About spray powder

[gordo]

Do you use spray powder when running Heidelberg HUV ink? I couldn't find any info on Heidi's websites.

 

[Magnus59]

Do you use spray powder when running Heidelberg HUV ink? I couldn't find any info on Heidi's websites.

I can't speak specifically for HUV, but I commissioned a Speedmaster 102-6PL way back in 1988 to which we retrofitted UV lamps.
We didn't use any spray powder on this press. At times we still had sheets sticking together in the delivery, sometimes to the point they were a solid brick, however this has nothing to do with setoff, it is entirely dependent on the temperature in the stack. You need to ensure there is sufficient cooling of the sheets prior to them landing in the delivery, and on occasion you may also need to deliver in smaller than usual stacks and fan the sheets to allow air through the stack for cooling.
Even when the sheets have stuck together, they can usually be separated without affecting the print.
I also commissioned a Ryobi/Presstek DI UV press in 2006, this was also run with no spray powder.

 

[turbotom1052]

My one and only UV experience was years ago when UV curing on a sheetfed press was in its infancy. What I recall about that experience was that as long as your rich black process builds are set with good UCR curves you could make full stacks in the delivery, with ZERO bricking or setoff issues. The biggest problem we encountered was when plates were supplied by print brokers from outside sources.