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3. Computer controlled cutting

Group assignment:

  • Characterize your laser cutter's focus, power, speed, rate, kerf, and joint clearance.

To see our group assignment click here

Individual assignments:

  • Design, lasercut, and document a parametric press-fit construction kit, which can be assembled in multiple ways. Account for the laser cutter kerf.

  • Cut something on the vinyl cutter.

1. Parametric design

Parametric design allows us to easily modify certain dimensions of a model without deforming the overall geometry. This approach is ideal for designing a press-fit construction kit, where precision and adaptability are essential.

For this project, we chose Freecad as our CAD software.

Software Installation

  • Once the file is downloaded, open it and follow the installation steps until completion.

  • Launch FreeCAD, click on "File", then "New".

Creating the Parametric Model

  • From the workbench drop-down menu, select “Spreadsheet”, then click “Create a new spreadsheet”.

  • Enter the parameters and values shown below (material thickness, kerf, slot width, etc.).

  • Switch to the “Part Design” workbench. Click on “Create Body”, then “Create Sketch”. Select the XZ Plane (Base Plane) and click OK.

  • Use the Rectangle tool, select Centered Rectangle, and place it at the origin of the sketch. Click once, move the mouse, and enter the length and width values as shown below.

  • Use the rectangle tool again to draw a second rectangle with the specified dimensions.

  • Click on the “Constrain coincident” tool and apply constraints to the lines highlighted in red until you obtain the result shown below.

  • Select the “Dimension” tool and click on the line highlighted in blue. Click the button highlighted in red and enter the expression underlined in red, then click OK.

This expression defines the slot width as: Material thickness − kerf

  • After watching several tutorials, we realized that assigning aliases to spreadsheet cells makes calculations easier and improves model readability.

  • Once all constraints are defined, we obtain the final parametric sketch shown below.

  • To verify our work, we modified the parameter values and confirmed that the geometry updated correctly.

  • Finally, select the sketch, click File > Export, choose the .DXF format, and save the file.

2. Laser Cutting

For laser cutting, we used the EPILOG Laser EDGE 36.

  • Open Inkscape, go to "File > Open", select the previously generated DXF file, and click "Open". A dialog box will appear—click "OK".

  • Go to File > Print, select Epilog Engraver, then click Print.

  • The Epilog dashboard will open with the design. Adjust the parameters highlighted in red and move the design by 2 mm on both the X and Y axes, as shown below.

  • Turn on the machine using the ON/OFF switch highlighted in red.

  • Place the MDF board on the machine bed as shown in the photo.

  • Once the machine is powered on, connect it to the PC and click Print.

  • Since the fume extractor is connected to a power strip, we turn it on before starting the cut.

  • On the machine’s touchscreen, press the button highlighted in red to start the laser cutting process.

Hero shots 😊😊😊

During the assembly of our press-fit kit, we did not encounter any particular difficulties. A slight amount of force was sufficient to assemble the parts properly. As shown in the photos below, the structure holds firmly without coming apart.

We can therefore conclude that both the cutting parameters and the parametric design were well chosen.

Vinyl Cutting

The vinyl cutting machine used in our lab is the Roland GS-24.

  • We chose to cut the design shown below. For more details on using Inkscape, refer to Week 2.

  • On the machine, lower lever "#1" to load the vinyl. Move the rollers "#2" to the edges of the vinyl, ensuring they are positioned within the white zones "#3", then raise lever "#1".

  • Turn on the machine by pressing the button highlighted in orange once, then press the button highlighted in blue once, and finally press ENTER. The machine will display the vinyl width as shown below.

  • Connect the machine to the PC using a USB cable.

  • In Inkscape, go to File > Print and select Roland GS-24.

  • Click on Preferences. In the new window, click Get from machine to retrieve the cutting dimensions. Then set the length to 65 mm (the height of our design) so the cutter starts from the correct position.

  • Click Print. You should obtain the result shown below.

hero shots 😊😊😊

Files