Computer-Controlled Machining

For this week’s Computer-Controlled Machining assignment, the goal was to "make something big" using CNC machining. I wanted to create something both functional and aesthetically pleasing—so I designed and fabricated a custom desk.

This project wasn’t just about cutting wood; it involved designing for CNC constraints, optimizing toolpaths, understanding material properties, and ensuring a structurally sound build. Here’s my step-by-step journey through the process:

Sketching the Design

I started with a top-view sketch of the desk in Fusion 360, defining the primary dimensions and the layout. This step was crucial in establishing the overall proportions and ensuring that all elements fit together harmoniously.

Extruding the Form

Once the sketch was finalized, I extruded the design to give it volume, transforming the 2D sketch into a 3D object. This gave me a clearer visualization of how the final piece would look.

Designing and Extruding Leg Supports

The desk required sturdy leg supports, so I designed five legs that would provide stability. Each leg was modeled and then extruded to match the desired thickness.

Creating Attachments for Structural strenth

Since the desk had five legs, I needed a way to secure them together to avoid wobbling. I designed attachments that would interlock and firmly hold the legs in place.

Adding Drawers for Functionality

A desk isn’t complete without storage! I integrated drawers into the design to add practicality, ensuring they fit seamlessly into the structure.

Preparing for CNC Machining

With the design finalized, I moved to the Manufacturing workspace in Fusion 360 to prepare for CNC machining. This included:

Setting Up the CNC Job

Transitioning to the Manufacture workspace in Fusion 360, I defined: - Stock dimensions (matching my plywood sheet) - Workpiece origin & zero point - Tool selection for optimal cutting efficiency

Toolpath Generation – 2D Contour

I selected the 2D contour strategy to create precise outer cuts for each component. Key settings: - Multiple depth passes to prevent excessive tool load

Holding tabs to secure the pieces during cutting

Optimized toolpath order for efficient machining

Simulation & Verification

Before executing the cut, I ran a toolpath simulation to verify:

Proper clearances and cut depths
Prevention of collisions or tool crashes

Exporting G-Code & Running the CNC Machine

Once the toolpaths were validated, I:

Exported the NC file for the CNC router
Loaded the plywood sheet onto the machine
Executed the cutting process step by step

Post-Processing & Finishing

After cutting, I focused on refining the desk’s surface for a polished final look.

1) Sanding the Cut Pieces - I used coarse-grit sandpaper (80–120 grit) to remove burrs and sharp edges. - Then, I followed up with fine-grit sandpaper (220+ grit) for a smooth finish.

2) Filling Gaps & Imperfections - I applied wood filler to minor gaps and surface imperfections. - After drying, I sanded again to ensure a uniform surface.

3) Coating & Sealing To enhance durability, I applied: - A wood primer to seal the surface. - A matte polyurethane coating for protection and aesthetics. 4) Polishing & Final Touches - Once the coating dried, I lightly polished the surface to achieve a refined, smooth texture with a natural wood finish. - The final result was a sleek, professional-looking desk ready for assembly and use.