## 3D Printing Guide (TPU)

TPU is flexible and slightly tricky compared to PLA. The settings below are
a safe starting point for a 0.4 mm nozzle and any TPU rated **shore 90A–95A**.
Softer TPU (e.g. 85A) is harder to print and usually requires a direct-drive
extruder.

### Slicer settings

| Setting             | Recommended value                                  |
|---------------------|----------------------------------------------------|
| Layer height        | 0.16–0.20 mm                                       |
| Wall / perimeters   | 3 walls                                            |
| Top / bottom layers | 4–5 (the pad is short, so this fills it solidly)   |
| Infill              | 30–60% gyroid (gyroid keeps the part flexible)     |
| Print speed         | 20–30 mm/s for walls, 25–35 mm/s overall           |
| Travel speed        | 80–120 mm/s                                        |
| Retraction          | Direct drive: 0.5–1.5 mm @ 25 mm/s. Bowden: avoid retraction or keep it short and slow. |
| Nozzle temperature  | 220–235 °C (follow the filament label)             |
| Bed temperature     | 40–60 °C                                           |
| Cooling fan         | 30–60% after the first layer                       |
| Z-hop               | Disabled                                           |
| Adhesion            | Brim 3–5 mm — the part is small and TPU adheres differently than PLA |
| Supports            | Not needed for the default model                   |

### Before pressing print

1. **Dry the filament.** TPU is hygroscopic; wet TPU bubbles, stringy, and
   prints poorly. 4–6 h at 50 °C in a filament dryer is usually enough.
2. **Clean the bed.** Isopropyl alcohol is fine; do **not** use glue stick or
   PVA on a smooth PEI sheet — TPU can bond too strongly and chip the plate.
   Hairspray works as a release layer if adhesion is too aggressive.
3. **Check the extruder tension.** Too tight and TPU will deform between the
   gears and grind; too loose and it slips. Aim for the lightest setting that
   still feeds reliably.
4. **Slow the first layer** to ~15 mm/s for clean adhesion.

### After printing

- TPU rarely warps, so let it cool on the bed for a minute and it will pop
  off easily.
- The grip dots may have small strings; trim them with a sharp knife.
- If you need a softer feel, lower the infill; for more load capacity raise
  it or add walls.

### Sizing tips for the actual application

- Measure the desk leg footprint and add ~4 mm on each side so the leg sits
  comfortably inside the pad.
- Pick a height that fully closes the gap you are trying to shim. For a
  wobbly desk where one leg is 3 mm short, a 5–6 mm pad under that one leg
  is ideal.
- For chair wheels or rolling furniture, this pad is **not** the right tool;
  use a non-rolling pad without grip dots instead.