Design a 3D-printed robot arm by talking to Claude Code
Idea + starter prompt, not run by us yet
For: Hobbyists who want to build hardware but have never used CAD
Claude Code wrote one macro that FreeCAD re-rendered live, so the whole arm came from conversation. The builder printed and assembled it, then added voice and webcam control: speech and an image go to Claude, which returns JSON actions that local code turns into servo angles on an ESP32. About 30 hours produced four working servos.
Steps
- Install FreeCAD and ask Claude Code to write one macro that builds your design. Tell it the parts, sizes and servos you have.
- Iterate by chat and look at each render before you print.
- Plan for reprints. The builder taped servos, glued a lid, redid a base and replaced a failed hinge.
- Remember FreeCAD's macro runner needs ASCII-only scripts, so ask Claude to avoid special characters.
- Test with power limited and your hands clear of the arm. There is no feedback loop and calibration is rough.
Starter prompt
Trial first: build only one test part, a simple bracket sized for [servo model], in a new folder called [arm-trial]. Do not design the whole arm until I have printed and checked that part. I want to design a small 5-joint robot arm in FreeCAD using only a Python macro. My servos are [model, size], my printer bed is [size] and my material is [PLA or other]. List the parts you plan to build with their dimensions, and ask me anything unclear. Then write one macro file I can re-run after every change, with ASCII characters only. Build one part at a time and stop for my feedback. Warn me about parts that are hard to print, like print-in-place hinges. Stop and wait for my yes before writing any motor control code or anything that moves hardware. A finished design is not permission to power it up.
Original post: hiitzroman.com · found via agentusecases.ai. Written up in our own words. We haven't run it, so test it on made-up data first.