Thermoforming
Pronunciation: ther-moh-FORM-ing
The fabrication process in which thermoplastic sheet material is heated until pliable and then moulded over a positive model to form the shell of an orthosis.
Full Definition
Thermoforming is the primary method of fabricating rigid and semi-rigid plastic orthoses in modern orthotic practice. A sheet of thermoplastic material—such as polypropylene or polyethylene—is heated in an oven until softened, then draped or vacuum-formed over a positive plaster or CAD-CAM model of the patient's limb. Once cooled, the formed shell is trimmed, finished, and fitted. Understanding the fabrication method is important for editors reviewing orthotic service specifications, tender documents, and clinical audit reports, as thermoforming affects material choice, turnaround time, and device properties. Editors should not confuse thermoforming with lamination, which uses resin and fibre layers.
Usage
Usage note: Distinguish from 'lamination' (a different fabrication method using resins). Specify the material used (e.g., polypropylene) when thermoforming is referenced in clinical or procurement documents.
In Context
- "The orthosis was fabricated by thermoforming 4 mm polypropylene over a plaster positive of the patient's foot." — Fabrication worksheet
- "The tender specification required that all rigid AFOs be manufactured using thermoforming rather than lamination techniques." — NHS procurement document