Quality
Tolerance
Also known as: tolerancia · tolerance · holgura · clearance · ajuste · encaje
Short definition
Tolerance is the clearance you must leave between two parts so they fit, because 3D printing never reproduces the nominal dimension exactly.
Full definition
Material expands as it is laid down and contracts as it cools, the nozzle leaves a real line width that does not match the theoretical one, and holes come out systematically smaller than designed. That is why a part modelled to exact dimensions will not fit its mate. The values practice has settled on are around 0.2 mm clearance for a sliding fit and 0.1 mm for a press fit, but they change with the machine, the material and the temperature, so the only way to know yours is to print a tolerance test part. It is why two people print the same model and it fits for one and not the other.
Related terms
- Perimeters (walls)Perimeters are the outline passes the extruder traces at the edge of each layer; their number defines the real wall thickness of the part.
- NozzleThe nozzle is the final piece of the hotend, with a calibrated orifice through which molten material exits; its diameter sets the achievable detail and speed.
- STEPSTEP is a CAD interchange format that stores a part's exact geometry as mathematical surfaces rather than as an approximated triangle mesh.
Updated