PALSUN Technical Guide

PALSUNTechnical ManualFigure 20: Pressure-Bubble Plug-Assist Vacuum FormingPressure Forming Air (When Used)Mold CavitySealAirVacuumA. The PALSUN sheet is heatedand sealed across the moldcavity.B. Air is introduced,blowing upward into anevenly stretched bubble.C. A plug shaped roughlyto the cavity contourpresses downward intothe bubble, forcing itinto the mold.D. When the plug reaches itslowest point, vacuum is drawnto pull the plastic against themold walls. Air can be ntroducedfrom above to aid forming.6) High air-pressure blows-up a heated sheet through a shaped aperture, resulting in Free Forming, a smooth,free-form bubble shape, without touching mold’s face. Both interior and exterior surfaces remain smooth andblemish-freeFigure 21: Free FormingExamples of free-form shapes that can be obtained with openings.7) Mechanical Forming:This method uses no molds, only mechanical means like bending, stretching or holding to form parts of relativelysimple design.c. Troubleshooting Tips for Thermoforming:Please consult the Faults & Remedies for Thermoforming Table (Appendix 3, page 42) at the end of this manual.33