Starting in April 2025, I spent some time building a remotely operated tracked vehicle. The goal of the project was mostly silly: I wanted to have fun driving a little tracked vehicle around.

The vehicle is entirely 3D printed with the exception of the COTS components like motors, sensors, and gears in the custom gearbox I built for the tank. The main chassis is printed in segments which are aligned using dowel pins before being permanently adhered to other chassis segments.

Tank

The result was a rather capable little machine!

Specs

  • 400mm long x 350mm wide remotely operated tracked vehicle
  • 25mph top speed
  • Onboard 4k FPV system (DJI o4p)
  • 3-axis gimbal for the FPV unit (GM3)
  • 11,000mAH 3S batteries, run time over 50 minutes

Build Highlights

The tank track link was the main driving component for the entire design. Because I was constraining myself to 3D printing, I made the decision that I needed each track link to be usable immediately after removing the print from the print bed. This meant no rework: No removing support material, no drilling, and no part cleanup allowed.

I went through seven iterations of the track link before settling on the final design, printed from 95A TPU. Each track link features a centering rib to keep the tracks from walking sideways off the tank, and rotates about M2.5 screws rescued from a scrap bin at some point in the past.

Replicator Mode

Because of my requirement that track links needed to be immediately useful out of the printer, a significant portion of the early steps in this project were based around tuning the printer to unlock what I’m calling Replicator Mode. Replicator mode sets the printer up to auto-eject parts after printing through the following routine:

  1. Part prints, then in the slicer we modify the end gcode:
  2. Move to a safe position, all fans to max
  3. Wait until the print bed cools to a tested temperature with easier part disbonding
  4. Drop the bed down against a piece of wood that flexes the metal print bed, popping the prints mostly free from the bed
  5. Bring the print bed back to top height
  6. Sweep the printed part off the bed using the print head

This routine doesn’t work all parts, but for smaller parts that have minimal bed contact it works really well. This let me skip supervising and removing prints from the printer for more than a day at a time, allowing me to iterate more easily on the track link design.

When each set of tracks needs 180 links, this type of work pays off in significantly easier production of the links.

Chassis

The chassis is comprised of nine major components, assembled with dowel pins and adhesives.

Chassis

It’s printed from PETG-CF. I modeled it to minimize supports, so most of it has no support material needed when printing the frame.

Complete Chassis

Gimbal

When driving the tank, I needed a way to turn the camera as the tank turned, or to manually turn the camera to clear corners when driving slowly and precisely. I elected to outsource this, and set up a 3 axis gimbal intended for a drone:

Camera Gimbal

No system is complete without googley eyes, so those were added via a small 3D printed camera bezel.

Closing Thoughts

I’ve driven this tank a lot now, and have upgraded every reliability issue I’ve encountered. If I were to do it again, I’d make a few changes. I’d make the whole footprint smaller by about 20%. It’s just oversized for what it is, and there’s no benefit to the current size. If budget were no issue, or if this were to be manufactured in any reasonable quantity, I’d do injection molded tracks. This design would benefit greatly from a harder material on the cog surface of the tank link, and a softer traction material for the ground contact portion of the trank link. Unfortunately the RFQ I sent out for a low volume mold came in about where I expected it, around six thousand dollars. This project has been fun, but not $6k fun.