It has long been recognized that the extrusion process utilized to manufacture sheet stock suitable for vacuum thermoforming imparts an orientation to the polymer structure. The orientation can result in shrinkage in the finished clinical device. New material testing results indicate that there is not only an orientation differential but also a stiffness or flexural modulus differential between the extruded machine direction and the transverse direction in the sheet stock. The clinical advent of tuning AFOs for a patient should also respect fabrication tuning for the best outcome in the custom device. A primer on the polymer structure and the physical characteristics based on the new findings will be presented.
Learning Objectives:
Technicians will be able to recognize the importance of aligning the machine direction of the extruded sheet to minimize shrinkage impact.
The attendees will also be exposed to alternative thermoplastic composite materials that overcome extrusion shrinkage.
