think I can get this in a 1 1/4" die.

.002" punch clearance should work, right?

J Tiers
01-14-2007, 02:06 AM
You wouldn't have to split it if you can do a radius.

One way is to spot all your inside corners through the cutting depth with a drill that will give your radius, or preferably a little under for finishing.

Then you can mill and drill out a lot of it and have very little finishing to do. If you don't split it, you avoid fitting, pinning, and fastening etc.

Copper is "wipey" if dead soft, but 0.002 is a small clearance.... even for 0.030 thick.

How much burr can you have?

Is the copper dead soft or as-rolled?