The sheet, or "film" when referring to thinner gauges and certain material types, is heated in an oven to a high-enough temperature that permits it to be stretched into or onto a mold and cooled to a finished shape.
[1] Thin-gauge thermoforming is primarily the manufacture of disposable cups, containers, lids, trays, blisters, clamshells, and other products for the food, medical, and general retail industries.
A stripper plate may also be utilized on the mold as it opens for ejection of more detailed parts or those with negative-draft, undercut areas.
The sheet web remaining after the formed parts are trimmed is typically wound onto a take-up reel or fed into an inline granulator for recycling.
Electric servo motors are also used on some modern and more sophisticated forming machines for actuation of the machine platens where form and trim tooling are mounted, rather than air cylinders which have traditionally been the industry standard, giving more precise control over closing and opening speeds and timing of the tooling.
This stand-alone system connects directly to the thermoformer and utilizes multiple sensors to record production-run data in real time including air pressure, temperature, tool strain gauge and other specifications.
Thin-gauge thermoforming as described above is almost always performed on in-line machines and typically requires molds, plug assists, pressure boxes and all mounting plates as well as the trim tooling and stacker parts that pertain to the job.
Sheet thicknesses greater than 3 mm (0.120 inches) are usually delivered to the forming machine by hand or an auto-feed method already cut to final dimensions.
Aircraft windscreens and machine gun turret windows spurred the advance of heavy-gauge forming technology during World War II.
Olimunllum CF/PEEK is obtained by thick gauge thermoforming of thin layers of previously impregnated fibers to form fully consolidated sheets.
This allows easy design and post-processing using identical or similar tools as commonly used when working with metallic light-weight materials like aluminium, titanium and steel.