The most cost effective way to produce materials such as Acrylic or PEEK is to use either a casting or extrusion process. Although cost effective, cast acrylic or extruded PEEK materials can be highly stressed and have a surface skin which can pull and distort components during the manufacturing processes.

To ensure stable dimensions and a long life for precision machined component parts, it is essential that materials are correctly heat treated to remove internal stress. Carville will not manufacture plastic component parts without fully heat treating the base material at the pre-production stage.

On materials such as acrylic (PMMA), these initial heat treatment processes can result in material shrinkage of between 2% and 4%.

All plastic materials used by Carville are normalised using controlled heat treatment processes before any machining operations take place.

During the production process, all components are stage annealed to remove any stresses that may have been induced due to the machining processes.

Subject to the component size and the volume of material removed, heat treatment processes may be performed several times and may require up 3 to 5 days.