Acrylic and Cardstock material will not lay flat. Need help!

[wiplash859]

Problem 1: We have applied graphics to the back of 5 24x36" cast acrylic sheets using a hot laminate process. After application the acrylic has begun to curve. Our attempts to flatten the pieces will work but only temporarily. Any suggestions?

Problem 2: Similar issue but with card stock material that we are using to print outdoor durable political posters. The material is laying on palettes that are completely flat but over time the material is becoming wavy to the point it will not print on our flatbed printer without causing head strikes.

It can be very cold in our shop sometimes dropping to the 50's. We've tried a few things to flatten these materials but nothing seems to help.

Any insight on how to get this stuff flat? Thanks!

 

[wiplash859]

Okay I have to come clean on this one. By "hot laminate process" what I really meant was we directed a heat gun at it while laminating (we have a cold mount pressure sensitive laminator). For the record I did not support this decision but the boss really wanted to get the job out. Now to get it to lay flat again...

 

[wiplash859]

Just regular laminate. It was a recommendation by our vendor to eliminate small bubbles in between the acrylic and the print. It worked except now we have curved material.

 

[J Hill Designs]

Im guessing the heat allowed the laminate to stretch while being laminated, now its cooling and shrinking

 

[ChicagoGraphics]

Sounds like you heated the acrylic to much, now it has a bend in it. See what happends when you try to cut corners.

 

[artbot]

if it's curving on the image side, the image has shrunk and is pulling that side to a curve. the only thing i would try is to put them in a heat press, low heat and then with they are coming out hot, sandwich them between two pieces of malemine board to fast cool them.

 

[animenick65]

Have you tried taping down the edges of the card stock so that it lays flat? That's what we do on our flatbed.

 

[edgette]

How thick is the acrylic? I think the heat warped the acrylic. You can try reheating the sheet where the bend is and applying some weight to hold it back down. When it cools it may be flat again.

 

[2B]

Just regular laminate. It was a recommendation by our vendor to eliminate small bubbles in between the acrylic and the print. It worked except now we have curved material.

What type of graphics?
regular laminate?

sounds like two types of calendared materials and done while hot so as cooled they went back to normal. how many passes on the graphics, ink saturation could be an issue

 

[tsgstl]

Acrylic expands and warps as it's heated. Anyone that has stripped vinyl off of a box face with a heat gun definitely knows this. But whichever way it's bowing will tell you which material is pulling harder. It's just like a thermometer. Unless you keep those sheets at the temperature it got to from the heat gun it will never be flat. Use thicker acrylic? Maybe try another laminate?

 

[Sign Eagle]

Card stock, like foamboard, will warp if vinyl is applied to one side. The paper on the non vinyl side will absorb moisture from the air and cause that side to expand a little causing a curl rather quickly in high humidity.

 

[BPI Color]

Had a supplier tell us the same thing. We have an all-purpose laminator with heatable rollers. Heating the adhesive did NOT accomplish the goal. I'd say you need a better optically clear adhesive. But, you also need to manage your work area. 50 degrees is probably too cool for most adhesives and laminates. Check the specs on your materials.