Metal bellows

When the pressure or vacuum is released, the bellows will return to its original shape, provided the material has not been stressed past its yield strength.

Hydroformed bellows generally have a high tooling cost, but, when mass-produced, may have a lower piece price.

However, hydroformed bellows have lower performance characteristics due to relatively thick walls and high stiffness.

Welded metal bellows are produced with a lower initial tooling cost and maintain higher performance characteristics.

Other advantages to welded bellows include compactness (higher performance in a smaller package), ability to be compressed to solid height with no damage, resistance to nicks and dents, and dramatically greater flexibility.

The various types of deflections are axial, lateral, angular, torsional, cyclic, or any combination that can occur at the same time.