3d Calcs
CONFIG:
130 W
$0.15/kWh
$20.00/kg spool
Reference & Specs MODULE

Hole, Shaft & Tolerance Compensation Calculator

Compensate for printed hole shrinkage and plastic contraction in CAD or slicer X-Y hole compensation for press-fit, sliding, or clearance pins.

Feature Geometry
mm
mm

Firm hand push; stays in place without falling out.

CAD Compensation RecommendationShrinkage & Fit
Model This Diameter in CAD
10.35mm
Nominal (10.0) + Shrinkage (+0.25) + Clearance (+0.10)
Slicer X-Y Hole Compensation+0.125 mm

Alternatively, keep CAD at nominal 10.0mm and apply this offset in OrcaSlicer/Bambu Studio (Quality → Precision → X-Y Hole Compensation).

FDM rule: Inner holes always shrink toward center due to plastic contraction and nozzle drag.
01 / PROTOCOL

Measurement & Operating Instructions

STEP 01

1. Select Feature Type

Choose whether you are modeling an internal hole or external pin/shaft.

STEP 02

2. Enter Measurements

Input nominal CAD dimension and your test print caliper measurement.

STEP 03

3. Select Fit Class

Choose Press Fit, Snug Fit, Sliding Fit, or Loose Clearance.

02 / MATHEMATICS

Hole Shrinkage & CAD Tolerance Compensation

Compensates for polymer thermal shrinkage, facet triangulation, and nozzle curve dragging on circular bores.

CAD Hole Diameter = Target Diameter + (Nominal − Measured) + Fit Clearance
Real-World Worked Benchmark:

You design a 10.0mm hole that prints at 9.75mm (0.25mm shrinkage). For a snug pin fit (+0.10mm clearance), model a 10.0 + 0.25 + 0.10 = 10.35mm hole in CAD.

Frequently Asked Questions

Why do 3D printed holes always come out smaller than designed?
Printed holes shrink due to two main physical factors: 1) Molten plastic contracts as it cools from 200°C+ down to room temperature. 2) As the nozzle turns a circular curve, surface tension pulls the molten bead inward toward the center of the arc.
What is X-Y Hole Compensation in Cura, Bambu Studio, and OrcaSlicer?
It is a slicer setting that offsets all internal hole perimeters outward while leaving external perimeter dimensions unchanged. A typical starting offset is +0.10mm to +0.15mm.
What clearance tolerance is needed for a smooth sliding 3D printed fit?
For a free-sliding fit (like a hinge or axle pin), leave a total diametrical clearance of 0.30mm to 0.40mm. For a light press-fit, use 0.10mm to 0.15mm clearance.
How do horizontal expansion and hole compensation differ?
Horizontal expansion scales the entire perimeter (both inside holes and outer walls). Hole compensation specifically targets internal enclosed closed loops without affecting outer dimensions.
Why are horizontal holes printed along the Z-axis prone to drooping?
Horizontal holes printed on their side require bridging across the top arch. Gravity pulls the unsupported top strands downward, creating an egg-shaped hole. Using a teardrop CAD profile solves this.
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