X drive (FTC) lowrider


How long did that print take?
PLA, PETG, or something else?

Print is PETG. and its solid - that means either as many layers as it takes or 100% infill to have no air inside as close as possible to injection molding. We did not time the printing. It took as 3 weeks to cad it. The design this time is to be able to be printed on the teams printers that means a prusa MK3 I2 or an Ender 3 Pro. I would estimate the overall print time at about 48 hours. Its depending on what nozzle was used. I can tell you there is 1.48 kg of filament on this frame. With a .8 we can print 1.1 kg in 24 hours. With a .6 about 600-800 g and a .4 about 1/2 that . The big pieces can be printed with a bigger nozzle if I print it on my big printer with a .8 and a volcano hotend I probably could do it in close to 24 hours. But also we are so far about 4kg into the project because believe it or not not everything fits right the first time out… Especially in FRC and FTC… We are not sure yet if the rest will fit either - first scrimage is in december and first competition in January.

This are the first 2 stages of a 4 stage extending crane tower that will fit into the 18x18x18 cube with the frame and extend 36 inches. It uses M5 bolts as axles GT2 pulleys with bearings and GT2 timing belts and will be powered like the frame by a NeverRest gear motor. The horizontal arm with the gripper will extend too. The gt2 pulley on the bevel gear on the 5th motor of the frame will use a gt2 belt to turn the arm as in this years challenge driving will be tricky and we plan on just driving to a predetermined location and then just do pick and place with the arm

Why did you choose this orientation of the wheels as opposed to a diagonal that would create a wider wheel base?

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ease of CADing, manufacturing or layout. could be lots of things. could also be an oversight.

Pretty wicked idea. Even if it may not be optimized. What’s great about it is that they can throw another set of files in the printers and have it ready in a weekend.

you are absolutely correct about putting the wheels diagonally giving a greater wheel base and that might still happen. RN we opted to put the crane arm diagonally and the cones are only that high to grab hence the low rider approach. So for now that appeared to be the best compromise

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Exactly and as I said this is not iteration 1 sofar just the first completely finished frame that is a alpha test candidate. Between my shop and the club we have about half a dozen printers so knocking a new version out won’t take a whole weekend just the time it takes for the biggest part to print. And we are also working on a “conventional” bot so in the end the better one will go to the competition.

The X-drive bases that I have seen in the past have located the wheels at the diagonal corners (oriented at 45 degrees) rather than at the midpoint of the sides. This typically gives you a larger wheelbase for more stability.

I would call this +drive rather than X-drive…

Is there a reason you chose this configuration? I see a turntable in one corner of the drivebase and mounting points for the REV control system components, so maybe you could not package the drive motors in the traditional locations.

By the way, the printed base looks awesome. Can’t wait to see the full robot.


Its being discussed the problem atm is to fit everything with the way we want to have the crane work. I can see some solutions and am sure we get there

This prototype more “X” dirve instead of “+” drive - has wider stance while being about 1/2 inch narrower.

For those keeping track of stats. Print time for all 6 pieces with .6 nozzle total 29.5 hours. Done in less than a day on 3 printers and some pieces are in HIPS some in PETG. Reason being is one of the printers was optimized for HIPS and I wanted to compare some HIPS and PETG side by side

Cad to redesign it all involved a total of about 47 hours in F360.

We also decided to go 20:1 on the motors and use the ones with the planetary gear box on the drive and drop to 3 inch omnis. No obstacles this year and it lowers the center of gravity and should give us another inch to play with height wise and make it easier for the crane to rotate.

Well all will be proven right or wrong when its all put together and works


You may want to double-up on the omni’s with the rollers of the second wheel interspaced between the rollers of the first. The ride will be a lot smoother and your contact with the field will be better.

Yes it’s on my list thanks I just saw yesterday they line up perfectly si I will order 4 more probably next week as today I’m doing an off season event with mu Bronx team

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