Best filament for phone cases: flex or rigid

The short answerTPU for a flex case. PETG for a rigid shell.

A phone case either flexes to absorb drops or stays rigid to protect. TPU is the pick for a flexible, shock-absorbing case. PETG is the pick for a hard shell. PLA is too brittle for either job.

What a phone case asks of a filament

A phone case takes repeated drops, fits tight, and lives in a pocket. A flexible case bends to absorb shock and snaps back. A rigid case holds its shape and takes the impact on the shell. The filament must match the design.

How the materials compare

When to pick TPU

Pick TPU for a flexible case that absorbs drops. The Polymaker PolyFlex TPU95 sheet lists a nozzle of 210 to 230 °C. TPU needs a direct drive extruder and slow speeds, but it gives the case that stretches over the phone and bounces.

When to pick PETG

Pick PETG for a rigid shell that holds its shape. It is tough and resists impact, and it prints without a heated chamber. PLA is too brittle for a case, because it cracks on the first drop.

For each material, read the TPU guide or the PETG guide. For a rigid mount, see best filament for phone mounts.