Vacuum forming PETG

[lenbh]

Hi, everyone!

I'm hoping that someone can shed a bit of light on a problem that we're having. We're vacuum forming clear 1/4" PETG on a mold made from Prolab 65 (a medium density PU material). We're getting excellent results, except that we're seeing "fogging" in the areas where the draw is greater - anything over 1/2 deep draw will begin to fog, and we have some surfaces drawing down about 1.25 inches over a near-vertical surface (we're not seeing any big problem with thinning of the material).

Any suggestions how to eliminate, or at least reduce, this? We've tried varying the temperature and cycle time, but no difference.

Thanks in advance!
Len

 

[coatingengineer]

Hi,

Are you certain there isn't excess, localized heat?

Assuming this isn't a surface finish issue, your description sure sounds a lot like out-gassing.





William Gunnar

http://www.IndustrialCoatingsWorld.com