Does Gloss UV always give Texture / Grain?

[saifu7]

Hi,
i have one offline UV coating system recently bought from abroad. the UV Coating machine has a EPDM 50 rolller and has Chromed Roller (which coat to the EPDM50 roller). the EPDM RUBBER ROLLER actually does coat to paper. i get texture / grain when i use gloss UV. i want UV to look like very smooth and no texture like gloss film lamination. does any one has any idea how to kill the grain / texture while doing UV coating?

 

[TheProcessIStheproduct]

on a roll coater if you run more pressure it usually gets ride of the texture, you may be putting too much thickness down. You could also pull that roller out and get it recovered, some of the oversea's rollers are not ground very smooth and will swell up on the edges very quickly, someone like bottcher or diamond can re-cover it for cheap...

 

[saifu7]

Thanks for your tips. I am in fact using Bottcher roller (get rid off the roller came with the machine). i have used max pressure. it was better than before but still not smooth. do you think a stainless still roller can help to ink in to the EPDM roller? Also can i use IPA on the UV varnish??

 

[bhm8hwcm]

I assume you have tried slowing the machine down to let the UV flow out a bit prior to curing. As well I find the quality of paper can make a difference for the overall quality of lay down as well.

 

[Albnn011]

The actual Coating plays a roll as well. Some Coatings don't have the proper Flow Additives to work with these short dwell time machines. Also, try heating your coating, that activates the flow additives the coating does have. Usually 80-85°F is good for coating temps. We can provide you with quality coatings that are made for these types of roller coaters. visit us at AL's CO UV

 

[kansasquaker]

Two thoughts:

1. If you're running stock that you've printed offset, you my need to dust the sheets first. The spray powder often causes a texture. It also helps if you an AQ coat the sheet first. We generally run all UV jobs with AQ and low powder to avoid this issue.

2. If your machine has IR bulbs, try turning up the temp. The heat helps the coating spread and smooth out.

Good luck.

 

[Cornishpastythighs]

Heat the coating, slow machine down for max flow out, check coating viscosity and use a hard smooth polymer/cyrel plate not a rubber blanket to print the coating. I'm not familiar with offline coaters so dont know whether or not you even use a plate, if you do make it a Polymer one you will be pleased with the results

 

[TheProcessIStheproduct]

I doubt he is using a plate, sounds like a three roller nip system, Amalgamated has a high reactive coating that works well for the short systems that do not have IR heat, high wattage, or long conveyors for flow out...

 

[KPetrochko]

We had this problem when we first began offline UV coating, as we were trying to get more sheets out per hour than realistic. Roller speeds slowed down to 30% (ours is a FMA 3 roller design) and slower belt speed for 'flow-out' have given us the glassy look that we wanted. Promised speeds are not there, but the quality is.

 

[MalcolmBliss]

We've also had this problem in the past on our TEC Lighting system. I switched over from the TEC coating to the Anchor equivalent because we found the TEC coating to be quite thick and therefore, to me, would result on a grainy type application. However that is just a theory. We are also coating things coming off offset presses and press powder makes a stipple effect in the coating. If there was a way to maybe have a solution for everything, i'd tell you. I'm still learning this machine and quite frankly, imo, our aqueous coater on our 528 Komori does a much better job. We only use the UV for digital stuff mostly.

Have you tried running the sheets through to warm them up and then back through again to see what happens? It may smooth things out.