Heat Treatment of Plastics
Heat Treating Plastics
Why Heat Treat Plastics?
The most cost effective way to produce materials such as Acrylic, PEEK or Ultem is to use either a casting or extrusion process. Although cost effective, cast acrylic or extruded engineering grade materials such as PEEK or Ultem can be highly stressed and have a surface skin which can pull and distort components during and after 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 source material oversize, skim to break the surface skin and then heat treat to remove the internal material stress. Carville will not manufacture machined plastic component parts without fully heat treating the base material at the pre-production stage.
What is the Impact of Heat Treatment?
On plastic materials such as acrylic (PMMA), the initial heat treatment, or normalisation processes, can result in material shrinkage of between 2% and 4%. This movement is a result of the material relaxing and releasing the internal stresses that have developed during the casting or extrusion processes.
Does Carville Heat Treat All Parts?
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 which may have been induced due to the machining operations.
Material normalisation and inter stage annealing ensures that acrylic and plastic components produced by Carville will have minimal material stress and will offer a long and reliable performance.
How Long Does Material Heat Treatment Require?
Subject to the component size, and the volume of material removed, the heat treatment processes may be performed several times during manufacturing operations. These heat treatment processes can add several days to the component manufacturing process which is why Carville’s lead-times are quoted in weeks rather than days.