Need Help UV Ink not adhering to Coroplast signs. (Peeling Ink, Sun Exposure)

[MachServTech]

1. Check your coroplast for the buildup of plasticizers. You can use a Dyne kit or you can wipe with alcohol on one side to compare performance.
2. Make sure the Lamps are in good shape. Have a calibrated light puck to see how many Jules you are throwing down. Be consistent. (also running too fast is bad. If the ink isn't getting enough UV in time you have to slow down)
3. Check the inks. Date of expiration matters. Are you using the best formulation? If you primarily print coro you should have an ink optimized for this.
4. Don't Sweat. If your coro gets hot it sweats plasticizers.
The goal is to get the UV to bite into the coroplast slightly. The reasons above are why you may not get good adhesion. Pay attention to your scratch tests and weather test some samples outside under different printing conditions. Have a baseline for your process and stick to it.

 

[parrott]

a lot of valid info above, Dyne levels, UV lamps settings, and deterioration mostly on the old style Merc vapor Lamps, and too much ink., but the biggest real issue is just inks that don't stick. The good News is we have an inkset that sticks absolutely, the bad thing (maybe/maybe not) is its formulated for our Printers.

https://www.dropbox.com/s/2h499tlqmz76yer/Scratch test.wmv?dl=0

I spy some of my samples from when we were looking at the Digitech! Great printer with the strongest ink I have seen. If it doesn’t stick, you can’t send it out the door. My days of worrying are over!

 

[Commando]

Corrugated plastic is TEMPORARY signage. 6 months to a year on that cheap crap is good, IMO.