General Creasing/Scoring question...

[dagoof]

I've had a supplier crease some heavy stock for me on a Heidelberg Cylinder but the crease doesn't allow the board to stay folded at all, it wants to spring open which isn't much use. They used a 2 point matrix, but are blaming the stock (415mic), saying there's no solution - think they tried a double pass, but said it was too close to cracking.

Is this the case? Are there any alternatives I could suggest?
I don't know much about scoring, so would like to be armed with more info.

 

[Kees]

Hi, the scoreline should be in the graindirection of the paper, the RV should be 50 / 55% and the temp. 20 / 21 C. The channel should be 1,5 x paperthickness + thickness of the scoreline (stock 0,4 - scorline 0,7 - channeldepth 0,3 - channel = 1,5x0,4+0,7 = 1,3mm, optimum is 0,1 smaller so 1,2 mm). But it will alway's be a little "open", not perfectly flad / closed, if you want this you might slit the material instead of score.
Regards, Kees

 

[dagoof]

Thanks very much Kees, that's really helpful, I'll pass it on.

 

[Fatboysmart]

Maybe you can press them closed using your or their guillotine cutter. Our polar has a setting that only presses the beam down without cutting it. This way you can apply 5000 or more pounds of weight to the crease which would help them stay closed... sort of.

 

[dagoof]

Thanks Fatboy, but that's not really practical for my use - don't need them to stay 100% shut, only 80% or so.
Have passed on Kees' info, hopefully that will help.