Some connectors datasheets specify the following:
Metal-to-metal bottoming for maximum EMI shielding under extreme vibration
Reference: Dualok Connectors
I have also encountered the following for a similar component:
Improved shielding resistance due to shell to shell bottoming.
Perhaps the following definition applies:
- to place (something) on or upon a foundation; base
However, this is still unclear to me. What does bottoming mean in this context?
What does metal to metal bottoming mean?
It means that when you attach the mating half, the metal of the mating half naturally touches the metal of the connector and forms a complete Faraday cage around the connection point. In the picture below it's called metal to metal mating: -
As Andy stated, electrically speaking, it means the two metals are in direct physical contact.
Here is more specific information relating to the word "bottoming" from sheetmetal.me:
Bottom bending is the process of stamps the radius of the punch tip into the work piece. [...] The work piece is first bottomed against the die, then the radius of the punch is forced into the work piece which achieves the angle of the punch, it is then released and the work piece springs back to meet the die again.
It is important to note that bonding/fastening of metals does not always imply good conductance. There can be impurities in-between (dirt/fluxes/etc) or there could be great contact at first but then the pieces may shake loose/rattle during vibration, causing difficult to diagnose issues when conductivity is needed.
Bottoming can help assure that pieces do not vibrate out of place.
