Board Vibration Mounting

Owned by Hanqi Zhao
Last updated: Jun 03, 2020
3 min read

The following is a recap of mounting techniques for our car’s PCBs to minimize board vibration and damage during race conditions. This is important as violent and constant mechanical stress can break connections on the board and result in a loss of functionality.

Currently we are using 3D printed mounts and heat set inserts that are pushed into the 3D print. Heat set insert information can be found here: link. From MS12 to MS14, we wanted to match any and all automotive industry standards to diminish the effects of vibration.

1st Mounting Technique: PCB Mounting Feet

This is a very common way to create a standoff between the PCB and the base it is attached to.

By preventing direct contact, it provides additional protection against base vibrations.

The picture above shows an example of the PCB foot. It is a 90 degree piece of plastic with a tapped hole to screw in the PCB and secure it to a base such as a wooden board. A few notes about the PCB feet:

  1. Very cheap option.

    1. You are able to buy these feet and screws in packs of 40+ for a relatively low cost

  2. Easy to implement.

    1. All that is needed is to tap a hole in the PCB corners and attach the feet/PCB configuration to a central base

  3. Able to resist torsion.

    1. The more of these feet we screw along the corners/edges of the PCB, the more rigid the PCB becomes and is better able to resist torsion

  4. Board Fragility.

    1. Any puncture along the board’s edges or corner increases the risk of crack propagation throughout the board.

    2. It is recommended to avoid puncturing a hole right against the edge/corner of a PCB

As shown above, it is better to leave some space between the screw (S) and any corner/edge.

As illustrated in the first picture the PCB will have to be mounted to a base. It is recommended that the base be wooden. Wood is lighter than metal, cheaper than metal, and is a viscoelastic material. This means it can better dissipate energy such as mechanical vibration.

2nd Mounting Technique: Epoxy

The second method is more simplistic. It involves smearing clear epoxy resin onto the mounting base and gluing the PCBs onto it. A few notes about this method:

  1. Cheap

    1. I believe we still have some left over clear epoxy resin in the bay

  2. It is permanent

    1. Once the epoxy goes on and is hardened, it is hard to change the location of the PCB or make alterations

  3. Not very effective

    1. The lack of elevation from the base in addition to the potential for vibration resonance makes this a risky solution

    2. Resin can be used in addition to another mounting strategy but should not replace it all together