Getting into FTC (came from FRC which I still do) And while we are working on the conventual stuff I am investigating on how/what to print for FTC. The test stuff I am working on is done in PETG and designed to be able to be printed on a 200x200 bed or larger.
Here are some examples in the works. Goal is to 3DP as much as possible and if it works (beats the standard kit bot) it will show up in competition. Motors are mostly Neverrests (one uses what one got). Printers used are a Ender 3 Pro - stock, Anycubic Predator with a volcano and Anycubic Chiron with a volcano. So all subs $500 printers. Some parts might have to be printed in other materials but not yet. To design the stuff we use F360 - why? Cause it has been used and everyone kinda knows it.
1.) elevator - extending arm - 50 % finished - 4 stages. Powered by Neverrest 20 or 40 with GT2 belts and pulleys. The hope is to make it lighter and more accurate .
printed in <200mm sections to fit an ender volume - this particular one is printed on the predator
with 1 extension in place wheels in the rails ar 625 bearings. bottom will be mounded on a 3 in lazy susan and rotated with a neverrest motor mounted underneath via GT2 belts
2.) Small involute bevel gears to allow motor to be mounted on a 90
Final ones will be larger I assume Here is a big one I used in FRC
3.) X-Drive Chassis - hope is it should help with driving this year as it should do well (at least so far on paper) to do all the 90 deg. turns in this years maze.
So far 2 of the omnis mounted and the 2 cradles for the control and expansion hub laying down. The rest is being worked on
Using gobuilda 96mm omni wheels with a custom hub (yes I know there are hubs available but question is how well do 3dp mounts stand up to the task and a drive wheel makes a good test subject) The D cutout for th D shaft is a snug fit and then there are inserts for M3 square nuts (square captive nuts work better on M3 than Hex in plastic.) RN I got regular M3 screws as “Set Screw” until I go get my M3x10 ones. The square nuts take the torque.
As aluminum support we use 1/2 in 16 gauge square tubing with 6mm PETG or HIPS solid backing - pretty sure overkill as it will survive FRC style collisions of a 125 lb robot at full speed. But as its lighter than the conventional frame we go for now with that and can make it lighter once all other stuff is straightened out. All frame parts so far will fit on an ender 3 build plate - biggest one is the “X” in the middle that is 190x190. I also know there are mounting plates for the motors existing - but then this is a 3DP investigation. Thinnest wall on the frame is 5mm
As for PETG prior tests have shown that under a static test load a 50mm2 cross section piece will yield and fail between 170 to 250 lb depending on the way its printed (orientation, ambient, nozzle temp etc)