Material Selection Assistance
The range of polymer choices continues to increase as resin manufacturers synthesize novel homopolymers and copolymers, compounders create polymer blends and additives packages, and processors perform finishing steps such as crosslinking and surface treatments. Polymeric materials range from rigid UHMWPE and PEEK, to flexible TPEs, films, and woven constructs, to soft hydrogels.
Whether you are designing a new product with exotic performance requirements, conceiving of a novel application for an existing concept, trying to improve the performance of your material by upgrading the specifications of the components, or simply trying to replace an existing material with an equivalent from a different vendor, Cambridge Polymer Group can help.
WHAT IS YOUR TARGET APPLICATION?
The selection of a polymeric material requires careful thought and knowledge of both the plastic and the target application, and how each will respond to the other. When we assist clients in selecting polymers for their products, the project always starts with a detailed description of the target application. What is the expected environment for your product? Is your product intended to be permanent or is deliberate degradation desirable? If the latter, over what time scale?
We then ask about your product design to get a sense of what material properties will be important. If known, target material properties, such as tensile strength, modulus in the relevant loading condition, wear rates, or pore size, are listed as required specifications. This information is often the result of computer simulation of your product design in its target application area. Often, the required specifications or material behavior inputs for simulation are not known, and some initial guesses have to be made, to be verified later during screening tests.
As part of this discussion, the potential manufacturing process is considered, which will further aid in polymer identification. In some designs, injection molding is required, while others may require film extrusion, compression molding, ultrasonic welding, or fiber spinning. The use of additive manufacturing has further expanded the consideration of material selection. Storage life of the plastic is relevant for inventory control, as is secondary sources of the material. Lastly, the cleaning process (and disinfection/sterilization process, if applicable) has to be considered, since these processes can affect some polymer materials.
MATERIAL SELECTION & TESTING
We then begin assembling a list of candidate materials, normally starting with materials that meet the known property requirements. This material list can be filtered by materials already used in your target application, or a similar application. Any relevant regulatory or standardized testing requirements are considered. There are many cases where an off-the-shelf solution does not exist, but a custom formulation or modification of an off-the-shelf solution can be provided.
After the list of candidate materials has been reviewed with the client, selected candidate materials will be ordered. At this point, we will often perform specific tests on the materials relevant to the client’s target application that are beyond the standard mechanical property tests provided by the resin manufacturer. These tests may include standard or custom fatigue tests, oxidation resistance tests, extractables/leachables, or processability tests. Based on results of these tests, the list of candidate materials can be further reduced.
From this reduced list, we or the client will then make prototype assemblies of the target product, in order to test manufacturing processes and to evaluate the potential failure modes of the product with the candidate materials. Based on these results, the material criteria may be further modified, the design may be adjusted, or a candidate material may rise to the top.
Of course, the cost of the polymer is an important consideration. Depending on the anticipated volume and price point of your product, pricing considerations may be a primary criterion, or a secondary one. The actual polymer pricing depends heavily on volume and form factors.
MATERIAL SELECTION VALIDATION
Our broad range of clients and personal backgrounds mean that we have an almost unique capability not only in determining the material you need, based on your specific requirements, but also in validating that choice in conventional (ASTM for example) tests, or in custom tests tailored to your application. We have provided this service to biomedical as well as heavy industry and consumer clients. This breadth of expertise, coupled with our physical, chemical and mechanical understanding of materials and applications makes us an invaluable resource if you need a new material, or simply want to replace an old one.
Contact us to discuss how we can help with your material selection.