Quite a few of the students took turns then too So a successfult test here is a closeup of it after the test
Material HIPS printed on a Chiron. .8 nozzle .88mm outside perimeter 1.36mm inside perimeters 8 perimeters .4mm layer height about 115g of plastic. So its solid.
Might test picking up 300 lbs.
We had a 3D printed hook for Power Up. When climbing the bumpers from the adjacent robot were over ours and we we lifted them too.
Our hook shattered and a piece hit our drive coach.
I can’t tell you what materials were used but it held over 240 lbs during testing.
Edit, It looks great. 
Currently we don’t have any one weighing that much. But we are using 2 hooks one on each side of the robot. We did the hanging test like that as we are not supposed to hang too much weight in barbells on it as if it breaks it might damage the floor. This hook is 24mm thick in each direction minium. We tested an 8mm round and that held at 75 lb, broke at 100 (the max we can use) . So theoretically its about 9x the plastic. So confidence is high especially with 2 hooks. We have a winch on the left and one on the right of the robot this way we can shift the center of gravity to help level the bar. Will see if we can find a 300lb dude who wants to hang from it though. And of course we will bring some backups. As we buy HIPS at about $10/kg this is a little under $1.50
Sorry yours shattered. Probably was PLA. PLA is very strong but brittle kinda like glass and one of the few filaments that will shatter. HIPS,ABS,PETG usualy will tear. Nylon will deform and stay deformed kinda like metal unless you have bad layer adhesion in which case it will tear along the layer lines. Especially CF and GF infused Nylon likes to do that as the GF and CF particles that give it the extra hardness also decrease tensile strength and layer adhesion. Now HIPS unlike ABS will give a bit before tearing so you can see it deform at about 70-80% max. If you let go it will return back to the original form Now this hook at any “test” that day did show no sign of deforming. Actually there is a mistake in the design but it won’t hurt. Based on the 8mm hook kids wanted to tripple the strength so they trippled width and thickness.
Thanks for the warning. If you could find out what material you used I’d be interested to know
Here is another pic of some current year prints shot a couple of days ago
Nice print - what material do you use? One of our past hooks was similar. We learned that if you put a hole in it for a bolt or shaft it will tear there unless you make it as wide as the other piece on each side of the hole then it will tear up top. If it broke into more than 2 pieces I would be pretty sure it was PLA
I would have to double check. Seems to me it was something like Ultum.
I’m not a print guy.
Ultem/PEI is a little out of our range both price and temperature wise as it needs to be printed in the mid to high 300s Very tough, Very hard and yes it will shatter. What kinda printer you got probably one in the range of an intamnsys like a funmat HT. We are thinking of upgrading one of ours to that temp range some day but the big problem at the moment is the cost of filament. Its 10-20x the cost of HIPS. Real nice print though
Our build space at the time was housed in a tech training center at a local Community College. We would generate CAD files and they would print parts. They have training in Wind energy, Robotics, Police, Machine shops, to name a few.
As I recall it was very expensive to print. They had told us they had one cartridge that was about to expire and it could be used.
Yes the room had to be preheated.
I do not know what printers they actually have.
We do not build there now, but we still have access to printing through mentors that work there.
Thats a great resource. PEEK is another great material in that range but even more expensive. Well one can dream. We get our entry fee paid currently by DOD-Stem. And the guy came by and say “Cool you 3D print - we 3D print too. Only we currently print in titanium” So I said “I take titanium can you print the parts for us” He just laughed. So I guess it will continue to be HIPS, ABS, PETG and the occasional Nylon. I could print POM/Delrin too but that requires a serious enclosure with some serious filtering (its on the drawing board)
Sounds like you have some great resources also.
Maybe you could print a whole robot. 
We are the pic above is the frame. We got 2 printers that we bought for about $400 each plus we converted 2 $40 food dehydrators into filament driers. and we enclosed them by draping a plastic sheet over both of them so we kinda have a slightly heated (40-50C) print chamber
Then we even printed the elevator as a test (will lift 200lb probably more
That was a bench test
The above survived and off season competition
And now we got this for the season
So now you can 3DP a robot too. We update about weekly even through build season.
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