Die cutting plastic

Can a windmill die cut a 20pt plastic card. Cut area is a 3 inch circle for a coaster. Are there risks, will it work, am I just nuts to think it can do it. Am I over thinking it and its not hard to do ? Advice please?? One way bus ticket to stupidville headed my way!!

Log in to reply   18 replies so far

With the often quoted impressional strength of the Heidelberg PLATEN 10 x 15, in mind, perhaps THE question should be is there Cutting Rule up to the job.?

We will check with our die makers. We also wondered if the Windmill would work or not. I hoped someone had done this before and has insight about the performance.

You likely can, but much depends on the grade of plastic. Scores and other features will be unending sources of frustration. For a single round, it will probably work. If you pack behind the die jacket, you will have to use metal, as the cutting pressure may press dents into any kind of resilient packing. For my experiences (die-cutting poly ethylene) an absolute PITA that I would avoid. YMMV.

Thanks for the feed back. I wanted to be sure I was a little nuts. It helps to hear it form those that know best

Would kinetic energy be involved….ie friction between plastic and cutting edge be sufficient to “melt” plastic to the steel?

In a word: no. The movement speeds that conventional letterpress equipment can move does not approach that level. Not to say there are not gummy plastics out there. Generally why you don’t see punched plastic problems much—everything is molded somehow.


Thank you all for the feed back. This is something we might just try - very carefully - .

Depends on the “plastic”. We offset on 20pt synthetic. Had enough room in the offcut recently and the new kid had prepress print his business card there thinking it would trim at the guillotine. I suppose the cutter operator was busy as he decided to put that scrap aside near my stone.

Having free time during a long run on the second windmill I locked up the round corner bc die. Ran the 9 x 3 inch sheet to guides…beautiful cut on the synthetic. Not sure how long the die would hold up. I cut about 100 pieces for the kid.

OK, it’s been years ago; May of 2005, I found the invoice. On a windmill - I ran a 30 point plastic card, holographic foil, then a diecut with round corners. 2,000 cards for $911. As I recall we had some scratching on the back of the material to deal with. Taping some paper over the jacket solved most of the scratching. Use an outside bevel die to keep the piece from crimping. Use hard packing under a standard jacket. We use 70# coated book.Our plastic supplier was Transilwrap; they sent a bad batch of plastic but replaced it. I would find someone else next time. I don’t think you can get in too much trouble—go for it! PS I miked the thickness at .029.

image: MDs.jpg


out side bevel with some “Breakers” around. Or, try “Long Center Bevel” rule with breakers around prob ev 90 degrees should work. Have the die board cut for ev 45 degrees in case you need more.

Thanks for the feed back. It does offer some interesting possibilities I never consider before. I will let you know what we end up doing. I enjoy doing the things other are not doing.

What are breakers? Are you referring to nicks to hold the piece in? I wouldn’t put any nicks in till it’s on the press, then I’d use a Dremel tool to minimize the number of nicks. You’ll have to go deeper than normal. You may not need any nicks at all.

Breakers likely another name for stripping rules. Cutting rule outside of the product area that make it easier to get to the finished part also can relieve pressure when diecutting thick stocks

Of course, thanks Mike. I’ve done that before. Didn’t know the official name.

if you’re doing a circle, breakers would look like cross hairs of a rifle scope, only, outside of the image. they specifically do as stated above. remove or add as needed, or not needed.

Breaker, stripper and chopper are all the same idea. Outside of product to relieve pressure and or ease stripping. Not to be confused with balancing rules that distribute pressure.
Chopper Knives - Steel rule in a die to cut up scrap in smaller pieces. (Also know as stripping knife)

Sure it’s not a problem.
Did some 7000 sheets job (on GT) with over 11 meters of cutting and creasing rules, and over 5 meters of hard rubber.

image: Big Die.jpg

Big Die.jpg