our robot is 15 lbs over weight. :eek: we need all the advice we can get to help us LOSE THE WEIGHT! any suggestion would be appreciated…thanks.
If you posted a picture, it would probably help others offer advice.
are you aware that they changed the rules: this year the robot is weighed withOUT the battery?
If you are using the kit frame, drill out all of the holes in it to one drill size larger (I think its 3/8 not sure…) this takes about 3-4 lbs out of the frame while keeping the integrity.
Lexan panels love hole saws and so do metal plates as well as wooden parts.
Wheels could use some holes drilled in them, not too many though.
Gears should be turned down to a smaller hub, but not too small. And then holes can be drilled in them as well.
Next is the electrical where wires can be shortened to exactly the length needed so as not to have extraneous wiring.
Then after that replace all of your team identification panels and things with a simple piece of paper, nothing fancy.
Round the corners on everything, surprisingly this takes off quite a bit.
Bolts that are too long should either be cut off or replaced.
Steel shafts should be traded out for aluminum ones if there isn’t a large load on them.
If this doesn’t work then take off some features or remove the least necessary structural supports (not advised). Just drill holes until it looks like Swiss. You wont be the only one!
Be sure not to weigh the robot without the 12V battery and without the bumpers. The backup battery must still be on the robot durring weigh in.
Also you can change out hardware that isn’t truly load bearing from steel to aluminum and even nylon nuts and bolts instead of the standard steel.
Electrically, shorten the runs up and even electrical systems to keep the high voltage cables as short as possible, eg victors right next to the distribution block, right next to the battery and motor.
Lastly replace any tubing with thinner walled tubing and lexan with thinner lexan, 1/16 to 1/32
change you sprockets to aluminum.
www.andymark.biz sells exact replacements to the ones in the kit but are much less in weight.
^ one negation too many here?
the robot is weighed with out the main (big) battery this year, but the backup 7.2 V battery must be present - correct?
Indeed, two years ago our teams bot arrived in Manchester completed but very overweight (it was 20 lbs to start with right before crating, but losing a major part of our arm dropped us to 7 lbs overweight). 7 lbs is a lot to lose if you don’t have obvious parts to remove. A large fraction of pit day was spent shedding weight from the bot, to the point where the officials told us not to come back until we were sure we were underweight (but let us weigh a bag of parts between other bots, so we figured out our weight loss that way). Too much time was spent with sawzalls and hole saws, arguing with each other about where to cut and how much. And too much time removing every other bolts, almost all the washers, sanding, filing, shortening wires, substituting lighter components, etc. Some of the saga was capured here. (As an aside, we were a regional finalist at Palmetto later that season).
Seriously, I’m glad you’re removing weight now, since I don’t recommend this approach. Lose the weight now, and not later.
It’s late in the building season but re engineering certain components give you the chance to improve upon them as well as losing weight…
you can save yourself from drilling speed holes by meerly replacing whatever material sheet you have with something thinner. Just think about how many speed holes you need to drill before you cut the weight of something in half.
yeah sorry about that. I took one quick look over this before i posted and ended up with a double negative, most of the time i end up with a tripple negative.
327 1/2" holes in 1/8" thick 6061 aluminum makes you loose 1 pound if you have alot of frame material
BE CAREFULL if you start drilling holes in your robot to drop the weight because you dont realize how addictive it becomes
and sooner or later you end up with stuff like this in your pocket
and you dont remember how it happened!
Pay attention to the above quote. 327 1/2 in holes is a LOT of work for 1 lb. Look at a lighter design first.
Steel 1rst, then Aluminum, then Plastic
Get the biggest “bang for your buck”
does that keep it from ripping up your jeans pockets?
i like the pattern… except i think drilling gets annoying. already ive drilled over 100 1/2in holes all over… we still need to drop more if we want to protect stuff…
Word of caution, be careful with this. We have warped gears before in the homemade transmission our first year (before the 2005 KoP ones) and that really wasnt good.
Don’t forget to be careful if you take large areas out of both gears and sprockets. We did that one year, but didn’t find out until that fall, when we broke that sprocket at a postseason.