We have a 95% completed robot (wooh!) but we need to weld a brace at the top of our ball hopper. We are welding AL, in two different places. The question is, do I need to dismount the section I want to weld, or can I weld it in place. The issue is what to do about the cRio. To remove the cRio is a 2 hour task. I can pull the boards from the device and disconnect the power connections.
Thanks!
Foster
We have welded on a completed robot in past years without ill effects, but you really want to make sure that the frame of the robot robot is well grounded and that the electrical system is isolated from the frame.
In spite of these precautions, there could be problems…
Eugene
Last year at competitions we welded our arm at least 3 times while on the bot. just make sure to cover everything really well and you should be fine.
With all the discussion of cRio issues, sensitivity to ESD, etc, I’d take the time to remove it. If it’s really really difficult, electrically isolate it as much as possible (disconnect all wires, grounds, etc).
Whatever else you do, make sure that the ground connection for the welder is as close to the point being welded as possible. You don’t want to clamp on one end of the frame and weld on the other end with other components in between.
I’d also consider whether or not you really need to weld these braces in place. Many times a few 1/4 inch holes and 1/4-20 fasteners with lock nuts will do wonders. Many teams compete successfully every year without welding at all.
We’re one of those “no welding” teams…but we did use some glue and the pneumatic stapler 
I’d also suggest thinking about ways to make it easier to work on the electronics. I doubt you’ll get two hours of time outs between elimination rounds, if something breaks and you have to replace it…
Don’t do it.
I lit our IFI robot controller on fire in '07. I melted a lot of the plastic… Amazingly, it still worked.
If it is too much work to weld. Why not pop-rivet or bolt on the brace?
If you can remove it fast. Go for it.
Last week I welded two differnet times on our robot and nothing happened. We had all the electorics on a piece of plexiglass which was bolted to our frame and nothing happened at all. All I did for saftey was cover all electorics with a welding coat so no sparks or platter could get at it.
We watched a team run out of time during the finals because they had welded parts in place that couldn’t be cut out.
The requirements for our team is to be able to remove any part within 5 minutes. Right now I believe the entire electrical system can be removed with bolts and taken right off the robot- all the quick disconnects just dangle when done.
If I were you and was concerned I’d remove the electrical systems from the robot prior to welding. Unless you have money to burn…
Good luck!
Thanks to all that responded.
I took the responses from last night and from another team (thanks Dave) [take the battery out, take the boards out from the cRio, make sure that only the zone you will weld is exposed-physically protect everything else, keep welder connections close to the weld site] and we welded our support on at 10 AM this morning. Everything worked out well, all in all a 10 minute project.
DEWBot-5 is very compact. Things that may break and need to be changed out are on the outside where they have good access. Things that have low probability of breaking (like the cRio chassis) are in the center. Likewise things that have a good chance of breaking and need repair / replacement are held on with bolts.
Battery swap takes ~30 seconds, we can remove / replace the bumpers in less than two minutes to get full access to the drive train. Adjustments to the drive train is via access holes in the frame, the T-Handle is our friend, so the bumpers don’t need to come off for minor changes.
But, welding is a skill that we wanted to have in-house to allow some design and fabrication flexibility. We have a 85% welded frame with 80/20 at the key points, ones that have components that may need to come on and off. The frame is strong and light while being versatile. Our moon-rock tower is also welded, but can be repaired / modified with bolts and some pre-tapped components.
Electronics use the remaining available space (come see us at Chesapeake to see how we fit 10 cubic feet of electronics in a 5 cu ft space). But there will be a spare spike and a spare Jaguar mounted for easy swap in case of damage. Electronics can be changed with some difficulty, but again in the order of probability of happening. We have a second cRio mounted on a debug board designed by our programming / electrical mentor. It allows us to work on the programming while the build team has the robot. We can swap cards out of it and into the robot if they get damaged, takes about 5 minutes.
Thanks again to all that responded and I will take the comments back to our team.
Foster, I noticed in your post:
“FTC #8182” and rookie year “1900”. ??? 