2.2.5.5 Expected Life of the Assembly
The following are two important considerations in determining the expected life of an assembly:
1. Does the assembly require corrosion protection, or will the parts corrode by design?
2. Is dismantling required for maintenance of the assembly, and if yes, how frequently?
Joining method selection depends on the requirements of an assembly. Rivets or bolts cannot seal against the environment. Welding joints can seal; however, they become a starting point of corrosion in many cases, often due to the flux used during welding processes. Hem joints bonded with adhesives are the preferred choice of assembly design (commonly used in the automotive industry) to prevent corrosion and maximise the lifetime of the assembly. Bonded substrates will seal; however, dismantling bonded parts can be challenging.