Minimum wall thickness for FDM PETG enclosures that need to survive drops

Question

Our enclosure is 150 × 100 × 35 mm, printed in PETG with 0.4 mm nozzle. Currently 1.6 mm walls (4 perimeters). It cracks at the corners in a 1 m drop test.

Should I go to 2.4 mm walls, add internal ribs, or switch material? What wall/rib ratio works for you?

Lukas Novak · Answer

Also check your PETG is dry. Wet PETG loses a lot of layer adhesion and cracks along layer lines in drop tests — it looks like a design problem but it's a moisture problem.

Marcus Weber · Answer

1.6 mm PETG is thin for a 1 m drop. Before going thicker everywhere, try:

Corner radii ≥ 3 mm externally — sharp corners concentrate the impact.
Internal ribs 1.2 mm thick, 6 mm tall, at 25–30 mm pitch.
Print the wall with 5 perimeters only at the corners using modifier meshes.

That usually beats a blanket 2.4 mm wall on weight and print time.

Minimum wall thickness for FDM PETG enclosures that need to survive drops

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