Vacuum Forming

Lormac Plastics has over 40 years of experience in vacuum forming of quality custom parts. Our largest, fully automated, machine can form 4 foot by 8 foot blanks of .06 to 1/2 inch thick materials.

Vacuum forming offers several processing advantages over other forming processes. Low vacuum forming pressures are used thus enabling comparatively low cost tooling.

Since the vacuum forming process uses low pressures, the molds can be made of inexpensive materials and mold fabrication time can be reasonably short. The vacuum forming process is perfect for prototyping production parts and for small and medium sized production runs.

Thermo Vacuum Forming Process:

Clamping
The clamp frame ensures the plastic sheet is held firmly in place during the vacuum forming process.

Heating
Radiant heaters are used to heat the sheet which has been positioned over the aperture of the vacuum forming machine. Thicker sheets may require both surfaces be be heated by moving heaters into position both above and below the sheet.

Pre-stretch
Is used to achieve "even" wall thickness. Air is introduced to blow a small "bubble" and the mold is then raised into the pre-stretched sheet.

Vacuum Forming
A vacuum is applied, the sheet is drawn into tight contact with the mold and the mold detail is picked up.

Plug Assist
Where a deep draw is required, a top "plug" may be used to push material into the mold during the vacuum forming process retaining even wall thickness.

Cooling and Release
The material is allowed to cool. The cooling process may be shortened with blown air and the molding is then released from the mold by introducing air pressure.

Finishing
After the part is vacuum formed, secondary services are performed, including: trimming, cutting, drilling, assembling, polishing, painting, and screening.