2020 T-slot extrusion
The Lego of robot frames. Bolt-together, reconfigurable, and available in every length. Not as stiff per gram as carbon, but you can rebuild the robot in an afternoon.
The role it plays
Structure is a stiffness-per-gram competition. Aluminium extrusion is cheap and modular but its bolted joints creep. Carbon is stiffer per gram and fails without warning. Printed parts win on geometry freedom and lose on layer adhesion. Match the material to the load path, never the other way round.
Typical use: Frames, gantries, mounts, enclosures.
What the numbers actually mean
The headline figure is 20 × 20 mm (profile), with 6 mm T-slot as the next most load-bearing number (slot). At $8 in the structure tier it sits cheap enough to prototype with and replace without regret, which is the correct way to learn a new subsystem.
How it compares
Same subsystem, closest alternatives. The primary spec column is usually the one that decides it.
| Part | Price | Primary spec | Second spec |
|---|---|---|---|
| 2020 T-slot extrusionStructural profile | $8 | 20 × 20 mm | 6 mm T-slot |
| 4040 T-slot extrusionStructural profile | $16 | 40 × 40 mm | 8 mm T-slot |
| 16 mm carbon fibre tubeComposite tube | $25 | 16 mm | 1 – 2 mm |
| PA-CF printed structural parts3D-printed composite | $40 | ~70 – 100 MPa (depends on print) | ~150 °C (annealed) |
Where it shows up
It is a component-level choice rather than a defining part of a named platform — pick it for the subsystem it serves, not to match a reference build.