BaneBots p60 falure

[Hawiian Cadder]

at our regional we had a p60 fail in a way i have not ever seen before, and i was wondering if any other teams had advice on how to prevent this.

an 1-81 P60 with an rs550 on our roller got hit by another robot, and the 4 screws that hold the gearbox together pulled out all of the threads in the aluminum block on the motor side of the gearbox. it was repaired by putting 2 screws in either side, and using an FTC threaded standoff in the middle. this solution worked O.K.

has anyone else had this problem

[Tristan Lall]

Easy answer: don't mount it where it's going to get hit! (Or shield it.)

Somewhat more complicated answer: this could be a manufacturing problem related to a series of poorly-tapped mounting holes. It could also be an inadequate piece of aluminum—maybe the wrong temper or alloy, leading to unexpectedly low pullout strength. Maybe the tie rods are threaded with too small a thread in the first place—but it's hard to say for sure what's adequate, since I doubt that BaneBots intended that the gearbox be exposed to large tensile loads. (Does it look like the thread was scraped off of either the tie rods or the inside of the holes?)

Do you have any pictures of the failed parts?

[AdamHeard]

When our gearboxes arrived, we noticed the provided screws were of poor quality, and that they only threaded into the block maybe .080", tops (the block is .3" thick). Different number of stages will change what screws are provided, but I would imagine similar issues could exist among all types.

We replaced them with proper length, and quality screws.

[Tristan Lall]

Originally Posted by AdamHeard

When our gearboxes arrived, we noticed the provided screws were of poor quality, and that they only threaded into the block maybe .080", tops (the block is .3" thick).

Will BaneBots ever get the simple things right?

[Ninja_Bait]

The same thing happened to us in build season. We had some older gearboxes which were really solid and had partially threaded socket head bolts that were about 1/2" longer than the gearbox, but the new ones come with screws that are just asking to get stripped. Who knows why BB changed the screws, but the solution is definitely longer screws right after you grease your gearboxes.