Quality · 5 min read
Common FDM print failures and how design prevents them
Warping, layer splitting, stringing, sagging and other common FDM problems — what causes them and what helps.
Most print failures trace back to a handful of causes. Some are controlled at the printer; many can be prevented in the design.
Warping and lifting Plastic shrinks as it cools, so large flat parts can curl at the corners. Rounded corners, reduced flat areas and good bed adhesion help.
Layer splitting (delamination) Layers can separate under load or from uneven cooling. Orienting loads along layers and avoiding thin, tall walls reduces the risk.
Sagging and drooping Unsupported overhangs and long bridges droop. Chamfers, shorter spans and supports fix this.
Stringing Fine strands between features, more common with PETG. Usually a cosmetic issue that's tuned at the printer and cleaned during finishing.
Elephant's foot The first layers can squash outward slightly. A small chamfer on the bottom edge hides it.
Holes and fits too tight Printed holes often come out slightly undersized. Design clearance into holes and mating features, or plan to ream or drill.
Thin features breaking Pins, clips and thin walls can be too fragile. Thicken them or change orientation.
Mesh errors Open or non-manifold meshes can slice incorrectly. Our upload checks catch many of these before printing.
General guidance for FDM printing. Results depend on your geometry, material and use — ask us about your specific part.