Ulrich Endemann and Andreas Magerlein
The selection of a material should always be carried out thoroughly. The result always has an essential influence on the properties of the produced part, the design, production process, and finally the total parts cost.
How to Select the Right Material
Normally, a material is defined through an iterative process. The engineer’s challenge is to choose from over 30000 different types of plastics the right one for the application. This enormous variety of plastic grades results from the possibility of modifying their formulation and thus creating tailor-made plastic grades.
To pre-select a basic material, first thermal, then chemical, then mechanical, and finally all other requirements are taken into account. Accordingly, the maximum operating temperature needs to be known as well as the types of chemical environments that could occur (e. g., processing fluids, cleaning agents, etc.). Even the influence of weathering needs to be known, after which plastics grades can be selected that are weathering-resistant or, if this is not possible, a material that can be coated with a UV-resistant paint or coating.
A crucial aspect when choosing a material is the engineer’s objective and his freedom to design. Many plastic parts are designed to replace other materials, especially metals. In such cases the requirement profile often follows that of an existing metal part. If the design is not about a single part but a complete system that has to fulfill different functions (e. g., a solar collector), it is reasonable to think about new design concepts and production processes. For instance it is conceivable that a foamed polymer structure can be used to insulate and simultaneously stiffen the structure.
Polymeric Materials for Solar Thermal Applications, First Edition. M. Kohl, M. G. Meir, P. Papillon,
G. M. Wallner, and S. Saile
© 2012 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2012 by Wiley-VCH Verlag GmbH & Co. KGaA.
212 I 11 Plastics Properties and Material Selection