Thermoformed materials are found virtually everywhere — computer shells that many people gaze within for eight or more hours a day, the knobs on your car stereo or the telephone that pleads for your attention. More well-known to the sign industry, however, pan and embossed thermoformed faces comprise a large portion of the business for wholesalers and larger electric-sign companies.
ST spoke with several companies involved with thermoforming plastic sheets. With this overview, they offer insights.
Thermoforming basics
There are two types of thermoforming: pressure forming and vacuum forming. Pressure forming typically uses thin-gauge plastics for small objects that are made in large quantities, while vacuum forming is done for pan-faced signs, which have a more significant margin for error.
Thermoforming incorporates thermoplastics, of which there are two types: amorphous and semi-crystalline. Because semi-crystalline materials (such as polypropylene and polyethylene) tend to turn limp under severe heat, amorphous materials — such as polycarbonate and conventional and impact-modified acrylic (IMA), as well as lesser amounts of acrylonite butadiene styrene (ABS) and polyvinyl chloride (PVC) — are generally used for vacuum forming.
Thermoforming requires a temperature range of 300