Been building progressive stamping dies for 25 years. The company I work for has a lot of older dies where the details, both upper and lower, are bolted in from the bottom/top side of the die set. Meaning you cannot remove a detail while in the press. Has anyone ever seen this before and have a good reason why a die would be built this way?
Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
Largest Manufacturing Technology Community on the Web
Stay Connected:
ATTN. All old school die builders (or any die builder)
- Thread starter moto367
- Start date
- Replies 6
- Views 1,734
Hobby Shop
Stainless
- Joined
- Mar 20, 2014
- Location
- Michigan
Slivers, grit and general contamination on the strip. Its been a while but I’ve built them like that on aluminum and SS dies before. Die changes are so fast now a days it makes more sense to dieset out of it and fix it on the floor.
Mike1974
Diamond
- Joined
- Nov 5, 2014
- Location
- Tampa area
Well if they were built "by hand" (not all cnc work, including shoes), it is much easier to align punches having access to the bolts from the top of the die set vs trying to align a punch and then get a wrench inside the dies set.
AD Design
Stainless
- Joined
- Jun 27, 2012
- Location
- Tennessee USA
I've seen/built/repaired more dies that were back mounted than face mounted. This is only my limited experience but it was with several stamping houses. Smaller issues like cam adjustment, form galling, and some forming operations can/are face mounted for removal/adjustment while in the press if the die was well designed. But for major problems (like chipping/fracturing of the CE, doubling, slug-up, etc.) a repair while in the press it may not be a good idea to tie up the press while a time consuming repair is effected. Sometimes it's better to just yank the die set and pop a different job in or get the back up set off the shelf if it's a long runner. Some places I've worked had two die sets for the same job for obvious reasons. Some places also insisted on back mounting to eliminate the possibility of a SHCS vibrating loose and dropping into the operation. The potential for catastrophic die failure wasn't worth the "convenience" factor. Design precautions were always taken with face mounted components, particularly in the upper shoe. As for perforators, that's a matter of preference. Some like/prefer the ball-lock perfs and some don't. They have proved to be convenient for me sometimes but I've also had difficulty removing them too. The closer the fit the more difficult they can be to remove but that's just my opinion. I've never seen a face mounted die with transfer pins/plates or spring strippers that were face mounted, not sure I see a reason to either. I guess it's more about what you're familiar with. Repair has a point to the convenience of face mounting. Building the die I'd prefer a back mount. If it's a high speed press like a Bruderer then I wouldn't want to risk a face mounted ANYTHING as you'll never stop it in time to avoid damaging the entire die and/or press. This is all just my opinion and should not be considered anything more than just an opinion.
Great explanation and reasons why. Like you said, it's what you're used to. Did you face mount the lower details or were they mounted from the bottom side of the shoe (against the bolster)? I can see where mounting and aligning the details would be much easier. Thanks!
AD Design
Stainless
- Joined
- Jun 27, 2012
- Location
- Tennessee USA
Most dies (bottom and top) were mounted on large parallels to make a common pass-through height for all the other dies that ran in a given press. This can sometimes also be useful for locating the die set in a "quick change" sort of set up to help pass through alignment of coil stock by using horizontal cut-outs in the parallels with alignment pins in the bolster. Dies that use transfer pins/plates and spring stripper can benefit from upper parallels in a perimeter arrangement. Lower shoe parallels also allowed for options in slug removal after exiting the die where flat on the bolster plate doesn't. I do know of one place (in Athens) where they machined enough holes/passages in the bolster plate that it warped. I would not advise following their idiotic example of poor die design. I sometimes saw components face mounted in the lower shoe, especially if trouble was anticipated in one station. If that's not the case then provisions like jacking screws, half side grind, and a decent slip fit on the dowels is required or it ain't coming out when oil does a hydro-lock on the section. I don't really see much advantage to face mount lower shoe because if something gets scragged on a cutting edge in the lower there's a good chance the upper punch is bad too so the whole die set needs to be pulled anyway. Then again, I'm willing to learn something if somebody wants to jump in here. I certainly don't want to diminish the experience/preference of those that like face mounting (no not that kind...) on prog dies. I'm just accustomed to back mounting with selective applications for face mounting. This does not apply to in-die sensors, that's another topic for discussion sometime. All of this is merely my opinion so take what is useful. Ganbatte.
Last edited:
Green Machine
Aluminum
- Joined
- Mar 8, 2005
- Location
- Southwestern Ontario, Canada
Back mounting is old school. Much easier to snug up punch holder when you need to knock them around for die alignment before dwelling them to shoe. I always hated having to reach into a die to tighten the punch holders when doing line up. One trick we used was a piece of broken off Allen wrench, with a small ratcheting wrench of appropriate size to drive the hex. But now most dies I have designed, customers would not even consider back mounted details. All details need to be press accessible and built to CAD. As well as adjustment on forms accessible with no disassembly. Not a big deal if you chip an edge, just grind it out and shim up if not too bad, or grab another and throw it in. Upper dies have either drop strippers, that can be left on bottom in the press, or Windows in stripper that allow pulling either the punch or whole holder thru the stripper.
Similar threads
