How Does FreeCAD Perform
with Sheet Metal Parts?
A complete, honest look at the FreeCAD Sheet Metal Workbench — from installation and bending flanges to the all-important Unfold feature and DXF export for laser cutting and CNC. Is this a genuine free alternative to SolidWorks and Fusion 360? We break it all down.
FreeCAD Sheet Metal Workbench in action — bent 3D model alongside its unfolded flat pattern
When it comes to designing sheet metal parts in free CAD software, FreeCAD is always the first name that comes up. But can it actually replace commercial tools like SolidWorks, CATIA, or Fusion 360 for real production work? In this article we give a thorough, hands-on answer based on practical experience with the FreeCAD Sheet Metal Workbench.
FreeCAD Sheet Metal is a free, community-developed add-on that must be installed separately. It brings dedicated tools for sheet metal design — bending, unfolding flat patterns, punching holes, flanges, forming features, and more.
What Is the FreeCAD Sheet Metal Workbench?
FreeCAD does not ship with a dedicated sheet metal environment by default — but thanks to an active developer community, the Sheet Metal Workbench was created as a powerful external add-on. It brings all the specialized tools you need when working with thin, bendable plate material.
The core workflow mirrors professional tools: define material thickness, sketch a base, add bent flanges, punch holes, and finally unfold the whole part into a flat 2D pattern ready for laser cutting or CNC punching. Simple in concept — but with a few practical quirks worth knowing about before you start.
A complex bent sheet metal bracket modeled entirely in FreeCAD Sheet Metal Workbench
The workbench is maintained on GitHub and is updated regularly. As of FreeCAD 1.0, stability has improved dramatically — making it a genuinely viable option for everyday professional use at hobby and small-business scale.
Installation & Setup
Installing the Sheet Metal Workbench takes under five minutes using FreeCAD's built-in Addon Manager. Here's exactly how to do it:
Go to Tools → Addon Manager. This is built into every FreeCAD version from 0.20 onward — no external download required.
Type SheetMetal in the search field. The SheetMetal workbench by shaise will appear. Click Install.
A restart is required after installation. The workbench then appears in the workbench dropdown list.
Select Sheet Metal from the workbench dropdown. A new dedicated toolbar appears with all Sheet Metal tools.
Before starting any model, set the correct K-factor for your material (steel, aluminium, copper). This directly controls the accuracy of your flat pattern development.
Always use the latest stable release of FreeCAD together with the latest Sheet Metal addon. FreeCAD 1.0+ introduced a more stable topology engine which drastically reduces the infamous "broken model" errors when editing dimensions.
Key Tools & Features
The Sheet Metal Workbench packs a comprehensive set of purpose-built tools. Here is an overview of the most important ones:
Creates the sheet metal base from a flat Sketch. Defines material thickness and growth direction.
Adds a bent flange to any edge. Fully parametric — set bend angle, height, radius, and offset.
Unfolds a 3D bent part into an accurate 2D flat pattern using configurable K-factor bend compensation.
Bend along a custom user-defined sketch line — ideal for non-standard angles and complex forms.
Full integration with PartDesign for punching holes, slots, and pockets into the sheet metal body.
Create 3D emboss relief features in the sheet — louvers, beads, dimples, and custom stamp forms.
Automatically adds corner relief cuts at bend junctions — essential for real-world manufacturability.
Export the unfolded flat pattern directly as DXF or SVG for laser cutting, CNC punching, or plasma cutting.
Step-by-Step: Building a Sheet Metal Part
Step-by-step workflow: from flat Sketch to finished 3D sheet metal enclosure
Let's walk through a concrete example — building a simple L-bracket enclosure from 2mm mild steel sheet.
Step 1 — Create the Base Wall
Open the Sheet Metal Workbench and create a new Sketch on the XY plane. Draw a rectangle of 100 × 80 mm. Use Make Base Wall and set thickness to 2 mm. You instantly get a thin sheet solid in 3D space.
Step 2 — Add Bent Flanges
Select an edge of the base wall and click Make Wall. Set the bend angle to 90°, flange height to 40 mm, and bend radius to 1 mm — a standard value for 2 mm mild steel. Repeat for all edges that require bending. Each flange is parametric and can be adjusted at any time.
Step 3 — Add Holes and Cutouts
Switch to PartDesign mode, create a Sketch on any face of the sheet metal part, and use the standard Pocket feature or dedicated hole tools. The Sheet Metal Workbench is fully compatible with PartDesign operations throughout the entire model tree.
Always pay close attention to the order of operations in the model tree. Holes and pockets added before all bends are defined can cause Unfold errors. Best practice: finalize all bends first, then add holes and cutouts.
Step 4 — Unfold and Verify the Flat Pattern
Once the 3D model is complete, use the Unfold tool. FreeCAD automatically computes the flat development accounting for the K-factor. The result is a precise 2D flat pattern ready for production.
Unfolding & DXF Export for Laser Cutting
The Unfold result — a precise flat pattern development ready for laser cutting or CNC punching
The Unfold feature is the most critical function in the entire Sheet Metal Workbench — and this is where FreeCAD both shines and has some limitations worth noting.
How Unfolding Works
FreeCAD uses the K-factor method to calculate bend compensation. The K-factor defines the position of the neutral axis during bending — directly determining the correct developed length of the flat blank. Recommended starting values:
| Material | K-Factor (recommended) | Notes |
|---|---|---|
| Mild Steel | 0.44 | Most commonly used default |
| Aluminium | 0.40 | Softer, slightly lower K |
| Stainless Steel | 0.46 | Harder material, higher K |
| Copper | 0.38 | Very ductile |
| Brass | 0.40 | Similar to aluminium |
Exporting DXF for Laser Cutting
After running Unfold, the export workflow is straightforward:
1. Select the Unfold object in the model tree.
2. Go to File → Export.
3. Choose DXF format (Autodesk DXF R14 recommended for maximum compatibility).
4. Verify the contour in LibreCAD, Inkscape, or your laser software.
5. Send to the laser cutter — done.
Use the TechDraw Workbench to generate a dimensioned technical drawing of your unfolded flat pattern. This is especially useful when communicating with CNC operators who do not work directly with CAD files.
Pros & Cons
- Completely free and open-source
- Accurate Unfold with adjustable K-factor
- Solid integration with PartDesign
- DXF and SVG export for production
- Actively developed and improving
- Works on Windows, macOS and Linux
- Fully parametric — change dimensions anytime
- Great community support and documentation
- Steeper learning curve than SolidWorks
- Complex geometries can destabilize the model
- No automatic Bill of Materials (BOM)
- Forming tools are basic compared to competitors
- Topological naming problem can break models on edit
- No real-time bending simulation
- Limited sheet metal-specific drawing automation
Comparison with Commercial CAD Tools
| Feature | FreeCAD | SolidWorks | Fusion 360 | CATIA |
|---|---|---|---|---|
| Price | Free | $4,000+/yr | $680/yr | $25,000+ |
| Unfold accuracy | ⚡ Good | ✓ Excellent | ✓ Excellent | ✓ Excellent |
| DXF export | ✓ | ✓ | ✓ | ✓ |
| Forming tools | ⚡ Basic | ✓ Advanced | ✓ Advanced | ✓ Advanced |
| Bend tables | ⚡ Manual | ✓ Full | ✓ Full | ✓ Full |
| Model stability | ⚡ Medium | ✓ High | ✓ High | ✓ High |
| Linux support | ✓ | ✗ | ✗ | ✗ |
| Open Source | ✓ | ✗ | ✗ | ✗ |
For hobbyists, students, and small fabrication shops, FreeCAD Sheet Metal is an absolutely viable choice. For high-volume production with hundreds of complex stampings, commercial tools still have a clear edge — but that gap narrows with every FreeCAD release.
The FreeCAD Sheet Metal Workbench is surprisingly capable for a free tool. Accurate Unfold, reliable DXF export, and deep integration with the rest of FreeCAD make it excellent for hobbyists, students, and small workshops. Its main weaknesses are occasional instability with complex geometries, basic forming tools, and the infamous topological naming problem. But at zero cost, it is hard to argue against it.
Frequently Asked Questions
Conclusion
The FreeCAD Sheet Metal Workbench has come a long way from its early days as an unstable hobby add-on. Today it stands as a genuinely capable CAD option for sheet metal design — one that does not cost a single cent.
If you are a maker, engineering student, small shop owner, or engineer working on personal projects, this workbench gives you everything you need. SolidWorks and Fusion 360 still lead on complexity, polish, and advanced forming capabilities — but for a solid 90% of everyday sheet metal tasks, FreeCAD delivers.
Start with simple parts, learn to calibrate the K-factor against your actual material, and you will quickly discover that this free tool is far more capable than most people expect.
Find more FreeCAD Sheet Metal tutorials, technical drawings, and downloadable 3D models right here on FreeCAD Extreme. Follow the blog for new content every week!
