Computer Controlled Cutting

A Chair Fit for a King

The biggest challenge this week was translating ideas into practical CAD designs. While I'm getting more comfortable with CAD tools, I still struggle with the logistics of execution—I can visualize what I want to make, but understanding the structural math behind whether it will actually work is difficult.

After spending too many hours without progress, I found a valuable resource: 3axis.co offers free woodworking project files.

I wasn't confident about how to properly scale joints when modifying an imported file. The folding chair seemed like it would work at different scales. I measured the width between pieces to ensure they fit the bit and board, but didn't carefully consider the overall scale. My "chair" ended up over 6 feet tall!

Critical Manufacturing Settings & Checks:

XYZ Axis Position:

Tab Height: Increased to 0.1 inches
Tab Distance: Set to 5 inches apart
Bottom Height: I initially missed adding this value. Must be set to cut through material thickness
Multiple Passes: Set to 0.3 inches per pass to avoid cutting through the board in one go
Toolpath Verification: Check that the blue line is cutting on the correct side of your pieces before exporting
Other Settings: All default Fusion 360 settings were used with no other modifications

After completing the project, I noticed several structural issues:

Structural Issues Identified:

Weak back notches: The notches where the seat hooks into the back legs seem really fragile
Missing features: Comparing to the original image, the Y-shaped back piece should have notches for the seat, but the DXF file didn't include these. Currently, the seat just balances in a delicate way that doesn't feel secure
Connection system: Would benefit from hinges connecting all pieces to make folding/unfolding easier and more reliable

Useful Links
CBA ShopBot User Guide
Nifty Dogbone Extention for Fusion

Files
Chair.dxf
Chair.sbp