HTPLA Guide: Heat-Treatable PLA
How annealing works
Standard PLA is mostly amorphous, which is why it softens at 55 C. HTPLA contains nucleating agents that let the polymer crystallise when heated. Crystallisation raises the heat deflection temperature dramatically and improves stiffness. The part also shrinks (typically 1 to 3 percent) as the polymer chains pack tighter.
The annealing process
- Print at standard PLA settings (200 to 220 C)
- Wait until the print is at room temp
- Place the part on a flat tray (sand or salt fills voids and supports the part)
- Bake at 110 C for 15 to 30 minutes depending on part size
- Cool slowly inside the oven; rapid cooling can warp the part
- Verify the new dimensions after cooling
Shrink margin
Design the part 1 to 3 percent oversize before annealing. Test on a sacrificial print first, especially for parts with tight tolerances. Walls and infill density both affect shrink rate.
When HTPLA wins
- Parts that need PLA's easy print and finish, plus PC-like heat resistance
- Tools and jigs that face occasional heat
- Functional under-bonnet components (after annealing)
- Anything that lives near a heat source