3D Printing Shrinkage & Fit Tolerance Calculator

Your dimensions and tolerance configurations are processed locally in your browser.

Parámetros de Contracción Térmica

Print material

Estimated thermal shrinkage (%)

Target final dimension (mm)

The exact target size you want after cooling

Slicer Scale Factor (%)

100.81 %

Aplica 100.81% en los ejes X e Y de tu slicer.

Dimension to design in CAD (mm)

100.81 mm

Compensación Total

+0.81 mm

Para una pieza final deseada de 100 mm en ABS, el modelo se encogerá 0.81 mm al enfriar a temperatura ambiente.

Mastering Tolerances and Shrinkage in 3D Printing

Unlike CNC machining, 3D printing involves semi-liquid polymer deposition that contracts during phase change from molten to ambient temperature. Designing exact 22.0 mm pockets for 22.0 mm bearings always results in parts that do not fit. By applying correct radial clearances and compensating thermal shrinkage via slicer scaling factors, your parts will assemble seamlessly straight from the print bed.

Frequently Asked Questions about 3D Fit Tolerances

Why do 3D printed circular holes always shrink smaller than modeled in CAD?

Holes printed with FDM shrink due to three factors: polygon facet faceting (STL chordal error), surface tension pulling the extruded thermoplastic bead toward the curve center, and thermal contraction as plastic cools from ~220°C to room temperature. Inside holes typically end up 0.2 to 0.4 mm undersized.

How much do common filaments shrink during 3D printing?

PLA has minimal shrinkage (~0.2% to 0.3%). PETG shrinks around 0.3% to 0.5%. ABS and ASA experience significant thermal shrinkage (~0.7% to 0.9%). Nylon (polyamide) shrinks the most, typically between 1.2% and 1.8%.

What hole diameter should I model in CAD for a standard 608 bearing (22 mm OD)?

For a firm press fit with a light mallet tap, model the hole at Ø 22.08 mm. For a snug push fit by hand, design it at Ø 22.18 to 22.20 mm. For a loose sliding pocket, model at Ø 22.35 mm.

What hole size is needed for M3 screws and brass threaded inserts in 3D prints?

For free clearance pass holes where the M3 bolt slides through, design Ø 3.3 to 3.4 mm. For direct self-tapping into plastic, use Ø 2.6 to 2.8 mm. For standard M3 heat-set brass threaded inserts (M3x4x5), model a tapered pilot hole between Ø 4.0 and 4.2 mm.

3D Printing Shrinkage & Fit Tolerance Calculator

Mastering Tolerances and Shrinkage in 3D Printing

Frequently Asked Questions about 3D Fit Tolerances

Why do 3D printed circular holes always shrink smaller than modeled in CAD?

How much do common filaments shrink during 3D printing?

What hole diameter should I model in CAD for a standard 608 bearing (22 mm OD)?

What hole size is needed for M3 screws and brass threaded inserts in 3D prints?

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