Chief Delphi - Got Weight?

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Today we finally got a chance to weigh our robot, and much to our suprise we came in at an alarming 160 lbs. Didn't see that coming.

We weighed it with the battery, though, so we are only about 25 lbs overweight. 8 hours of drilling/punching/crying, we got rid of an excess 15 pounds or so, but we still have a ways to go. We may only have 2 motors for our drivetrain in the end...

Oh well, lesson learned.

Quote:

Originally Posted by JVN

You could replace heavy steel sprockets with lightweight aluminum ones.
That might save a few pounds.

Or even nylon sprockets. We've been using them for our drive wheels the past two years. Just be careful about using them in very high torque areas.

One little piece of advice, look at the game footage from recent and try to prioritize what is most important, because if you design the robot and plan for 4 drive motors then only have 2, you might have problems as well as the system itself so look carefully before taking out portions of systems.
Otherwise, drill away as the omni bit is your friend

If you have a lot of lexan on your bot, you may want to invest in a hole saw bit. Example, we had a lot of lexan on our bot...we weighed in at a cool 128 lbs. After removing un needed metal and making our bot very holy, we are down to 89lbs (and fast) :-)

Just remember that structural support is very important. Often you can drill holes as needed, provided you know what you are drilling into.

Good luck!

Last year we were about 20lbs overweight. Its supprizing how little material is really needed for structural stability. We removed 8lbs of aluminum from our arm- boy that was a long night. We also replaced about 5lbs of steel bolts with plastic ones. They really dont come close to reaching their yeild strength.

This year, thanks to keeping track of the weight as we built, were at a cool 90lbs!

thanks but we just had to get lighter materials and now were under

If you are using PVC pipe anywhere, try using ABS instead. We had to replace our PVC pipe rollers with ABS. If we could have found the very thin (say 1/16") ABS drain or vent pipe, we would have used that. There is also electrical conduit that is a foamed core PVC which is quite a bit lighter.

Some of the electrical components and non-stress items can be held on with nylon fasteners.

Steel sprockets can be shaved down quite a bit if you have machining facilities. If not, ask a local community college that has machining courses.

If you are using the kit frame, there's ways you can cut out a lot where the frame rails and joining pieces overlap since it seems to be a bit overkill.

Depending on the nature of the joint, you may be able to use a smaller but stronger bolt. One year, we used 10-32 allen head cap screws to hold our entire frame together rather than 1/4 inch bolts. A good grade of 10-32 is about as strong as a crummy hardeware store 1/4 inch bolt made with soft steel. We prefer grade 5 and grade 8 fasteners. You might be able to have some joints in aluminum welded to reduce the weight of overlapping sections and bolts. You may be able to grind a bit off the tops of bolt heads.

If you are using a converor belt of some sort, perhaps you can punch holes in it. We used some 2 ft wide rubberized cloth conveyor belt, similar to what tou'd see at a grocery checkout but fairly thin. Tough stuff, but very heavy. We sharpened up the end of a piece of small diameter car exhaust tubing and pounded out about 250 holes, cookie-cutter style. Had to use soapy water to get it to cut cleanly, and sharpened often.

Yeah, a little too much weight :D

Swiss Cheesing it.....overtime

We weighed in five lbs over weight, but since we have a lexan tube surrounding our spiral, we will most likely be making it more air than actual material.

Hehehe drills.

For the random comment, anybody see the Strongbad where he drills Strongsads bellybutton? Its under an episode about how the stick got its place/name/something.

Quote:

Originally Posted by Tom Bottiglieri

Take the white space out of your program.

... and the comments. Nothing worse than weighty comments!

Quote:

Originally Posted by JVN

You could replace heavy steel sprockets with lightweight aluminum ones.
That might save a few pounds.

Since you're pimpin your products again John, in case EO didn't call can you make sure ours get shipped tommorrow? :ahh: :eek: :D
Pete

We are under weight, but we have a very important component to add yet...

I just went through with the mill and took a couple of mounting blocks that were 17 ounces each down to about 5.03 ounces each :)

Looks like I have a lot more to do...

Ours is like 7 pounds underweight, which is good. We decided to use those spare pounds to balance out the robot and help it come off the ramp without tipping (which has happened to us twice).

Quote:

Originally Posted by JVN

You could replace heavy steel sprockets with lightweight aluminum ones.
That might save a few pounds.

Hmm... I can't imagine those being strong.

All I can think about is them getting torn to shreds in the middle of a pushing match.

Our team was able to lose 10lbs off the robot in 1 day.. BEAT THAT JENNY CRAGE!