Curling after application of UV varnish on a UV coater

[falvarado]

Good Morning everyone,
I would like to ask people that have experience with UV coating.
I have a Chinese UV coater, and when I coat UV varnish on heavy weight paper I have no problems, but when I go under 216 gram paper, with lighter weight paper, it will curl upward after a few days. I have tried putting less amount of UV varnish, slower speed, grain direction change, more and less intensity of UV lamps, but it all has been unsuccesfully, paper will curl up after a few days.
If anyone could give me suggestions I would appreciate it very much.
Best Regards,
Francisco

 

[M@CK]

What brand coater is it ?

 

[falvarado]

iT IS A HEASN UV-650A, MADE IN CHINA

 

[falvarado]

It is a heasn uv-650a

 

[old guy]

assuming you are flood coating with a roller type machine. i dont see where the type of machine would cause curling. ask your coating rep for some samples of various coatings to see if a different blend works better

 

[denisbunn]

Hi Francisco

What wavelength are your u/v lamps working at? A standard uv curing lamp is mercury and has a wavelength of 365nm . A gallium doped mercury lamp has a wavelength of 425nm. Are your coatings being cured completely?

For more information please contact me, email [email protected]

Regards Denis.