How would I print digital images on thermal plastic sheet approximately .080 thickness and 8×8 inches square. After sheet is printed, I would also need to be able to heat the sheet for molding and be able to press the sheet around a mold. Transfer paper does not provide the result i am looking for because once heated, the image becomes sticky from the heat. I heat the plastic to approximately 330 degrees before molding.
You could silkscreen w/ a suitable ink — just print onto some suitably transparent material, use the sun to expose a photo-emulsion screen, then print.
Alternately, use a CNC machine and an engraving bit.