Materials and 3D Printing?

[sciencecat42]

What materials is everyone building their cars out of? Currently I'm are using thick balsa/bass sticks or sheets, but I'm considering using metal or even 3D printing the whole body since I can never get the car to go perfectly straight.

[Things2do]

I use small poplar boards and brass axles and rod with a threaded rod for the {currently for looks only} wingnut brake. I've heard of 3-D printing a car body, but I would personally print a model first to make sure it would work properly and everything is properly aligned... Although I don't have a 3-D printer or know how to use one...

[PM2017]

3d printing connectors, using cf rods to construct the chassis.

[JojoCho]

3D printing isn't that bad once you practice and print with it a bit. Amazon has some printers that are around $300 if you're willing to spend a bit (300 is actually very good for a printer). The one I have was around 300 and since MTV doesn't require large pieces, having this printer is very convenient

[cuber]

3d printing connectors, using cf rods to construct the chassis.

Same, except I use 10mm aluminum extrusions. Still light, but even stiffer. I use PLA for the connectors, I could go stronger but i’ve found the stiffness of PLA is more desireable than toughness.

Side note: we have the same event roster this year

[PM2017]

3d printing connectors, using cf rods to construct the chassis.

Same, except I use 10mm aluminum extrusions. Still light, but even stiffer. I use PLA for the connectors, I could go stronger but i’ve found the stiffness of PLA is more desireable than toughness.

Side note: we have the same event roster this year

That's interesting. Was wondering just a few days ago if anyone had the same event schedule as me. Frankly, it's a rather strange assortment.

My parts are printed using MatterHackers Black PLA, on the Prusa i3 mk2 (our team's), and the Creality CR-10s (I bought this one myself ).
I tried using PETG a bit last year, bit switched back because I decided I didn't have time to dial in the settings. For some reason, I never got back to the PETG. I might actually try that sometime this week...

3D printing isn't that bad once you practice and print with it a bit. Amazon has some printers that are around $300 if you're willing to spend a bit (300 is actually very good for a printer). The one I have was around 300 and since MTV doesn't require large pieces, having this printer is very convenient

Adding to your point:
I highly recommend a printer from the Creality CR-10 series. I picked mine up for about $450ish. It's absolutely massive, but I end up using the same 4 inches by 4-inch square for at least 90% of my prints (in comparison, the print dimensions are approximately 11.8in (x) * 11.8in (y) * 15.7in (z)). You could probably use a Creality Ender 3, but I can't attest to its quality since I have no first hand experience with it. Still, I'm extremely happy with the way it works even with my small print size.

Also, there's a huge community around the Creality CR-10 series, so if something goes wrong, you have a very good source of info to fall back on. (Two weeks ago, I managed to mess up a print, and a bunch of filament deposited into a blob around the nozzle. I removed it, but it took the insulating tape with it. I had no idea what to do, but within ten minutes of asking for help on a facebook Creality CR-10 group, I had five responses from experienced users.) One weird quirk, however, is that Creality doesn't sell directly. You have to buy it through some other company, which means no customer support from the company,

If you have a larger budget, however, the Prusa i3 mk3 (or the earlier version, the Prusa i3 mk2) is a very good investment as well. The quality of the prints, (and, tbh the printer) is much better. We bought ours just after the mk3 was released since the mk2 price subsequently dropped. I haven't really checked to see if there is a community around the Prusa printers (though I'm sure there is) since I haven't needed anything.

Obviously, you have to do lots and lots of research before you buy a 3d printer, but it is a solid investment. You'll learn a lot; I know I did. Also, they make life easier (at least when it comes to designing things. It freed me from the constraint of items I could make using wood, thin aluminum, a Dremel, and a drill.)

My biggest source of information was Youtube -- especially channels like 3d Printing Nerd, Maker's Muse, Thomas Sanladerer, and CNC Kitchen. I also looked up things like "Best 3d printers under $500 2017."

[cuber]

If you have a larger budget, however, the Prusa i3 mk3 (or the earlier version, the Prusa i3 mk2) is a very good investment as well. The quality of the prints, (and, tbh the printer) is much better. We bought ours just after the mk3 was released since the mk2 price subsequently dropped. I haven't really checked to see if there is a community around the Prusa printers (though I'm sure there is) since I haven't needed anything.

+1 for Prusas in an educational environment. Our team got 2 MK2’s two years ago, and it was a blast assembling them together on the off season. For one, Prusa accepted a school purchase order, something that a Chinese manufacturer wont. Also, they just hit that sweet spot between quality, reliability, and price. You’ll find that for some schools, 700$ isn’t incredibly dear especially if its going towards something that they can advertise as a direct improvement towards the learning environment.

As an aside, A 3d printer is a luxury and not a necessity, and can sometimes make your engineering lazy. Just because your school really cant afford one shouldn’t be a roadblock. It is just one means to an end.

[sciencecat42]

3d printing connectors, using cf rods to construct the chassis.

Same, except I use 10mm aluminum extrusions. Still light, but even stiffer. I use PLA for the connectors, I could go stronger but i’ve found the stiffness of PLA is more desireable than toughness.

Side note: we have the same event roster this year

How would you attach bearings to the extrusions? Also, wouldn't that be heavy compared to just printing the sides?

[bernard]

3d printing connectors, using cf rods to construct the chassis.

Same, except I use 10mm aluminum extrusions. Still light, but even stiffer. I use PLA for the connectors, I could go stronger but i’ve found the stiffness of PLA is more desireable than toughness.

Side note: we have the same event roster this year :D

How would you attach bearings to the extrusions? Also, wouldn't that be heavy compared to just printing the sides?

You could use flanged bearings fixed with adhesive (epoxy) to the rim of holes drilled in the aluminum.

[sciencecat42]

Same, except I use 10mm aluminum extrusions. Still light, but even stiffer. I use PLA for the connectors, I could go stronger but i’ve found the stiffness of PLA is more desireable than toughness.

Side note: we have the same event roster this year

How would you attach bearings to the extrusions? Also, wouldn't that be heavy compared to just printing the sides?

You could use flanged bearings fixed with adhesive (epoxy) to the rim of holes drilled in the aluminum.

Why not just normal bearings friction fit into the drilled holes? Not sure if this could be done with the carbon fiber rods though.