thermoformen

Thermoformen, in English known as thermoforming, is a manufacturing process in which a plastic sheet is heated to a pliable forming temperature, formed to a specific shape in a mold, and trimmed to create a finished part. The process is widely used for packaging, enclosures, panels, and consumer products. In German usage, the term Thermoformen is common and refers to the same process.

Most thermoforming uses vacuum forming or pressure forming. In vacuum forming, the heated sheet is clamped around the edges and drawn into a mold by a vacuum, with optional plug assists to improve wall thickness distribution and detail. In pressure forming, air pressure or a combination of vacuum and positive pressure pushes the sheet against the mold for finer features. Twin-sheet forming forms two sheets separately and then welds them to create hollow parts.

Process steps typically include clamping the sheet, heating it to the forming temperature, forming over a mold using vacuum and/or pressure, cooling, and trimming the excess material. Molds are usually made from aluminum, cured steel, or composites, designed with appropriate draft angles to facilitate release.

Materials commonly used in thermoforming include polystyrene, ABS, PETG, polycarbonate, acrylic, PVC, and various polyolefins. Sheet thicknesses generally range from about 0.5 to 6 mm, depending on part requirements and equipment. Formability, stiffness, clarity, and heat resistance are influenced by material choice.

Equipment ranges from small desktop devices to large industrial lines, incorporating ovens, forming stations, cooling stages, and trimming systems. Thermoforming offers lower tooling costs and faster prototyping for medium to large parts, but may provide less precise tolerances and surface detail than injection molding, with draft requirements and material limitations to consider.