View Single Post
  #13   Spotlight this post!  
Unread 31-01-2016, 08:33
Joe Johnson's Avatar Unsung FIRST Hero
Joe Johnson Joe Johnson is offline
Engineer at Medrobotics
AKA: Dr. Joe
FRC #0088 (TJ2)
Team Role: Engineer
 
Join Date: May 2001
Rookie Year: 1996
Location: Raynham, MA
Posts: 2,633
Joe Johnson has a reputation beyond reputeJoe Johnson has a reputation beyond reputeJoe Johnson has a reputation beyond reputeJoe Johnson has a reputation beyond reputeJoe Johnson has a reputation beyond reputeJoe Johnson has a reputation beyond reputeJoe Johnson has a reputation beyond reputeJoe Johnson has a reputation beyond reputeJoe Johnson has a reputation beyond reputeJoe Johnson has a reputation beyond reputeJoe Johnson has a reputation beyond repute
Re: Brown out / breaker trips with Pneumatic Tires

Quote:
Originally Posted by Chris Mounts View Post
(snip)

Joe: Chain may fix this for us. Thanks for the suggestion. Also...your cutting ABS sprockets for drive trains As someone who loves laser cut ABS that never occurred to me. About 40% of our robot last year was ABS. Do they hold up as sprockets?
I love ABS sprockets. The hold up nicely if you can follow the rules.
#1 keep the chain tight (preferably by having a good chain tensioning system designed in from the start)
#2 keep the sprockets and chain aligned and in one plane
#3 all torque transfer sprockets have over 120 degrees of wrap.

If you break these rules and the chain jumps, ABS is going to get munched much more than aluminum but that's the way the cookie crumbles.

For #25 chain:
I typically use 1/8 ABS sheet with bevelled edges for the teeth and make a sandwich with 1/8 sheets on the sides. ABS solvent bonding glue is your friend (and amazing).

For #35 chain:
You can use the above technique or you can make a one piece no glue design by using 1/4 ABS sheet but you need to really bevel the edges. If you have a belt sander and patience it isn't too hard. Makes a mess but the results are nice.

As always, YMMV

Good luck

Dr. Joe J
__________________
Joseph M. Johnson, Ph.D., P.E.
Mentor
Team #88, TJ2