To protect the mating connector from over mechanical stress and to minimize strain during board-to-board assembly, it is important to tighten the standoff nut in a specific sequence. The recommended mechanical standoff tightening sequence (S > W > N > E) is shown in the following figure. Once the S and W nuts are tightened, the SOM board is almost flat to the carrier card. The subsequent tightening of nuts N and E ensure the SOM and carrier connectors are completely engaged.
Figure 1.
K26 SOM Connector Mating Sequence
The recommended torque driver setting and operation parameters are specified in the following table.
| Torque Driver | Controller Module | Torque Driver | Torque Setting | Assembly Duration | RPM Setting for Each Step |
|---|---|---|---|---|---|
| Smart Torque Electrical Driver | Atlas Copco MTF600 | ETD M 50 ABL V2 |
3.0 in.lbs (±0.5 in.lbs) |
10 secs | Step 1: 300 RPM |
| Step 2: 600 RPM | |||||
| Step 3: 150 RPM |