Punch and die fixturing--best practices

[Borealis]

I've been using a punch press to punch out small discs (~0.25" dia.) out of 0.035"-thick 260 brass. Because they're round, the angular alignment of the punch and die hasn't mattered. Now, though, I need to make some parts about the same size, but with some features where the alignment is critical. Books on die design abound but I see very little information about designing holding fixtures for die sets that incorporate features for adjusting the positional and angular alignment. Can anybody here point to books or other resources that discuss best practices for designing die holders?

 

[boslab]

The die fits a bolster, a big recessed bolster can be used.
Lower the punch into the die, shim if needed ( sellotape is handy) then pour cerromatrix round the die.
Problem solved, cerro will hold it, I’ve done that on a 200 ton press, it works, cerromatrix make a bolster alloy.
Damn sight easier than wiggling the die round and trying to clamp it.
Mark

 

[RC Mech]

I don’t understand the issue here. Your dies are on die shoes held positionally with guide pins and bushings.

Does the press have worn guides?

 

[Borealis]

I don’t understand the issue here. Your dies are on die shoes held positionally with guide pins and bushings.

Does the press have worn guides?

I'm asking about best practices for designing fixtures mounted to the die shoes that
1. have adjustments for positional and angular alignment of the die, and
2. clamp the punch and die in place.

 

[RJT]

Anything adjustable can come out of adjustment. Punches fit in punch holders doweled and screwed to the top die shoe. Dies are doweled and screwed to the bottom shoe. Nothing is adjustable, it's made accurately to start with. Get with a good die designer.

 

[RC Mech]

I'm asking about best practices for designing fixtures mounted to the die shoes that
1. have adjustments for positional and angular alignment of the die, and
2. clamp the punch and die in place.

Nothing exists like this. Purchase a quality die shoe set and build or have the die built on top of that. These things are not built to move for a reason.

 

[Borealis]

Nothing exists like this. Purchase a quality die shoe set and build or have the die built on top of that. These things are not built to move for a reason.

Fair enough, that explains why I can't find examples of adjustable holders. Glad I never got rid of the #3 jig grinder.

 

[???]

I've been using a punch press to punch out small discs (~0.25" dia.) out of 0.035"-thick 260 brass. Because they're round, the angular alignment of the punch and die hasn't mattered. Now, though, I need to make some parts about the same size, but with some features where the alignment is critical. Books on die design abound but I see very little information about designing holding fixtures for die sets that incorporate features for adjusting the positional and angular alignment. Can anybody here point to books or other resources that discuss best practices for designing die holders?

Your supposition that angular alignment doesn't matter is incorrect. If the angular alignment is out the punch and die will clash on deep entry with small material clearances.

Die sets were introduced to aid in press setup and die alignment. Prior to die sets punches and dies with their backing plates were fastened directly to the plattens. Clearances were set with light or shims, this was obviously time consuming and prone to problems with press wear. Angular alignment was never adjustable.

As said by others purchase a good quality die set. Material thickness and speed will determine pillar and bush type. Don't try to compensate for press slop with a precision die set.