TPU 98A tops the ranking for a case brief — flexibility weighted heavily, with some strength and some ease of printing — followed by TPU 95A, then PLA, then TPU 85A.
The gap between the two TPUs at the top is the whole decision.
98A versus 95A
TPU 98A carries a difficulty rating of 2 — the same as PETG — because it is stiff enough to feed like a normal filament. It still flexes enough to snap over a handset and to soak up a drop. For a first flexible print, that combination is the right choice.
TPU 95A is the classic case material: grippier in the hand, more forgiving of a rough fit, and unmistakably rubbery. It is rated difficulty 3 and prints at around 30 mm/s, so the same case takes 3.36 hours instead of 1.02.
TPU 85A appears on the list and should be ignored here. At difficulty 5 it needs a fully constrained filament path and speeds under about 15 mm/s, and a case does not need to be that soft.
Why PLA is on the list and should not be used
The selector ranks it third because it scores on strength and ease. It fails the actual job twice over:
- Its heat deflection band is 52 to 60 °C, which is precisely what a parked car reaches in summer
- Its failure mode under impact is to crack, and a case exists to absorb impacts
A PLA case is a case that will either warp on a dashboard or shatter on the first drop, and the case's whole purpose is to prevent the second thing.
PETG, if you want it rigid
A reasonable middle: 68 to 80 °C of heat resistance, good UV rating, tougher than PLA, and about $0.74 of filament for a 31 g case at $24 a kilogram. It will not grip like TPU and it will transmit a drop to the phone, but it prints on anything.
The part that decides everything
Fit. Camera cutout, button positions, port clearance and corner radius all have to match one specific handset, and getting them right normally takes two or three iterations regardless of material.
Rank the options against your own weighting in the material selector, and cost them in phone case print cost.