How to Design and 3D Print an RC Racing Buggy

If you're into RC cars, trucks or buggies and would like to design and 3D print your own customized model, here's an easy way to do it.

List of tools and items used:

- FS Racing 30CC 1/5th Petrol Radio Controlled Buggy - 2.4Ghz (bought online)

- 3D modeling tool, VECTARY (online, browser-based)

- Zortrax M200 3D printer

- smartphone with 3D scanner app

- caliper

- ABS grey or Z-ULTRAT filament

- base color

- color spray

- instant adhesive - (can be Super Glue) / epoxide

- P800 sandpaper

- alcohol or suds for surface preparation/cleaning before painting

I recommend that you never skip this step when designing something. And you don't need to be a pro designer to draw some basic shapes. It's a super practical step which helps you figure out at least the basic idea of how your model should like. This way you’ll be able to quickly evaluate any layout choices later on when you 3D model it.

I didn't start the project from scratch (maybe the next one) so I needed a solid base for the new buggy design. For that I ordered an FS Racing Petrol Radio Controlled Buggy and removed almost all of its original body. I kept only the functional parts on. I then scanned the bare chassis with a smartphone so I can later import it to the 3D modeling tool.

I measured the whole chassis, from the wheelbase to all the handles of the cabin. I had to do this because the quality of the scanned model was not good enough to allow me to work with details.

I measured mainly the part of the bracket where the wheel drive shaft has the shape of a hexagon (classic matrix). It is necessary to copy that because it’s going to influence the transmission of the driving force to the wheels. You can use a caliper to make your measurements easier.

I imported the scanned model into VECTARY, a free, online 3D modeling tool. I designed the wheel thread using a parametric plugin called “Wheels”. I just dragged the height, chose the number of rays I wanted to have on the disk (5 are in my opinion the most dynamic) and when I was satisfied with the proportion of the wheel, I baked it.

You can also use plugins like Joints & Wires (great for creating skeletons bigger than your 3D printer), Mirroring (a symmetry tool which mirrors the object you create), Revolve or Array (duplicate and edit objects on all axes) to speed up your design time.

Important: Make sure you add enough thickness to all the bits and parts where there is a high physical burden like the wheels or the handles on the skeleton.

You can add in the 3D modeling editor little pins and holes to all the small parts that you want to print. This will make it a lot easier for you to combine and interlock them after printing, and, in my case, it helped keep the buggy together. I exported them as *.obj, because it works with most 3D printers available on the market.

I printed the buggy skeleton and the wheels on a Zortrax M200 3D printer. Since this 3D printer is limited to printing a certain size (200 x 200 mm), I had to cut the models into smaller parts.

Zortrax M200 lets you use all kinds of thermoplastic materials such as the Z-ABS, Z-ULTRAT, Z-GLASS, HIPS, etc. For higher material pressure, the manufacturer recommends using the Z-ULTRAT - it is stronger, but also more expensive and therefore harder to sand. You can use the ABS though - it is cohesive enough to do the job.

OK, now prepare to get your hands dirty! Models coming out of a 3D printer don’t have a smooth surface. You must sand them with conventional sandpaper. For uneven surfaces, use abrasive papers marked P100, P120, P180. They sand the material much faster, but they don’t smooth the surface completely.

For better smoothing, you can use sanding papers with grades of P400, P500, P 800 and above. For this buggy I used the P800. Re-sand with P800 sandpaper at least twice, and preferably under water. Leave it to dry and clean with soap water to get rid of any dust before spraying. I sprayed the redesigned buggy with three layers of white color and attached it to the original buggy chassis.

What’s the point of making an RC buggy if you can’t take it for a ride, right? The buggy’s first test drive was in my building’s hallway. I was surprised how well it handled so I’d like to take it out on a dirt track as soon as the weather allows it.