When creating custom foam gaskets, or any other type of custom gasket, one of the single most important considerations is the material from which they’re made. Even among foam gaskets, there are numerous types of elastomers that could be used – and they’re all going to have different properties when put into use.
Many of these are obvious, like “Can this material stand up to expected working temperatures?” However, others are less obvious, particularly when it comes to longer-term usage. Compression setand stress relaxation are two problems that can develop in gaskets being used, and they need to be considered carefully to ensure your products function reliably for your customers.
How Compression Setting and Stress Relaxation Affect Custom Foam Gaskets
I. Compression Setting
Compression set (or “C-Set” for short) refers to the tendency of foam gaskets to lose their elasticity when put under compression. In general, no foam gasket will ever regain 100% of its original elasticity when compressed and then released, but it’s vital that the type of foam be chosen to minimize this effect. C-Set can also be affected by operating temperatures, particularly high temperatures.
So, for example, silicone foams have good C-Set at room temperature, whereas a neoprene/EPDM blend performs poorly at the same temperature. Your custom gasket manufacturer should be giving as much information as possible about the expected operational parameters of your custom gaskets, to ensure they pick appropriate materials.
II. Stress Relaxation
Stress relaxation refers to the tendency of foam gaskets to lose their ability to deflect additional forces while under a heavy compressive load – ie, how ‘springy’ they are. In some cases, this isn’t an issue, but it can cause problems when these gaskets are used in applications where they’ll be under multiple simultaneous stresses.
Generally, stress relaxation is predictable with foam materials. They will each lose a set amount of resilience during usage but won’t degrade further once they’ve hit their natural stress relaxation point. So, again, a custom gasket manufacturer must choose the material carefully, to ensure that its natural level of stress relaxation won’t interfere with intended usage.
For Top-Quality Custom Foam Gaskets, Call in Expert Gasket & Seal
Our expert staff has extensive experience working with a huge range of gasket materials, and we love taking on new challenges! If you have a sealing problem that your engineers can’t overcome, contact us and we’ll find a solution that works.