Elastomer seals are unlike any other materials that design engineers confront. Metal or plastic parts, for instance, are probably failing if visibly distorted. Seals deform into leak paths to function properly. In most applications, o-rings are installed with preset squeeze and stretch as correct design intent.
For customers who require custom molded shapes and/or housing seals, Apple Rubber uses a go/no go gauge to better ensure that they're receiving quality parts that meet their dimensional requirements. Here's how it works.