Topic: [ non-lisp ] Rotary die distortion equation

[James Cannon]

well on a 5"%%c roller, you have ~15.7" circumference, meaning that your 'punch' on the roll will hit the 'part/sheet' every 15.7" o.c. linearly along the part/sheet.

So the spacing between sheets (if there's no automatic adjustment that starts the sheet at a certain point in the rolls spin) and the spacing of parts ON the sheet.

Unless I'm just way off or not thinking of something else that affects it or SEANT was talking about something else..

[Strucmad]

Good points..

thinking out loud (can you hear the gears)
so the pattern is on the die, and it is rotating, the sheet is flat.....slaps forehead 'doh'
man I was way off with my mental picture of this one, I had it all ass about

what josh said sounds fair..

[T.Willey]

What he says would make sense if it was sheets, but it is one continuous roll, so what doesn't matter where it hits really.  Only the first or last would need to be trimmed down, so that they are the correct sizes.

[James Cannon]

What he says would make sense if it was sheets, but it is one continuous roll, so what doesn't matter where it hits really.  Only the first or last would need to be trimmed down, so that they are the correct sizes.

oh, ha... yea that pretty much solves that issue.  Forgot about that.  I come from a manufacturing background centered around smaller runs that didn't facilitate such bulk quantities.

I really have trouble wrapping my head around how your die could be off on one spin, then correct on the next.

[T.Willey]

What he says would make sense if it was sheets, but it is one continuous roll, so what doesn't matter where it hits really.  Only the first or last would need to be trimmed down, so that they are the correct sizes.

oh, ha... yea that pretty much solves that issue.  Forgot about that.  I come from a manufacturing background centered around smaller runs that didn't facilitate such bulk quantities.

I really have trouble wrapping my head around how your die could be off on one spin, then correct on the next.

That there is the question.

[SEANT]

I was picturing everything on one roller, as in example drawing with 5.5 dia. roller, but suppose that isn’t necessarily the case.  And even if there were multiple rollers, it would be odd that one could slip but then catch back up some revolutions later.

[SEANT]

Unless – with multiple rollers – a loose timing belt and oscillating tensioner.

[T.Willey]

One roller with the pattern repeating as much as possible on that roller, at least that is my understanding of it right now.  I'll check out the dwg Seant when I get a minute.

[CAB]

Man I'd love to see a picture of this machine, or is that top secret?

[T.Willey]

Man I'd love to see a picture of this machine, or is that top secret?

That is a problem, as the machine is so old, and most of the drawings for the machine don't exist as we would like them to be.  Lets just say it is a machine that makes drug patches.  It is pretty big, and pretty complicated.

[Spike Wilbury]

Alan,

I am not familiar with this stuff, don't know but maybe if you do a search on google images for "rotary die cutting machines"

[CAB]

Thanks Luis. Looking through some of the links that I turned up I see many types &
many applications. Really cool stuff. When I was a plumbing contractor I toured the
Price Pfister faucet factory in California and the State Water Heater factory in Tennessee.
I found that very fascinating. Remarkable how things are made.