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Punch dies.. is there a generic punch block?

snowshooze

Hot Rolled
Joined
Sep 15, 2010
Location
Anchorage, Alaska, USA
Hi guys, look, I am adventuring again.
So, I need to stamp out some parts that look like flowers, about 2 3/4" in diameter, and out of material sheet, about .015" thick.
For now, I am milling the parts.
But, I want to punch them. It is pure, common sense.
Does anybody sell blank stamping blocks that you could direct me to, or do I really gotta start from scratch???
Again, my many thanks.
Mark
 
"Blank stmping blocks" is not a description.....

1) Do you have a press that takes sized punches? If so, see if there are punch/die blanks for it, as the punches probably have extracting slots etc that are specific to it.

2) Do you have a generic press? Then you may want a set consisting of top and bottom plates with guide posts. Then you can mount your own. Not cheap, no clue what your qty or costs are.

3) If none of the above, how do you plan to do the stamping?
 
I stamped some thin annealed brass sheet using a cast iron male punch and blocks of lead. I poured a new lead block for each part I stamped, using a 12 ton hydraulic press. Mind you, I was only doing the forming this way. I had to use a silversmith's snip to cut the edges of the sheet after forming. It worked fine for the small job I was doing.

Larry
 
Yea, I'm thinking you're going to require a die shoe set with custom tooling, both the punch & die.
I don't see a way to hold the punch in an ironworker type of machine, what with the punch OD being about 2-3/4". Most retainer nuts are too small for that size punch.
 
Yea, I'm thinking you're going to require a die shoe set with custom tooling, both the punch & die.
I don't see a way to hold the punch in an ironworker type of machine, what with the punch OD being about 2-3/4". Most retainer nuts are too small for that size punch.

Exactly. The best way is to have the punch and die wire cut. You can calculate the required tonnage for that easily. Then you will need a stripper plate to hold the strip down while you punch it and strip off the skeleton. You will need about 10-20% additional tonnage for the stripper. That will then tell you the required press tonnage.

Best you work with someone that understands press work dies.

Tom
 
If you're only punching 0.015" material, you might be able to use a jeweler's technique, where you make one narrow cut in a sheet of tool steel to form both the male punch and female die. Leave a tab attached between the two, bend the male punch up somewhat, slip the material in the narrow V thus formed, and press the sandwich. The tab keeps the punch and die aligned. Obviously, only good for quite thin and reasonably soft/weak work material.
 
There aren't really any blank punch/die sets in the diameter you want that I know of. This is likely too big for iron worker tooling. Unless you're going to make a lot of them (think thousands) or they're going to be high priced finished pieces making a die set, even a small one, will likely be prohibitively expensive unless the shapes are very basic geometry. If the majority of your profiles will be round then it's possible to create everything (punch/die/stripper) for lower cost but it also depends upon whether you need to heat treat (type of material) grind after HT (likely due to small cutting clearance), allowable burr, type of die (progressive/compound/coining/etc.) that the piece part requires. It's also possible to have a hardened punch and soft die section that gets "peened" in and then shaved by the punch for proper clearance but that's somewhat of a skill to do this and not for a first time method. If the part profile is NOT basic geometry then WEDM is probably your best bet and that drives the cost up. You also haven't said whether you want the entire piece blanked or it's a multi-piece assembly (weldment/soldered) as that affects your die selection and cost. Stamping dies are a good choice for a run of thousands, not so good when it's only a few hundred of a one-time run. Photo of part being considered can offer more suggestions from the collective.
 
Yes, the thin material means a very small clearance, so not a simple sloppy die.

If of brass or suchlike, maybe the peened and shaved soft die would work decently.

If you can mill the parts as you mentioned, (probably in a stack) then you could stack them and have the stacks wire EDM'd, which might suit your quantity, and spreads the cost over the entire stack of parts. Each inch of stack is 66 parts.
 
That's pretty easy. We've been selling oversize punches to metal fabricating customers for 40 years. They have a 1" shank with an angle set screw to hold them in because they are too large to use the coupling nut. We call them single station tooling. Probably have a dozen laying around here over 2-3/4". All you have to do is grind off the little aiming point and you have a "blank".
 








 
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