Hi could anybody tell me how they deal with powder problems when laminating, is there any kind of suction removal system prior to the laminated layer being applied to the sheet that can be fitted to a laminating machine. regards john
Your real problem is that to much/wrong powder has been used in the first place. Dusting through a printing press is the only option i can think of
Hi John, I spent 7 long years running a wet-OPP laminating department and spent a good percentage of that time dusting spray powder off the printed sheets (SRA2 and SRA1) using a clean cotton rag. Too much spray is a common problem and gives you a nasty "star" type pattern or "silvering" randomly across your sheets - you can still get this problem even with thermal OPP lamination. Either grab a cotton duster or chew the b*lls off the printer who can't control his spray powder If the job has heavy solids then it's understandable that lots of spray may have been used but you may as well cancel your gym membership now coz you're in for a serious work-out with your left/right arm - you will have the arms of Mr. Universe by the time you're finished. Good luck!
This is an age old problem that doesn't have a favourable solution after the spray powder is applied. In my experience even dusting will not remove all the powder because much of it can get trapped in solid areas of ink and it is these areas that show up the "silvering" most. I worked at a carton printers in the seventies and the only way we could get round the problem was by installing UV curing lamps on the presses - then we could print without spray powder getting anywhere near the sheets to be laminated. Laminating then was by wet application of the adhesive to the film, drying the adhesive and then laminating to the sheets all in one process. Thermal lamination may give better results but eliminating the spray powder in the first place is the only sure way of getting rid of the "silvering". If you can't use some form of accelerated drying (IR or UV) you could try taking out very small lifts of your prints from the delivery (you may need an extended conveyer system at the end of your press) and racking them out to dry. Screen printers use a racking system that would be ideal. You could try asking around to see if you could buy or borrow one. I’m afraid I can’t be any more helpful.
JOHNYPRINT Spray powder seems to be a touchie subject with most operators, one they don't like to do maintaince to the spray units, and they don't like change. I have switched over many machines to c-350 from the usual c-230 and you only need half the amount or even less pending on the coverage. Now for board stock you can go to c-500 and you need very little. The next hurtal to get over in how are the sheets dropping in the delievery, most operators like to force the sheets down to the pile, no matter how much powder is used set-off still happens. When the operator is in control and the sheets floats down it requires less and when using c-350 large piles with very little spray, which is good for everyone in finishing. There is a flat beam light on the market to check how much powder is making it's way to the sheet, with it you can also check to make sure that it even across the sheet properly, you will need a long table and low light.
The only solution is dusting through printing press.The more ink units you use with pressure the better, and clean the powder from blankets after every 500-700 sheets.
