One factor that most people may not be aware of is the potential damage to the contact spring. Although the time and temperature of exposure to the contact spring may be too short, it is always possible that the finish on the contact interface may suffer damage. The welding process will cause diffusion on the base metal and may oxidize the coating. Increased oxidation on contact may increase resistance to unacceptable levels. Copper diffusion through gold is very common and causes problems especially under low voltage and current applications.
In the process of producing connectors, before deciding to solder the contacts, the general soldering ability of the contacts must be observed. Be sure to take into account the shelf life, issues related to diffusion, IMC growth and corrosion. In particular, the components involved must maintain solderability in terms of solderability from the time of soldering. These items include: terminals, solder tails, pads, and plated through holes drilled into the PCB.
The shelf life and storage of components are more important than many people realize. Climate control is essential for items stored for long periods of time, especially in terms of temperature and humidity. When transporting on a ship, climate control is particularly important. Corrosive agents in the storage area can become increasingly dangerous to the product. If the storage environment seems likely to threaten the solderability of the connector, the components may need to be thoroughly inspected and tested. The method of dipping and observing through the meniscus or the wetting balance is a suitable choice for testing. If these items are deliberately exposed to these conditions for a long period of time, appropriate precautions must be taken and adequate testing must be carried out after the fact.
