Fusion 360 Sheet Metal Design – Sheet Metal Workspace, Bending, and Flat Patterns

Introduction

Sheet metal is one of the most widely used materials in mechanical, industrial, and consumer product design. From automotive panels and HVAC ducting to enclosures for electronics and custom brackets, sheet metal design is a cornerstone of modern engineering.

Autodesk Fusion 360 Sheet metal design provides a dedicated Workspace that enables designers to create, edit, and unfold sheet metal parts with precise control over thickness, bend radii, and manufacturing rules. Unlike generic solid modeling, sheet metal design requires special considerations such as bending allowances, K-factors, and flat patterns.

What Is Sheet Metal Design?

Sheet metal design is a specialized CAD process focused on modeling thin-walled parts that will be cut and bent into shape during manufacturing. Unlike solid parts, sheet metal must be designed with flat pattern unfolding in mind.

Key considerations:

• Thickness consistency – The sheet maintains a uniform thickness.
• Bend allowances – Material stretches and compresses during bending.
• K-factor – Defines how material deforms within the bend.
• Flat pattern conversion – 3D bent designs must be unfolded for CNC laser cutting or punching.

Fusion 360 automates much of this process with built-in rules and unfolding tools.

The Fusion 360 Sheet Metal Workspace

Fusion 360’s Sheet Metal workspace is dedicated to creating thin-walled, manufacturable parts.

Accessing the Workspace

1. Open Design Workspace.
2. Switch from Solid to Sheet Metal tab.
3. Choose tools like Flange, Bend, Contour Flange, and Flat Pattern.

Sheet Metal Rules

The foundation of sheet metal design in Fusion 360 is Sheet Metal Rules, which control:

• Material thickness.
• Bend radius.
• Relief settings (rectangular, tear, round).
• K-factor or bend tables.

You can either:

• Use default rules (e.g., steel, aluminum).
• Or create custom rules to match manufacturing standards.

👉 Rules ensure that your part matches real-world shop capabilities.

Creating Sheet Metal Parts

Fusion 360 offers multiple tools to create sheet metal geometry:

1. Flange Tool

• Extends sheet metal from a sketch profile.
• Can be created from edges, faces, or profiles.
• Defines initial base flange for the part.

2. Bend Tool

• Adds bends between flanges.
• Automatically applies correct bend allowance.
• Adjustable bend radius and angle.

3. Contour Flange

• Creates sheet metal walls from a sketched profile.
• Perfect for ducts, brackets, and enclosures.

4. Hem Tool

• Folds edges to remove sharpness and strengthen parts.
• Common for consumer product casings.

5. Corner Relief

• Automatically applies relief cuts at intersecting bends.
• Prevents tearing during manufacturing.

6. Unfold & Refold

• Temporarily unfolds part for modifications (like cutouts).
• Refolds back into its bent state.

7. Flat Pattern

• Converts 3D sheet metal design into a flattened 2D layout.
• Essential for laser cutting, waterjet, or CNC punching.

Advanced Sheet Metal Workflows

Once you master the basics, Fusion 360 enables advanced sheet metal workflows.

Workflow 1: Creating an Electronics Enclosure

1. Sketch base rectangle → Apply Flange.
2. Add Bends for side walls.
3. Add Cutouts for ports (USB, power).
4. Apply Hems for safety edges.
5. Generate Flat Pattern for fabrication.

Workflow 2: HVAC Duct Design

1. Create Contour Flange from sketch profile.
2. Add bends and taper using Flange modifications.
3. Apply corner reliefs to prevent cracks.
4. Export DXF flat pattern to CNC plasma cutter.

Workflow 3: Sheet Metal Bracket

1. Start with Flange base.
2. Add multiple bend flanges for mounting holes.
3. Apply gussets for strength.
4. Export flat pattern with dimensions.

Editing and Refining Sheet Metal Parts

Fusion 360 makes editing easy by maintaining parametric history.

Key Editing Tools:

• Edit Flange – Adjust length, bend angle, or thickness.
• Edit Rule – Switch between sheet metal materials instantly.
• Unfold & Cut – Add holes or slots on flat surface before refolding.
• Convert to Sheet Metal – Transform solid body into sheet metal part.

👉 Tip: Use Convert to Sheet Metal for imported STEP or IGES files.

Flat Patterns – Preparing for Manufacturing

The Flat Pattern tool is the most critical feature in sheet metal workflows.

Creating a Flat Pattern

1. Finish part in bent state.
2. Select Flat Pattern tool.
3. Define fixed face (reference surface).
4. Fusion 360 unfolds part automatically.

Exporting Flat Patterns

• Save as DXF for CNC cutting.
• Export to CAM workspace for manufacturing.
• Share with fabricators for production.

Flat Pattern Features:

• Automatic bend lines with angle annotations.
• Bend tables included for reference.
• Preserves relief cuts and hems.

Analysis and Validation

Fusion 360 includes tools for validating sheet metal parts:

• Thickness Analysis – Confirms uniform sheet thickness.
• Interference Detection – Ensures bends don’t overlap.
• Flat Pattern Verification – Checks manufacturability.

Real-World Applications of Sheet Metal in Fusion 360

Automotive

• Chassis panels, brackets, HVAC ducts.

Aerospace

• Structural brackets, ducting, lightweight enclosures.

Consumer Products

• Laptop shells, speaker housings, appliances.

Industrial Equipment

• Control panels, machine guards, electrical enclosures.

Architecture & Construction

• Ductwork, roofing panels, HVAC systems.

Best Practices for Sheet Metal Design

1. Define Rules Early – Match shop material specs.
2. Keep Thickness Consistent – Don’t mix thicknesses in one part.
3. Use Reliefs – Prevent tearing during bends.
4. Plan for Manufacturing – Ensure bend radii match available tooling.
5. Avoid Over-Bending – Exceeding limits causes cracking.
6. Check Flat Pattern – Validate before sending to fabrication.
7. Minimize Complex Bends – Simplifies production and reduces costs.

Common Mistakes to Avoid

• Forgetting to apply sheet metal rules → leads to unmanufacturable parts.
• Creating too many tight bends → increases cracking risk.
• Ignoring bend reliefs → causes tearing during fabrication.
• Designing with mixed thicknesses → complicates cutting and bending.
• Skipping flat pattern validation → results in errors on CNC machines.

Fusion 360 vs. Other Sheet Metal CAD Tools

Fusion 360 stands out for its integration of sheet metal + CAM, allowing direct fabrication.

Future of Sheet Metal Design in Fusion 360

Autodesk is enhancing sheet metal tools with:

• AI-driven flat pattern optimization for material savings.
• Automated nesting for CNC cutting.
• Improved K-factor calibration for accuracy.
• Cloud collaboration for shop-to-designer feedback loops.

Case Study – Designing a Custom PC Case in Fusion 360

1. Define Rules → Steel, 1.5 mm thickness, bend radius 2 mm.
2. Create Base Flange → Bottom plate.
3. Add Flanges → Side walls and top cover.
4. Add Cutouts → Ventilation holes and USB ports.
5. Apply Corner Reliefs → Prevent tearing at intersections.
6. Generate Flat Pattern → Export DXF to laser cutting.
7. Simulate Assembly → Validate airflow and fitment.

Result: A manufacturable, lightweight, and professional PC case.

Conclusion

Fusion 360’s Sheet Metal Workspace provides a powerful, intuitive, and fully integrated solution for designing sheet metal parts. From flanges and bends to flat patterns and CAM export, it streamlines the entire workflow from design to manufacturing.

Key takeaways:

• Sheet Metal Rules ensure manufacturable designs.
• Flange, Bend, and Contour Flange are core creation tools.
• Flat Pattern is the bridge between CAD and fabrication.
• Fusion 360 simplifies real-world production with CAM integration.

Whether you’re designing simple brackets or complex enclosures, Fusion 360 gives you the tools to create precise, cost-effective sheet metal parts ready for fabrication.