Anyone ever tried it? I am in the middle of a quest to “marry” 3DP to some Fiberglass techniques. As one can always add weight to a robot for now I am seeing how light and inexpensive I can build one. (got to do something covid and retirement has stranded me with too much time and I hit a wall on some of my math projects besides I got to keep some kids busy remotely).
So right now I am leaning towards using 3DP for making a template then filling the holes with XPS (Styrofoam I got some and that stuff is cheap) seal it with latex paint and then glass over it. Make wood inserts for where the bolts go kinda like building a surf board or a boat.
If there is interest I intent to report when we get something done. As for the cost - how should I count cost. Like we will use quite a few of the “standard” FRC parts like CIMs and roborio and motor controllers etc. So do I list them separately especially as those are not new and do I count the credit you get for opting out of the drive base as a negative (Frame/drive train and all structural will be 3dp/foam/glass/wood composite.
So goal is to see if we can do it without metal with the exception of fasteners and axles and bearings but the goal is (if tests pan out) to replace everything or at least see if it can be done. As of today the plan is to stick a 3DP planetary inside a 6 in wheel and put the motor at a 90 with a 2ish to 1 reduction on a bevel gear (to save space) Using Nylon/With FG as a rim for the wheel and a TPU tire. and right now make it front and rear steer with a rack and pinion - just to save 2 motors instead of going all swerve plus the 6 in wheels should make it easier over obstacles. than using the small wheels and getting a 40ish to 1 or so - or 2 of them for the climber also 3dp also driven by a CIM. etc.
Right now we have some paper and pencils/pens and some inventor sketches invested in that and used up some packaging Styrofoam and a little bit of FG stuff and some failed prints that were glassed over to get some ideas on different techniques and different materials and we learned some things like don’t use thin PLA with Polyethylene resin as that sometimes gets warm when curing and PLA deforms when it hits 40 C. So we intent to go to our “old staples” ABS, HIPS and Nylon for the gears.
We are crazy - right? We are also looking fwd to the inspector - somewhen in the future looking for a piece of metal to see if there is a short between ground and the frame - lol. Goal is to do the whole robot for less then the credit for the drive base or come as close as possible.
I would recommend doing a full BOM, if this is for educational purposes. Perhaps have an extra column where you can indicate if something is KOP or not.
The AndyMark voucher for opting out of the kitbot can only be deducted for items purchased with the voucher itself. For these purposes, since it’s not actually a competition robot, I’d say any products you could have gotten with the voucher, if you weren’t just using old stuff.
One thing to consider. Machining faberglass creates fine particles that can be hazardous when breathed. Without having proper ventilation and masks (lol, right?) for everyone at an event, working on such a robot could be challenging. The same goes for carbon fiber and lead, when used.
There have been plenty of cases of teams building entire robots out of wood (exceptions being axles, motors, gears, etc). 1771 and 4183 come to mind off the top of my head.
There have also been robots made primarily of polycarbonate sheet and tube. I don’t remember team numbers or years off the top of my head, but if you search you should find it. And IIRC one of the Ri3D teams last year made their robot from polycarb.
As to whether or not you’re crazy, I know from previous discussions of similar matters you guys prefer the cool factor over a competitive advantage. If your goal is to field the most competitive robot, I’d always recommend sticking with the most basic, reliable, quick to build, tried and true drivetrain. Having a drivetrain that’s 10% faster, lighter, or cheaper won’t win you any matches, but if it breaks at an inopportune time it can certainly lose you many matches. If you can have your drivetrain assembled a few days after kickoff, that gives you a lot of time for driver practice and the whole rest of the season to work on mechanisms that will actually score you points.
On the other hand, if you want to explore this for cool points then yeah go ahead.
Yeah I am aware of that and am working on some things to minimize that. During construction the intent is to not really machine. The idea is to pre drill the holes into the wood blocks and/or 3D Print them in the plastic and then glass over them and then you just wait a tiny bit to when it starts setting up and is still very tacky but set up enough to not move around no more and cut the holes out with a knife you can even put some masking tape over it and you get as much in particles or less as when cutting the cloth this was done on theses holes
The thing we learned from this part is that you need thickness to get stiffness the bottom which has 5mm spacers in it was pretty stiff while the plate with the holes was about as flexible as a FG fishing rod. here is another shot of the “stiff” part
It all started out as a 1mm wall thickness 3DP part (printed with a .8 nozzle. The holes cut with the knife are not that nice so currently we are making them bigger and then “plug” them with a properly sized plug or if its wood use one of the inserts that are used in the bumpers. On foam Polyurathene Floor covering works nice but unfortunately does not stick well enough to ABS/HIPS/PETG etc so now we are also testing latex. Now that works well with FG screen which might be strong enough for things inside the robot like a battery box or a shooter or ball pickup/conveyor etc future tests will show in which case at any time it could be cut with a box cutter. if absolutely necessary. The drive base will have some woven roving or 8-10oz cloth and resin. In the picture on top you see that the holes are evenly spaced and our current system works on that. so the plan here is that everyting that mounts to the frame is based on those hole spacings so that in the pits hopefully there is no machining and cutting - maybe some gluing if something breaks.
Well atm in the development stage and it would not be the first time something gets put back on the shelf to maybe get revisited at a later date
That is why it is an off season project and might never see competition or not for who knows how long. This years robot we had together faster than any year before (except maybe areal assist but thats a close one) And having the system where everything is based on the same hole pattern really paid off as we could just take something designed - whenever - and make and fit it. This year we used toughbox minis for gear boxes with mounts that fit the system that where designed off season and we intend to keep going this direction at least for now
Yes - cardbpard was discussed but for now foam/3dp chosen. But there are tests of using cardboard too cause would be nice to reuse all the boxes stuff gets shipped in.
Our 2011 drive base was laser cut wood and the superstructure was made from honeycomb fiberglass panels we got from one of our sponsors who made airplane interiors.
One of my favorite bots we ever made.
We generally use wood (plywood dieboard) somewhere on our robot every year.
In 2017 we made a prototype climber out of plywood. It worked so well we never switched to the waterjet cut aluminum one we made.
Kinda reminds me of the 2009 or 10 robot we ran out of aluminum and finished it out of 2x4 was an ugly robot and we did not do too well but we scored some points. We for a while had a belt made from Duct Tape ever since we have a tradition that “The robot isn’t finished until there is some duct tape on it” I think its time to kick that “tradition”
Our 2009 robot was mostly plywood, and it did real well in Arizona. Plywood is a natural composite. it’s easier to work with that fiberglass. And not seriously expensive,
Yes that is an option. But it has one big drawback in my opinion. See except the 3D Printers we are a hand tool shop due to finances. The Metal bots we did before were usually the cut up bot from the year before with things added and there was no 90 on it and the robots were built as we go along with hand tools and the closest I have ever seen that resembled us was the TV show “Junkyard wars” Where our robotics room was the Junk yard. Some years we really stunk and I felt sorry for everyone who got us as team mates and some years we rocked anyway qualified for Nationals 2x if I remember correctly did not go once cause of $$ and went to regionals quite a few times but our robots were always - ugly. One years they gave us the McGuyver award (some judge crossed out whatever award was on the paper and wrote McGuyver on it. Now if we go plywood we are going to cut it like our bumpers with a hand saw or maybe the sawsall and most will be eyeballed. With The 3DP (we got 2 printers we bought for $300 and $400 respectively and I got my printers) the kids design in inventor and this years robot (the one we did not get to compete with) was the best looking one we ever did - all 4 wheels are touching the ground without someone hitting the frame with a sledge hammer or stepping on it. Which was the habit as we knew we can slap a frame together out of last years frame with some pieces of aluminum filling in the holes and take the credit. Now we did the 2020 robot out of 14 kg or so of HIPS that we buy for $4- $10/kg and IDK about $25 worth of of 1/2 in tubing. There were some people who suggested a team with our recurring funding problems should not exist but our District used to send 1 kid every 5-10 years to an ivy league and in the decade or so I have been doing it team 1989 has sent at least 1 kid to an ivy league a year. I see some value in eyeballing and McGuyvering things and its a great skill to have during a competition but it really hurts me to start the robot like that I like to see some math applied and some Cad drawings and electrical diagrams etc. And I want if we decide on a square frame all sides to be the same length and the corners be a 90. I don’t care too much if the kids decide on Mecanum or WCD or whatever drive as long as all wheels that are supposed to touch the ground do so. So Hence we will continue to use 3DP as with that at least the holes are pretty dead on - well within the tolerances of the printer which beets a hand drill any day especially when wielded by a teenager. Now even though we tested a prototype of our robot in some off season events we found some weakness and potential areas of failure in the 3DP and some did crack even though crazy glue took care of that quickly and some duct tape reinforced it. So the idea came to use FG instead of Duct tape from the start and maybe use less 3DP plastic (as that takes a lot of time to print) and more FG. Which then made it apparent to us that just FG is very flexible but if you give it some bulk it becomes quite stiff so hence a foam core and preferably one that that has good resistance to compression (XPS like its used in surf boards) We tried to glass Cardboard and even though you can use all kinds of things as a resin the cardboard has the problem that it easily collapses under the FG which doesn’t make it that stiff unless you use quite a bit of it. The problem with foam until now was that Polyethylene “eats” eat so we bulked up with the 3dP plastic. Now we saw some youtube videos that you can seal the XPS with latex paint and then glass over it. You could use epoxy but that is quite expensive and we have not tried that yet so we use marine glass and epoxy for the parts that need to be real strong. Plywood ? I don’t see us cutting anything straight out of a 4x8 sheet with a sawsall. So we give this a try - if not we use the system we used to build the 2020 bot out of until we find a better solution to move ahead. And we are going to share quite openly. I know there are a lot of teams out there that have all kinds of budget and what we do is going to be of not much use but I know there are teams out there who are kinda like us and maybe we can keep some (including us) alive. FRC robotics has not only the hardest fun you ever have but it has made/saved a lot of our kids quite some $$ when it comes to college and last year for example 3/4 of our kids about were on free/reduced lunch - thats one reason why I am still at it
This is something we are working on - we definitely won’t glass in the pits so other things will have to be used. as we have by design bolt holes ever so often a break that can’t be fixed with glue could be patched in the pits with anything bolted to a hole before and after the break at least at the superstructure and 3DP parts well we will have spares we had every 3DP part used on the robot as a spare and some more than once. And I know as stated above teems have used FG and CF etc before - mostly bought panels or rods and I know some 3DP parts with chopped FG or CF and that also could release all kinds of particles if you machine (drill/cut) it. Yes safety is very much a concern but that it is with everything
This is not a major issue with most non-abrasive machining of these materials. Most of the particles are large and not respirable. While I grant that there might always be a potential oddball substance that is particularly harmful (hypothetically, maybe you conjured up an asbestos-filled board that has unconventional properties), this doesn’t appear to be especially risky as a general practice. Filtration masks and safety glasses for the tool operators seem like reasonable precautions, but this shouldn’t be a risk to those outside the immediate vicinity. (Maybe approach your neighbours in the pits to explain what you’re about to do, and see if they are concerned.)
With abrasive machining, suction from a vacuum cleaner (with a HEPA filter) and dust abatement (using a lubricant) can potentially keep the fine dust to a manageable level, though it’s hard to be sure about every possible material, every possible process and every possible environment. This is probably best avoided at a competition, but can nevertheless be accomplished safely in many circumstances.
Lead is a very different kind of hazard: mainly, don’t ingest it where it can be metabolized, but mere contact is not itself consequential. Wash it off of yourself, your surroundings and your tools immediately (or confine it to a disposable surface or container). It’s virtually inconceivable that you would need to create respirable lead dust (why are you sanding something made out of or coated with significant amounts of lead?), so that is not a hazard worth systematically mitigating against in FRC. (File it alongside bear attacks.) Lead fume is generally not present in soldering: most of the smoke is from the rosin flux, which is much more acutely harmful.
