thermoforming

Thermoforming is a manufacturing process in which a thermoplastic sheet is heated to a pliable forming temperature, formed to a profile using a mold, and trimmed to create a final part. The process is commonly used for relatively large parts with simple or medium-complex geometry and is valued for lower tooling costs and shorter lead times compared to Injection Molding.

In typical thermoforming, a flat thermoplastic sheet is preheated until soft enough to form. The sheet is then drawn over or into a mold by applying vacuum (vacuum forming), air pressure (pressure forming), or a combination of both. Some systems use male or female molds and may employ single-sheet or twin-sheet forming. After forming, the part is cooled to solidify, and trimming removes excess material and produces the finished edge.

Materials used are thermoplastics that can be reheated, such as polystyrene, PET, PETG, ABS, polycarbonate, and acrylic. Common sheet thicknesses range from about 0.020 to 0.500 inches, depending on size and requirements. Equipment ranges from simple bench-top machines to large production lines, including vacuum-forming machines, pressure-forming machines, and twin-sheet lines for hollow or double-sided parts.

Applications span packaging (clamshells, blister packs, and trays), consumer electronics housings, automotive interior panels and trays, appliance components, and medical or display trays. Thermoforming offers advantages such as low tooling cost, rapid prototyping, and suitability for large parts, but it has limitations in feature detail, tolerances, and material thickness uniformity, requiring careful mold design and process control.

Quality issues include warpage, thinning, sinks or voids, and flashing. Recycling and scrap reprocessing are common with material waste managed in line with environmental practices.