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FreeCAD Overview

FreeCAD is a free, open-source parametric CAD software that lets you create and modify 3D models with precision. For the Ender 3 CNC project, FreeCAD is used to design custom parts, adjust dimensions for your frame, and generate models for 3D printing.

Whether you’re resizing a carriage plate, designing a clamp, or checking fitment, FreeCAD provides the flexibility to make your CNC build repeatable and accurate.

Why FreeCAD?

  • Parametric Design: Modify any dimension or feature without starting over.
  • Community Driven: Active development and many tutorials.
  • Cross-Platform: Runs on Linux, Windows, and macOS.
  • File Export Options: Supports STEP, STL, DXF, and more — ideal for CNC and 3D printing workflows.

1. Adjust Existing Parts

Many Ender3CNC components are already designed in FreeCAD. You can open the .FCStd files and tweak dimensions:

  • Carriage spacing
  • Clamp thickness
  • Pulley clearance
  • Mounting hole positions

Tip: Always save a backup of the original before making changes.

2. Create Custom Parts

Need a new part for your CNC? FreeCAD lets you:

  1. Sketch 2D geometry on a plane.
  2. Extrude, pad, or cut features to create a 3D model.
  3. Add mounting holes, fillets, or chamfers for strength and fit.
  4. Export to .STL for 3D printing or .STEP for CNC machining.

3. Verify Fit and Assembly

Use FreeCAD’s Assembly Workbench or simply check parts visually:

  • Ensure rails and carriages align.
  • Confirm belt paths are unobstructed.
  • Check that the Z probe or endstops have proper clearance.
  • Units: Millimeters
  • Snap increments: 0.1 mm for fine adjustments
  • Export resolution: High for smooth 3D printing surfaces

FreeCAD Video Tutorial

If you add the mkdocs-video plugin, you can embed a demo video of adjusting parts:

FreeCAD CAM Tutorial

Resources