How to Use FreeCAD for 3D Printing: Step-by-Step Guide

To use FreeCAD for 3D printing, start by creating or importing a 3D model in the Part or Part Design workbench. Then export your model as an .stl file, which is the standard format for 3D printers. Finally, use slicing software to prepare the file for printing.

Syntax

In FreeCAD, the basic workflow for 3D printing involves these steps:

• Create or import model: Use the Part or Part Design workbench to build or load your 3D object.
• Check and repair model: Ensure the model is a solid and has no holes or errors.
• Export model: Save the model as an .stl file for 3D printing.

The key command to export is:

File > Export > Select "STL Mesh (*.stl)"

python

import FreeCAD
import Part

# Create a simple box
box = Part.makeBox(10, 10, 10)
Part.show(box)

# Export the shape as STL
__objs__ = []
__objs__.append(FreeCAD.ActiveDocument.Objects[0])
import Mesh
Mesh.export(__objs__, "box.stl")

Output

Creates a 10x10x10 mm cube and exports it as 'box.stl' file.

Example

This example shows how to create a simple cube in FreeCAD and export it as an STL file ready for 3D printing.

python

import FreeCAD
import Part

# Create a cube of 20x20x20 mm
cube = Part.makeBox(20, 20, 20)
Part.show(cube)

# Export the cube as STL
__objs__ = []
__objs__.append(FreeCAD.ActiveDocument.Objects[0])
import Mesh
Mesh.export(__objs__, "cube.stl")

Output

A 20x20x20 mm cube is created and saved as 'cube.stl' for 3D printing.

Common Pitfalls

Common mistakes when using FreeCAD for 3D printing include:

• Exporting models that are not solid or have holes, causing print errors.
• Forgetting to check model scale, resulting in prints that are too big or small.
• Not using the correct export format; 3D printers usually require .stl files.
• Ignoring model orientation, which can affect print quality and support needs.

Always use the Part workbench tools to check and fix your model before exporting.

python

## Wrong way: Exporting a non-solid shape
# This will cause errors in slicing software

# Right way: Make sure the shape is a solid
solid_shape = cube.makeSolid()
Part.show(solid_shape)

# Then export as STL

Quick Reference

Tips for using FreeCAD for 3D printing:

• Always design in millimeters for 3D printing.
• Use the Part Design workbench for parametric solid models.
• Check model integrity with the Check Geometry tool.
• Export models as .stl files via File > Export.
• Use slicing software like Cura or PrusaSlicer after exporting.

Key Takeaways

Create or import a solid 3D model in FreeCAD's Part or Part Design workbench.

Always export your model as an STL file for compatibility with 3D printers.

Check your model for holes or errors before exporting to avoid print failures.

Design using millimeters and verify scale to ensure correct print size.

Use slicing software after exporting to prepare the model for printing.