Quality · 3 min read
Surface finish on FDM parts: what to expect
What an FDM surface looks like, how orientation and layer height affect it, and what finishing can and can't do.
FDM builds parts from extruded layers, so surfaces show fine lines. How visible they are depends on several things.
What controls the finish - Layer height: thinner layers look smoother but take longer - Orientation: vertical walls look best; gentle slopes show stair-stepping; top surfaces are smooth; supported surfaces are rougher - Material: PLA generally shows finer detail than PETG
Typical options - As printed: supports removed only where unavoidable - Supports removed and cleaned: support contact areas are cleaned up - Light sanding: smooths visible areas; won't remove all layer texture
Setting expectations FDM won't look like an injection-moulded or resin part straight off the printer. If a perfectly smooth cosmetic surface is essential, tell us which faces matter most — orientation alone often makes the biggest difference.
General guidance for FDM printing. Results depend on your geometry, material and use — ask us about your specific part.