Printing TARS, Part 2: Legs, Arms, and TPU Footpads
With the body printed, you finish the set: the legs, the arm and finger parts if you are doing the full-arms build, the flexible footpads, and the many small brackets and connectors that hold everything together. This lesson covers the two skills that turn a pile of fresh prints into parts that are actually ready to assemble: printing a flexible material, and post-processing.
Printing flexible TPU
Most of TARS is rigid PETG, but the footpads are printed in TPU, the flexible filament, so they grip the floor and cushion the robot's steps. TPU prints differently from a rigid plastic, and it is worth slowing down for. Because it is soft, it feeds more slowly and does not like to be pushed fast, so these prints run slower and reward steady, unhurried settings. Do not be surprised that a small flexible part takes longer than a larger rigid one; that is normal. Using a flexible material exactly where you need flexibility, and a rigid one everywhere else, is the same match-the-material-to-the-job principle from the printing fundamentals, made concrete: nobody wants a rigid foot that skids, or a floppy chassis that sags.
Removing supports without wrecking the part
The support material you printed under overhangs is temporary scaffolding, and now you take it off. Tree supports snap away more easily than solid blocks, but this is where impatience does real damage. Work gently: pull and cut so the support comes away without gouging the surface underneath or snapping a thin feature, and use flush cutters and a hobby knife for the stubborn bits tucked into corners. The reason to be careful is not just cosmetic. Clean support removal leaves smooth surfaces and, crucially, open holes, and those holes are where servos seat, where screws thread, and where parts join. A hole half-clogged with leftover support is a servo that will not fit later, so clear every one.
Post-processing and checking the fit
A little finishing after the supports come off makes assembly far smoother. Pick off any stray strings, make sure every hole is clear, and check that mating surfaces are smooth. Then test the fit. Small differences between printers mean a hole your printer produced might come out slightly tight or slightly loose, and the moment to discover that is now, on the bench, not halfway through bolting the robot together. If a part designed to slot into another is too tight, a light pass with a file or a quick reprint fixes it; if you skip this and force parts together, you crack printed plastic. Test-fitting mating parts before final assembly is the difference between an assembly session that clicks together and one that fights you at every joint.
Which parts you print depends on whether you are doing the legs-only or full-arms build, and the TARS-AI Community documents the complete file list, the calibration and tolerance checks, and any post-processing notes. Follow their guide for the specifics, and lean on their Discord if a part does not fit the way you expect:
Docs and files: docs-tars-ai.vercel.app · GitHub: github.com/TARS-AI-Community/TARS-AI · Discord: discord.gg/AmE2Gv9EUt
By the end of this stage you should have a full set of clean, well-fitting parts, rigid where TARS needs strength and flexible where it needs grip, with every hole clear and every mating surface checked. That set of parts is the raw material for the rest of the month, and the care you put into printing and finishing it now is what makes the assembly ahead a pleasure instead of a battle.