We are going to use some of our filament to print a community outreach bot. Also something to use the CIMs for as everything seems to be going NEO. The robot will also be a test platform to try things out. Heck the whole design method is an experiment. Here are some details.
The robot body will be an octagonal Pyramid With the top cut off the bottom diameter about 26-28 in with an about 1 in TPU bumper (its not going to run into other robots just maybe an occasional wall due to operator error.) The Top will Be about 12 in in diameter the body will be about 4 foot tall - on top there will be an about 1 foot Viking head with helmet etc. The construction will be 3DP with Styrofoam reinforce/wrapped into Fiberglass. So there is an experiment with a composite robot. The drive base is designed to take multiple drive options so we can experiment here is the plastic frame (picture of the cad we just started printing on only 1 printer so it will take a couple of days to complete as the other printers are getting some TLC currently
So this frame is 660 mm diameter. The big hole that looks like an Arrow will get 3/4 in Styrofoam the others are for the wheels and gearbox assemblies The first drive will be very simple Center drive tank so the 2 outside wheel bays in the center will get the wheels with motor then you have a front and rear wheel that will be omni with a skid plate on the side in case the robot spins and the omni would hit a lets say 1 in something sideways . We opted for this setup to allow easy turning in very tight spots so the robot can do a 360 without leaving its body perimeter. You can see the drive could also be configured with X drive or even some steering. maybe even a swerve. This bottom part will also hold the battery and some of the electronics.
The top level will have 2 motors that power the arms and one that turns the head. All in all we are shooting for a humanoid looking robot. Electronically we probably start with a cheap RC unit and some home cooked electronics. Maybe later we go stick a PI in it or if FIRST chucks the roborio one of those.
Well we cant print a 660x660 frame so we had to cut it in 4 and have to print 4 pieces each is an about 10 hour print and we are trying to do it in ABS this time.
As we move along files are here
So feel free to make one too. Of course the bot as it is a viking - will carry a shield that will look something like this
Only as big as will fit on the printer.
Octagonal drivebase…sounds familiar.
Hope this project goes well!
Thanks - It won out over circular
First section (of 4) of the bottom frame / drive base printed
Zyltech ABS About 450 gram
Its sitting on a piece of foam I am preparing for a core construction test . It is a piece of 1/4 inch foam covered in window screening held on with latex paint. 2 of them with the screens on both sides and the middle (or a 3/4in piece of foam) make the 17mm that floor of the frame needs. The foam can be pre prepared in 2x4 sheets which can be done legally any time as it falls within the time and "A student can do with hand tools (brush) limits. IDK if the time the paint takes to dry will make that illegal. An other option - as this foam is covered is to use formula 77 spray glue which is faster - but a bit more expensive. and it dries pretty fast too. Now that in itself makes pretty strong panels the 1/4 in sandwich will flex more and seems to take more of an impact the 3/4 in is much stiffer. the thicker the foam the stiffer as the FG screen on the outside would have to stretch more and FG does not do that too much.
For much more strength you then can lay some cloth an either epoxy or polyethylene resin on it. Usually polyethylene which is boat resin and much cheaper will “Eat” foam but the usually 3 layers of paint I put on protect it well enough so it does not. Its super light and strong enough for a lot of things - maybe even a drive base
Update - all pieces for the bottom drive train frame printed and ready to be glued (ABS welded) and having Styrofoam and Fiberglass applied
and the final product should be looking something like this - this is a rough outline like the head will not be a free floating ball lol etc
Could you provide a little more detail? Are you epoxy/fiberglassing the individual pieces of ABS? or just the shell that is going to attach to them? Close up photo of process may help. Awesome job btw! Looking forward to seeing the process and progress.
It is going to be an experiment in multiple things. It is supposed to show how different technologies behave. We prepared some composites out of foam and fiberglass window screen and Latex paint - something even kids can do safely without any major safety precaution in their garage/back porch etc as we are all remote
This is a 2x2 foot sample test piece of Styrofoam house siding paneling first coated in Latex paint then some window screen cut and applied to both sides and a couple more coats applied that makes a pretty stiff panel already. We are going to glue 2 of those together and have about a 3/4 inch very strong panel. You can also use some elmers and packing paper and have a flat surface to paint - there are a lot of options
Here is a (poorly cut) piece of 3/4 in garage door insulation foam prepared in a similar fashion and then glued into a about 6 in diameter hole of a failed print for test purposes with gorilla glue and covered in a piece of window screening that was affixed with some formula 77 spray glue. Now that already you can hit with a hammer. Now the Latex paint - besides holding on (glueing) the window screen to the SF also protects it from the resin if you use some (Polyethylene resin is cheap but eats unprotected Styrofoam) So on the drive base where strong is important we go and then cover it with 8 or 10oz cloth and Boat resin. The 3d printed plastic is to provide the base shape and make sure the holes are where they are supposed to be with all other things like we dont want anything protruding on the bottom so the bolts are countersunk etc. So you marry the accuracy for 3DP with the strength of Foamcore FG tech In some cases the Foam/paint/window screen should be strong enough. In some cases some extra layers of cloth/mat/woven roving etc might prove necessary.
It is an exercise to hopefully in the future build strong light weight robots. This 26in diameter drive base which is close to a competition bot at 30x30 thereabouts. will come in for a stiff frame at about 5 lb. 3.2 lb of plastic and the rest foam/window screen/glass/paint/resin
The shell right now is intended to be made of 1/4 in foam with a window screen/paint base and some cloth/resin on top of it. And the paint/screen make a good base for the resin to hold on to. The top then will be painted with automotive paint - Its basically the same tech as if you fix a rust hole on your car. Put some screen on - in this case FG and some FG over it and then paint it all. The foam/3DP is there to give it shape and thickness as FG does not like to stretch so the thicker the stiffer the panel. Now finishing this project is dependent on a lot of things as atm - for many reasons - mostly caused by Covid - team 1989 struggles a bit to survive all together (No support from school, teachers took leave of absence/retired/are incredibly busy, sponsor say "ask after the pandemic business is down, school open/close/open/close/ hybrid/remote etc etc.) So right now its happening in everyone’s garage/porch/bedroom and on discord etc
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