Thermal expansion rates in plastics are higher than those in traditional engineering materials, making it essential to account for these differences when designing and manufacturing plastic parts. This is particularly crucial for long parts like Chain Guides and Wear Strips made from UHMWPE (Polystone).
Ignoring thermal expansion can lead to issues such as buckling of UHMWPE Wear Strips.
The most important thing when designing for thermal expansion is to allow the expansion to occur, and not try to restrain it. This can be done by
1. Allowing for movement at the fastener. As illustrated , having an oversized hole and a generous washer.
2. Leaving a gap between wear strips to allow for thermal expansion. Below are a couple of options on how to achieve this.
The size of the expansion joints and the clearance for the fasteners can vary based on the temperature changes and the length of the parts.
For technical support in this area please feel free to contact your local Dotmar office or one of our engineers.
