Heat Sink Grease : Robot Events

The Q&A is closed for the 2021-2022 season. Any rule changes or clarifications pertaining to the 2022 VEX Robotics World Championship will be included in the April 5 Game Manual Update. Teams attending VEX Worlds who wish to pre-submit questions for the driver's meeting should have received a contact form via email; if not, please contact your REC Foundation Team Engagement Manager for more information.

Usage Guidelines All Questions

Heat Sink Grease

631A

23-Jan-2022

According to R8, "Any non-aerosol based grease" may be used. Does this rule allow heat sink grease typically used to transfer heat from CPUs to heat sinks in order to avoid overheating the processor or is it expressly intended for lubricants?

Is it within the rules to build motor heat sinks with aluminum structure / heat sink grease?

Tetrafluoroethane and difluoroethane, which are both used in canned air dusters many teams are using to cool motors, are ozone depleting chemicals (along with other potential health hazards for the students such as leading to addiction).

Also consider the present supply chain issues with V5 smart motors.

Allowing teams to construct (or even if VEX could offer) heat sinks with heat sink grease in order to avoid cooked motors would be a significant benefit to the teams.

Additionally, this opens the opportunity for the students to learn about cooling design for components (such as available using Autodesk and Solidworks). Something like:

https://help.solidworks.com/2022/english/SolidWorks/cosmosxpresshelp/c_Thermal_Analysis.htm

Is this allowed within the scope of R8?

Cheers,

Joe Kennedy

Answered by committee

In general, it is always difficult to provide absolute blanket rulings based on broad descriptions of hypothetical mechanisms. So, we cannot definitively say "no, heat sinks are not legal". However, the specifics of this question do imply many things that are, themselves, not legal.

Does this rule allow heat sink grease typically used to transfer heat from CPUs to heat sinks in order to avoid overheating the processor or is it expressly intended for lubricants?

No, it is intended to expressly refer to lubricants. The full text of R8-b reads as follows:

Any non-aerosol based grease or lubricating compound, when used in extreme moderation on surfaces and locations that do NOT contact the playing field walls, foam field surface, Scoring Objects, or other Robots.

Although thermal paste is technically a non-aerosol based grease, we would not recommend using it as a lubricant.

Regarding the construction of a functional motor heat sink, we must also reference R21-c:

<R21> No modifications to electronic components are allowed. Motors (including the internal PTC or Smart Motor firmware), microcontrollers (including V5 Robot Brain firmware), extension cords, sensors, controllers, battery packs, reservoirs, solenoids, pneumatic cylinders, and any other electrical component or pneumatics component of the VEX platform may NOT be altered from their original state in ANY way.

c. Teams may make the following modifications to the V5 Smart Motor’s user-serviceable features. No other modifications are permitted.

i. Changing or replacing the gear cartridge with other official replacement cartridges.

ii. Replacing the V5 Smart Motor Cap (276-6780).

iii. Replacing the threaded mounting inserts (276-6781).

Official Q&A: VRC 2021-2022: Tipping Point

Heat Sink Grease