It looks robust enough to survive, but with some notes:
You don’t want to have a low infill near the bolted connections, as the bolts will crush the plastic. If you have a way to print it with full fill around every bolt hole then it should mitigate this.
This design still needs an accurate bearing hole in the frame rail to support the axle near the wheel, but depending on your machining resources this might be hard to do. Additionally, the bearing hole in the 3d printed bracket mounted to the frame has to be coaxial with the frame bearing hole. It looks like the bearing in the 3d printed bracket will poke out enough to center the gearbox on a bearing hole in the frame. Do you have the ability to machine this? (A drill press and an appropriately sized step drill bit or reamer should do)
Be mindful of the axle deflection near the encoder mount. 3d printed parts are way less rigid than aluminum, and if the encoder is not concentric with the axle it could be damaged. A flexible connection between the encoder shaft and axle would be a good idea.
What did you print it out of? and how many perimeters/ walls - that is even more important than infill especially around bolt holes and axle holes. Each material has its pros and cons. PLA is pretty strong but also very brittle so don’t hit it with a hammer or have anything high impact happen. It also when not annealed will start to deform somewhere between 50 and 60 C so don’t leave it in a hot car. For gears its ok for low speeds. Be aware that due to its hardness at high speeds - even lubricated - it will have some abrasion so you will create a lot of dust that then will cause more abrasion and more dust etc. Only material I’d suggest for gears - especially on something like a CIM - is Nylon something. I also hope you got the Hex adapter for the cim as no plastic will “hold” that tiny key for any kind of torque. We are printing planetary gearboxes for a similar setup you can check it out here
I wasn’t planning on using 3d printed gears, this design uses a lot of parts from a toughbox mini. I did print on with 2 perimeters in pla and it seem rock solid.
its rock solid to look at. If you use it it will disintegrate. PLA is like glass very hard and solid but brittle so don’t hit it with anything. It is the perfect material for models or picture frames etc. If you want to use it structurally you have to anneal it and print it solid with 6 perimeters or more. If you anneal it it will change dimensions unless you keep it from doing so with a mold - I will probably post a video on how to anneal PLA in my youtube channel in the near future
I would avoid using a printer. It is a pain to try and use printed parts because there is a lack of strength in one direction, leading to a potential breakage. Also all holes have to be drilled out (even at very low speeds) because the printer is not perfect.
We have used PLA 3d printed parts as structural pieces in the past without any annealing. If they are designed properly and used in the right application they work just fine. This gearbox looks like something that would work to me. Most of the high stress loads would be handled by the bearing holes in the frame rail.
Another way to size the holes correctly is to make test prints and vary the hole dimensions until you find the setting that works right for your printer. We do this for our bolt/rivet holes and it is repeatable. It’s a good idea to measure your printed parts with calipers often to make sure that they are coming out within the dimensions you want.
We have used PLA too but have stopped for the most part except low stress application. Why use it if ABS, PETG and Nylon work so much better for most mechanical applications. As for the lesser strength in “one direction” also called layer adhesion its true but with the right settings you can get at least 60% of the strength than in the “other” direction so you can design for it. We just started today to put a “skateboard” about 32x30 in together completely out of plastic (except the nuts and bolts and bearing balls) Will probably post a video on this on my youtube channel after I am done with the Planetary gearbox videos (that will most likely replace the tough boxes minis) and those planetary gearboxes are all 3d printed.
This channel will chronicle our attempt to turn filament into an FRC robot