Flexi Rex with Stronger Links
An articulated T-Rex that flexes and moves without glue or assembly. The joints are printed in place — a showcase of what FDM can do that injection moulding can't.
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- Author
- DrLex (remix: Kirbs → airfish/zheng3)
- License
- CC-BY-SA-4.0
- Print time
- ~2h 20m
- Layer height
- 0.2 mm
- Supports
- None
- Filament
- PLA
3D preview
Why print this
Print-in-place hinges are one of FDM’s genuine superpowers. The joints are designed with a tiny clearance gap — they print fused together but separate when you flex them. This model makes that concept tangible in the most satisfying way.
License note: Flexi Rex with stronger links by DrLex is licensed under CC BY-SA 4.0. Based on Flexi Rex by Kirbs, airfish, and zheng3.
Before you slice
3 perimeters, 15% infill. Do not touch or flex the model until it has fully cooled — the joints are fragile while the PLA is still warm. Use standard PLA (PETG and ABS have different clearance requirements and may not work with these tolerances).
No supports required. The joints have built-in clearance.
What to expect
- Slice with 3 perimeters, 15% infill, no supports.
- Print time is approximately 2 hours 20 minutes.
- Do not remove from the bed until it is fully cool to room temperature. Wait 30 minutes after the print ends.
- Remove from the bed gently.
- Flex the tail and neck joints slowly, side to side. They will be stiff at first.
- Work each joint through its range of motion with gentle pressure. You’ll feel them free up.
If it goes wrong
- Joints won’t flex at all (fused solid) — first layer was over-squished, closing the clearance gap. Raise Z offset slightly by 0.05 mm and reprint.
- Joints too loose / model flops — first layer too far from the bed, or flow rate too low. Check Z offset.
- Joints cracking when flexed — flexed while still warm, or PLA is brittle (old filament, wet filament). Wait until fully cool; dry filament if needed.
- Missing segments — check layer preview for any gaps in the design. Ensure the correct STL was downloaded (the “stronger links” version).
Recommended slicer settings
Paste into PrusaSlicer or OrcaSlicer — adjust to taste.
layer_height: 0.2 mm infill: 15% perimeters: 3 supports: none filament: PLA nozzle_temp: 200°C bed_temp: 60°C speed_print: 50 mm/s