Using powder & UV lamps?

[Freeman A.Gain]

I'm looking for some answers about using anti-offset powder with delivery UV lamps. I used to run a KBA 105 with a Grafix system, which allowed me to use the powder with the lamps operating. Now I'm running a ManRoland which doesn't? Almost the same Grafix system, but it's ManR that says it shouldn't be done...too combustible. Are there non-combutible powders available? The ManR factory told us that we can do it, but we'll have to sign a "Responsibility waiver". WTF

 

[Cornishpastythighs]

Please forgive my ignorance, why do you have the need to use offset spray powder with UV.
Thanks

 

[Freeman A.Gain]

There are a couple of reasons why I would like to use powder. Firstly, we use a hybrid UV ink, which normally cures well enough for most jobs, but sometimes on the jobs with rich blacks on certain stocks, powder would help dry. Secondly, when we run heavy text and use UV gloss coating, powder would also help the job from sticking together, or the 'glass plate effect'. Lastly, on ocassion, we do a "special effect" varnish & coating combination, which also needs a bit of air inbetween sheets, to cure without bricking up.
Hope that clears it up.

 

[Servicetech]

Spray powder is just finely ground corn starch and is flammable, I have not seen any other form of spray powder. I have seen the aftermath of a few delivery fires where excess spray powder caught fire under/around a dryer. This was clearly due to lack of cleanliness and can be easily avoided by regularly removing excess spray powder.

A build-up of excess spray powder has a potential to catch fire under most any dryer system (IR or UV).

 

[Freeman A.Gain]

It is funny you would say that Servicetech, it seems to be such a real catch-22 with powder. ManR tell me that powder is explosive with UV lamp, but ok with IR. I get that, because UV lamps are much hotter, BUT... I know of another company in town that has ManR presses, which are UV, and they use powder. One of their pressman now work with us!!!! I also used to run a KBA that used the exact same Grafix UV & powder system!
WTF!!!

 

[janezl]

Spray can be enabled with SW upgrade. Man Roland will charge for it. Prior to order, you will get from Man Roland statement to be signed, that you will use powder spray with caution and up to (do not know exactly) 20% powder volume. Of course responsability if something goes wrong - up to you.
We did this procedure at my previous company for R705

Janez

 

[jonprintz]

Freeman,
When I read your description of why you want to add powder to the job it makes me think that you are not curing adequately. I'm sure that you have already examined the reflector condition and lamp life in your UV system but those are the first things I would check if I wasn't getting adequate cure on my sheets...especially with a gloss coating. Also, I would slow the press speed down to give more dwell time for the sheet underneath the lamps.

I cannot picture the gloss coating or textured coating not curing and bricking up. I've never seen that happen unless the lamps were not fully on. I would think that adding powder to this situation would be counterproductive to the "special effect" that you are creating.

High density rich blacks can be challenging. We have run certain jobs another slow pass through the press again with only the lamps on be certain there would be no problems with the job.

This doesn't address your question though. It sounds as if Man Roland got burned on this and is now being overly careful. Good luck with your situation.

Jonathan