Have you ever been working on a design where you think that just about any rigid or soft material will be a good option, only to discover that the material selected underperforms in the finished state? I know over my career that I have seen this many times. Proper material selection is critical in making sure that you achieve the desired end result. There are multiple things that need to be considered in selecting the proper material for a given application. How hard or soft does the material need to be, what is the durometer? How much does the end component need to flex, what modulus should we target? Are there any harsh environmental considerations, heat, corrosive chemicals, etc.? All of these are questions that help provide our customers with a component that will perform at a high level.
The one I am going to touch on specifically is durometer. What is durometer, and how does it impact performance.
Durometer in its simplest form is the measure of the hardness of materials. In OMNI's case we are specifically referring to elastomeric materials. Durometer is measured using special gauges for a very specific scale in the durometer spectrum. Durometers of elastomeric materials vary greatly from extremely soft in the Shore 00 scale, think of a gummy bear, to very hard in the Shore D scale similar to a bowling ball or hard hat. The way that materials are tested is by bringing a blunt (Shore A) or pointed (Shore D) probe into the material at a specific load rating. The further the probe is depressed the harder the material is.
Durometer plays a big part in the resiliency of the material. If you are looking for a material that needs to grip a product but needs to withstand sliding abrasion, you will find that materials harder in the Shore A scale will be better with abrasion resistance while maintaining grip. If you are looking to decrease COF, then materials in the Shore D scale will provide you with less drag. One of the reasons that polyurethane makes for an excellent material is that the durometer range in this polymer group covers the gamut. Although we have the ability to manufacture parts in any durometer, physical properties are maximized between 50A and 80D. When you get too much higher on the Shore D scale, the materials start to become brittle, and likewise on the Shore A scale the materials cut, tear, and rebound resilience are compromised.
When OMNI looks at applications with our customers, we first look to understand the dynamics that will be placed on the material. From there we can start looking at modulus required and formulate materials in the right durometer range that would give us optimal physical properties. Our goal at OMNI is help develop long lasting products that perform just like you designed them to. If you have questions about materials and physical properties, leave us a comment or reach out to your OMNI Rep.
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