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Unread 16-01-2017, 17:40
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cadandcookies cadandcookies is offline
Director of Programs, GOFIRST
AKA: Nick Aarestad
FTC #9205 (The Iron Maidens)
Team Role: College Student
 
Join Date: Jan 2012
Rookie Year: 2009
Location: Minnesnowta
Posts: 1,565
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Re: FRC Bearing Load Ratings (Climber Winch)

Quote:
Originally Posted by Cog View Post
Yeah, as a team who used (or at least attempted to use) 3d printed wheel hubs I'd recommend steering clear of 3d printing for high stress applications. It went pretty terribly for us, and we had to switch out everything last minute. The type of hubs we used were just the VEX Versa hubs. I think the material was ABS but I can't be sure.
As a counterpoint, last year 2667 used 3D printed wheel hubs (with 8" wheels and the stock 42t AM HTD pulleys), made out of PLA and had precisely zero failures. If you're only running one regional, it MAY be fine, depending on the design of the part and the loading.

This is coming from the person who was EXTREMELY skeptical and made sure we printed half a dozen extras. Like with a lot of things, YMMV.

On the topic of climbers, this year 'Snow Problem designed one that used 4 1/2" hex bearings and a ~29" run of 1/2" 1018 steel hex shaft, with a bolt attached to a shaft collar serving as the "hook" for a loop. So far it has failed twice: once was the rope (turns out a random cord from a surplus store is NOT what you should be making your rope out of), and once from shearing the bolt, which was 1 1/2 or 2", 8-32 SHCS, alloy steel, and costs us about 10 cents and 10 minutes (if that) to replace.
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'Snow Problem CAD Files: 2015 2016
MN FTC Field Manager, FTA, CSA, Emcee
FLL Maybe NXT Year (09-10) -> FRC 2220 (11-14) -> FTC 9205(14-?)/FRC 2667 (15-16)
VEXU UMN (2015-??)
Volunteer since 2011
2013 RCA Winner (North Star Regional) (2220)
2016 Connect Award Winner (North Super Regional and World Championship) (9205)

Last edited by cadandcookies : 16-01-2017 at 17:45. Reason: added info on 'Snow Problem'
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