Re: VEX PRO. To use it or not to use it.
 

To be perfectly honest, I don't know their rationale either.

Here's proof from PIC. (Most of the aluminum gears in that catalogue are notated "Anodized Before Cutting".) And similarly for SDP/SI. (Typical of their 2024 aluminum gears, but not the 5052 aluminum ones.)

Re: VEX PRO. To use it or not to use it.
 

I could understand it on fine pitch gears. As DMike pointed out, it'd be difficult to get good coating thickness down in the teeth, and you'd probably yield the teeth before you built up enough pressure that galling and wear became a problem.

Re: VEX PRO. To use it or not to use it.
 

I know the coating/ano affects the tooth shape. For that reason I know WCP modifies their gear profile to account for the coating and ano. Does vex do this too?

Re: VEX PRO. To use it or not to use it.
 

Yes we do. :)

-John

Re: VEX PRO. To use it or not to use it.
 

Whether wear or yield/fatigue failure comes first depends on a lot of design parameters, which are mostly accounted for if you look at say, the AGMA gear design methodology and equations. Most undergraduate-level machine design textbooks will have this in detailed form.

I'd be careful about generalizing the statement, but for FRC purposes I'd guess you're usually right if gearboxes are designed and sized appropriately for the application, since our designs are generally very intermittent (what's the actual use life of an FRC robot? A couple hundred hours tops?) so wear is usually not as much a factor as the fatigue caused by the shock loads.

Re: VEX PRO. To use it or not to use it.
 

Yes, I know that this is a terrible reason to make a design decision, but as one of our mentors pointed out, "JVN was involved in the design; It has to be good!" :D