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7. Large format CNC (computer controlled Machining)

CNC Machine

A large format CNC (Computer Numerical Control) machine is a high-precision, automated tool used for cutting, carving, or milling large sheets of material such as wood, metal, plastic, or composite materials. These machines are controlled by computer programs that precisely guide the cutting tools, allowing for complex designs and patterns to be executed with great accuracy. Large format CNC machines are commonly used in industries such as furniture manufacturing, sign making, and aerospace, where large-scale production and intricate cuts are required. Their ability to handle large materials and produce consistent, repeatable results makes them a valuable tool in modern manufacturing processes. CNC machine safety is essential to prevent accidents and ensure smooth operations.


Safety Requirements

  • Proper Training: Operators must be trained in machine operation and safety procedures.

  • Personal Protective Equipment (PPE): Wear safety glasses, ear protection, gloves, and other necessary PPE.

  • Machine Maintenance: Regularly inspect and maintain the CNC machine to ensure it is in good working condition.

  • Clean Work Area: Keep the work area organized and free of obstructions to avoid accidents.

  • Safety Guards: Ensure that safety guards are in place to protect against moving parts.

  • Emergency Stop: Operators must know how to quickly stop the machine in case of an emergency.

  • Supervision: Never leave a running machine unattended; always monitor its operation.

  • Material Handling: Handle materials carefully to avoid injury or damage to the machine.

  • Avoid Loose Clothing: Do not wear loose clothing or jewelry, and tie back long hair to prevent entanglement.

  • Proper Setup: Ensure the machine is correctly set up and materials are securely fastened before operation.

Group Assignment

To conduct a test on the CNC machine to identify its basic requirements and operations. You can view our group’s work by visiting our website here.Click Here

Individual Assignment

We were assigned the task of creating a large-scale project using a CNC machine and an MDF wood sheet. The design had to meet the following criteria and limitations:

  • Press-Fit Assembly: The design should utilize press-fit methods and wood joints for assembly.
  • Size Requirements: The product must be sizable, with at least one dimension being 90 cm or larger.
  • Material Constraints: The design must be accommodated within a single MDF sheet measuring 2440 mm in length, 1220 mm in width, and 12 mm in thickness.

Table Designing process

Using Fusion 360, I created a wooden table design to be cut on the CNC machine. Here are the steps:

  1. Go to Create Sketch, then select the Circle tool from the toolbar. Draw a circle with a diameter of 90 cm, and use the Extrude feature to extrude the design by 12 mm, as shown below.
  2. Create a new sketch and draw the table leg with adjusted dimensions. Use the Extrude tool to extrude the leg by 12 mm, as shown below.
  3. Position the leg beneath the circular base, then use the Circular Pattern tool to create three identical legs, as shown.
  4. Select the Extrude Cut tool, and drag the leg outside the base to create the desired cut.
  5. The final table design will appear.
  6. Use the Move tool to remove each piece and align them in a single plane.
  7. I use project tool and select the desired design then export it as a DXF file to imported to the CNC machine.

Click here to download file.

Cutting Process

  1. By using VCarve Pro software, i import the design file as a .DXF file into the software.

  2. Create a rectangle with a 20mm offset to ensure the cutting stays away from the MDF secure nails added for holding the material.

  3. Add a Dog-Bone Fillet to the joints that need it for a proper fit.

  4. Set the Passes value to 3, so the CNC machine will make three passes over each piece to cut through completely.

  5. Add tabs to the design to secure the pieces in place while being cut.

  6. A Material Warning pop-up will appear, indicating that the machine will cut through the material since the cut depth is set to 13mm, which is greater than the 12mm thickness of the MDF.

  7. Select the machine path to define the cutting process.

  8. After setting the requirements, i place the wood board on the CNC machine and secure its corners with screws to prevent movement.

  9. I press the start button to begin the cutting process.

  10. The CNC machine starts cutting, as shown below.



  1. These are the cut pieces of the design.

  2. I started removing the pieces, as shown below.



Filing Process

  • After removing the cut pieces, I noticed small prominences on the edges, so I used a file to smooth out the excess material.

Assembly Process

  • I inserted the table legs into the holes and assembled them, completing the final shape of the table as shown below.

Observation

  • I observed that the table legs were unstable when weight was applied to the edges, likely due to the position of the openings. To improve stability, I could either move the openings further from the center or add additional table legs. There are also several other ideas I could explore to enhance the design.

Solution

  1. I created a new leg design from the old one by extending it with an adjusted size, as shown below.
  2. I extruded the leg by 12mm and created 3 copies of it, then joined them to the base of the table, as shown below. Click here to download file.
  3. I imported the model into the CNC machine and started cutting.
  4. I removed the new table legs and assembel them into the holes of the table. This is the final shape of the table, which is now more stable than before.
Last update: January 27, 2025