Good Impression vs Poor Stretching of Card Stocks

[dwanehollands]

Hi guys,

Just been experimenting with some thicker boards on press today. Thicker for us, probably pretty lame for packaging printers. lol.

The thickness of the boards we were printing were 360gsm Rapier Artboard from Spicers Papers and 420gsm version. They're like 0.35mm thick and 0.41mm thick respectively.

What we've noticed was, it was difficult to get good impression (eliminating patchiness) while avoiding crazy stretching issues on the tail end of the sheet. (like close to 0.6-0.7mm) We backed off the impression and it went back into perfect fit, but it gets slightly patchy. Not shockingly noticeable, but a printer would pick it up.

Same deal for both stocks. Literally 0.1-0.2 tolerance on our impression settings between good impression and poor stretching. The blankets are very new. Only changed about 1-2 weeks ago and printed other work with no issues. In fact unit blanket was new as of yesterday (Ripped a 15mm channel out of it, down to the packing when a piece of the aluminum guard broke off and went through the machine. Praise God there was no cylinder damage!!!!!)

Anyways, should we look at different blankets or packing to get around this? Any ideas?

Cheers!

 

[Paultheprinter]

Ive seen this quite a lot lately as ive been running a roland 700 on manilla and card, we run index cards which you get on medical folders and when you lay the film trace on the job there is sometimes a distance of up to 1mm lateral and circumferential. My feelings were to run a harder blanket to avoid the squeeze at the impression nip and avoid excesssive stretching. Never going to get a chance to see if this works as im only filling in for an ill operator.

Paul