Dimensional inaccuracy means the printed part does not match the intended dimensions from the 3D model. Parts may be too large, too small, or inconsistent across different axes, making them unfit for assemblies or functional use.
Common Causes
- Uncalibrated steps/mm — The motion system moves more or less than commanded
- Over-extrusion or under-extrusion — Excess or insufficient material changes wall thickness
- Thermal shrinkage — Materials contract as they cool, especially ABS and Nylon
- Belt tension inconsistency — Loose belts on X or Y axes cause dimensional errors
- Elephant foot on first layer — Excess squish on the first layer widens the base
- Slicer compensation not set — No horizontal expansion offset configured
Recommended Fixes
- Calibrate XYZ steps/mm using a calibration cube and calipers
- Print a calibration cube (20x20x20mm) and measure with digital calipers
- Adjust flow rate to eliminate over/under-extrusion affecting wall dimensions
- Apply horizontal expansion compensation in your slicer (-0.1 to -0.2mm typical)
- Tighten belts evenly on both X and Y axes
- Account for material shrinkage in your model design (ABS ~0.7-0.8%)
- Use elephant foot compensation in your slicer for accurate base dimensions