Context
This page was created by Daniel Puratich to standardize how custom hardware is designed with respect to mounting hole dimensions and mounting patterns during the 2023 competition cycle and is being improved over time.
Specification
For general custom EE flight PCBAs going forward we will follow this mechanical mounting hole specification:
M3 - Any PCBA with area exceeding 2500 mm^2
3.400mm hole diameter (0.1mm tolerance)
6.000mm annular ring diameter
M2 - Any PCBA with area exceeding 750mm^2 and less than 2500mm^2
2.400mm hole diameter (0.1mm tolerance)
4.200mm annular ring diameter
No Mounting Holes - Any PCBA with area less than 750mm^2
No mounting holes will be present on board of this size.
All Mounting Holes will follow:
electrically not connected to the PCBA (frame is ideally floating potential)
Eight vias (plated drills) placed evenly in the annular ring (in whichever drill size is used on the board (so effectively left to EE in charge to decide on via size)) for mechanical stiffness.
Electrical component soldering pads should be at least 1mm away from the annular ring to avoid damaging the PCBA when mechanically bolting the board.
Mounting Hole pattern will be:
The 30x30mm hole pattern is commonly used in COTS world so we’re picking that up on WARG as well.
Information
See RFC Request: 2023-02-11 - EE Hardware Mounting Hole Specification
System Architecture: 2023 System Architecture
RFC Discussion: RFC Forum