Week 07 - Computer Controlled Machining

Group Assignment

Introduction & Assignment

individual

Project: The Modular Puzzle Table

Weekly Progress: From Digital Sketch to Physical Reality

The Challenge

This week’s mission was to bridge the gap between 2D Design and Large Format CNC Machining. I focused on creating a "tool-less" furniture system that relies on extreme precision rather than fasteners:

Modular: Units can be combined to form larger surfaces.

Glue-free: Designed to stay together using only friction and exact geometry.

Precision-driven: Utilizing micro-tolerances for a perfect fit.

Step 1: Designing for the "Perfect Click"

1) I engineered the project in Onshape with a focus on assembly physics and material behavior.The Tolerance: To ensure the table stays together without glue, I expanded the joints by 0.35 mm.

2) The Math: For the 10 mm plywood, I designed 10.35 mm slots. This tiny gap (0.35 mm) provides enough room for assembly while maintaining a rock-solid friction fit.

3) Modular Logic: The "puzzle" tabs allow for easy expansion. Two tables create a 1-meter surface (1000 mm), and three create a 1-meter workspace.

Step 2: CNC Operation & Calibration & Sowtware Setup

After finishing the design, I moved to the preparation stage for the machine.

File Import: I exported my design as a DXF file and loaded it into ArtCAM.

The Process: As seen on the screen, I imported the vectors to define the cutting paths. At this stage, I assigned the 0.4 mm tool parameters and calculated the final G-code.

Importing DXF vectors into ArtCAM to generate toolpaths.

Turning pixels into sawdust! Before pressing "Start", I had to calibrate the machine to the physical material.

1) Stock Measurement & Setting Points Precision starts with manual measurement. I used a tape measure to find the exact length and width of the plywood sheet. Next, I performed the Setting process:

I gave the machine the specific coordinates (points) for the work area.

I moved the spindle to the corner of the sheet to set the Work Home (X and Y zero points). This ensures the design is perfectly positioned on the physical board and won't cut outside the material.

2) Securing the Stock I used screws to fasten the white-laminated plywood to the sacrificial bed. This prevents any shifting while the machine follows the complex "puzzle" toolpaths with the 0.4 mm bit.

[: Plywood secured and calibrated on the bed] Calibration stage: Measuring the stock length and setting the work home coordinates.

Step 3: Launch & CNC Operation

With the coordinates set and the material secured, I launched the machine:The Tool: I used a high-precision 0.4 mm bit.The Process: I monitored the spindle as it executed the G-code. The fine bit and the 0.35 mm tolerance worked together to create incredibly sharp, clean edges on the laminate.

Step 4: Assembly Process

Text:

"As you can see, I am now assembling the table. The parts fit together perfectly like a puzzle. Because the design was calculated so accurately, I don't need any glue, nails, or screws to hold the pieces together. Everything stays in place just by the way the parts interlock with each other. It is very fast and easy to put together or take apart."

Step 5: Stability & Load Test (40 kg)

Text:

"After finishing the assembly, I conducted a stability test to see how much weight the table could handle. I placed a 40 kg load on top of it. Even with this heavy weight, the table remained completely stable and did not wobble. This proves that the 'puzzle' legs and the 10mm plywood are strong enough to be used as a real workstation."

Conclusion

"This project successfully demonstrates the full cycle of large-format CNC production. By moving from a digital 2D sketch in Onshape to a physical object, I proved that precision engineering can replace traditional assembly methods.

The most important result of this work is the stability and modularity of the design. The table stands perfectly without any glue or screws in the joints, yet it is strong enough to pass a 40 kg load test with zero issues. This 'Puzzle Table' is not just a furniture piece, but a scalable system that can grow into a 1-meter or 1.5-meter workstation depending on the user's needs."

✅ Project Final Checklist: 2D Design: Completed in Onshape.

CAM Workflow: Vectors imported and toolpaths generated.

CNC Operation: Material secured with screws and zeroed manually.

Assembly: 100% glue-free interlocking joints.

Strength Test: Passed (40 kg capacity).