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Printed plastic forming advice please

Posted on Mon, 12 Sep 2005 at 11:48



Hello,

We got our 6x4 ft semi-auto press and recently we ventured into Vacuum-thermoforming of printed Acrylics for Light boxes.
We face the problem of “image deforming” shifting of elements after forming.

1. Is this a problem faced by every ‘print-thermoformer’ ? No permanent precaution available ?
2. Is it practical to restrict heating outer areas(stretch areas) only, by individual control on the Ceramic elements, to avoid stretch on the printed, flat area?
3. Is any software available ?
4. Is any books available, which explains this particular problem in thermoforming ?
5. What are your expert suggestions as precautions:
A. on Plastic substrate,
B. Artwork,
C. Vacuumforming Machine etc.

We value your recommendations & suggestions, which are curcial for us.

Thanks for the time.

George

Location of Opportunity or Item

Comments

Anonymous says: maybe acrylics not so suitable for printed thermoforming.. why not try on polycarbonate (PC) ? posted on: Thu, 12/08/2005 - 1:16am
Anonymous says: George, Answers to your questions: #1 - Yes, all thermoformers have the problem you describe. #2 Impractical #3 Expensive autocad software and or computer generated modeling #4 I don't know of any right ...

George,

Answers to your questions:
#1 - Yes, all thermoformers have the problem you describe.
#2 Impractical
#3 Expensive autocad software and or computer generated modeling
#4 I don't know of any right off hand.
#5 A - For light tables acrylic is excellent, PC will yellow and PETG may
soften and shift even under fluorescent lighting
#5 B - Typically you would produce a 1/c grid - image can be ghosted back to about 30% - and then print.

Vacuum form the the printed grid. Pick four or five spots on the grid and then ensure the movement is staying the same. If you see the grid jumping around - the art will never be the same. The forming process must be constant - Heat etc must be controlled. The grid method is the best way to Q/C the forming process. Once you have consistancy, good grids, the art work is manually distorted based off the movement in the grid. It's a time consuming process, but I have found it to be the best. Vector or Raster art is okay, but Vector art is much easier to work with.

Once the art is distorted on the computer reprint the distorted art (ghosted back) with the grid on top. 1/C print again. Normally it will take two passes through this process to nail it.

#5C ?? I'm not to sure on this one.

posted on: Wed, 03/08/2006 - 5:23pm

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