Diecutting Coaster Stock

Fill in center of die try a couple of thicknesses of corrugated cardboard to support the sheet within the die

Use a side bevel rule, bevel side facing out. That should give you a cleaner cut. .918 3 point is OK, but 2 point would probably be my first choice. See side bevel here;
https://www.ameriken.com/products/steel-rule/steel-rule-cutting/
Good luck! -Bruce

I agree with the Side Bevel facing out. With a windmill, you may have to stay at .918. with my Kluge i would have ordered die at .937. I would get some very firm ruber and fil completely the inside.This is done by apply some white glue to the inside, and around the outside. then hit an impression against the foam rubber. then cut the extra around the outside, leaving about a 1/4” rim around the outside. pull the rest away.
i would have also added some small “Breakers” extending outward from the die. maybe 8 of them spaced evenly around. Don’t need to cut to the edge of the sheet, just make some cut to relieve pressure.

I agree with the Side Bevel facing out. With a windmill, you may have to stay at .918. with my Kluge i would have ordered die at .937. I would get some very firm ruber and fil completely the inside.This is done by apply some white glue to the inside, and around the outside. then hit an impression against the foam rubber. then cut the extra around the outside, leaving about a 1/4” rim around the outside. pull the rest away.
i would have also added some small “Breakers” extending outward from the die. maybe 8 of them spaced evenly around. Don’t need to cut to the edge of the sheet, just make some cut to relieve pressure.

I haven’t been able to apply full-face rubber on my windmill. It won’t cut through. I rely on my die maker to do it.

How many coasters you trying to cut per impression? Coaster stock can be rough work. Lot’s of power needed. i am in Milwaukee, Wis. I could cut these for you on a better press for this type of work.

Thank you for the advice, everyone!

Bppayne — Would you do 2pt rule even for very thick stock? Or would it make sense to stick with 3pt?

Ericm - Where do you buy the rubber you use? Just wondering what to look for.. I am printing just 2-up right now.

I buy precut rubber strips and my dies from Express Die in California (562) 903-1700. I use the strips for repairs and also straight perfing setup. I was wondering what type of paper and how thick this is. If this is blotter board was this the top of the die, it may just be a pressure issue or a die that was not flat in the lockup. Blotter paper is brittle and can crush, it does not work as easy as a cotton will. Do you also get a crush mark on the outside or waste part of paper.

Annie, your die maker should be able to supply you with a few different durometers of rubber in sheets or pieces big enough to engulf your complete image area.

ditto to ericm If the mark is a crush compression then softer rubber material to that area may fix you problem. Adding more rubber to the inner void and even outside may also help Best guess soft to the inside harder to the outside. Also try backing platen pressure to see where the problem starts. You want an even hit point into the sheet. You may be able to back off pressure but put fine packing under the die cutting plate and better balance the point of compression. It also never hurts to try slowing the speed down.

AnnieW, Re-knifing with side bevel is first choice solution. My concern is 3 point rule displaces more of the stock and may be part of the problem with the crimping you see. I’ve never had a problem with using 2 point rule on thick stock, that’s my experience anyway. Side bevel rule should help a lot, even with 3 point rule.
Regarding rubber; I honestly don’t think it matters if you use full face rubber or use strips of ejection rubber. But, that being said, I have always kept my options open. My opinion is the crimping is caused by the center bevel rule and not the rubber or lack of it.

Thanks again, everyone!! There’s been a slight delay in the project I was about to embark on, so I am not quite ready to pull the trigger on a new die just ye. But I will soon and will post the results!

Diemaker here. Reknife with 2 pt dbl long bevel this rule tapers about 3/16 of an inch from the cutting edge before the body becomes 2 pt thick. Looks like a lazer cut die. Your diemaker can insert .014” card stock or shim beside rule to fill the kerf void. Using side bevel rule may work and may not as often the stock delaminates during ejection.

I had a similar problem on 1.5mm beer carton.
I even had to completely redo the order! and this time I took a 1.4mm thick beer board from another manufacturer. At the same time, I did not change the cutting knife. The result on another cardboard is absolutely perfect!

@Neket, where are you located? Who are you ordering the beer board from, if you don’t mind sharing? :)

2AnnieW
I am in Russia and of course I buy cardboard from local companies. It’s called PANKADISK

https://www.doublev.ru/catalog/pivnoy_karton/pankadisk/