Juan Carlos Miranda Castro

FabAcademy - 2017

Costa Rica - St. Jude School


Computer-controlled cutting

    Group assignment
  • Make lasercutter test part(s), varying cutting settings and slot dimensions.

  • Individual assignment
  • design, make, and document a parametric press-fit construction kit, accounting for the lasercutter kerf, which can be assembled in multiple ways.
Learning outcomes
  • Demonstrate and describe parametric 2D modelling processes.
  • Identify and explain processes involved in using the laser cutter.
  • Develop, evaluate and construct the final prototype.
Have you
  • Explained how you parametrically designed your files.
  • Shown how you made your press-fit kit.
  • Included your design files and photos of your finished project.



Laser cutter - CAMFive CFL-CMA 1200

Vinyl cutter - MH-365 Series





openSCAD (3D CAD modeller)

Inkscape (vector graphics)

LibreCAD (Open Source CAD)

Rhino (3D modeler)

SmartCarve (laser cutter software)

CorelDRAW (vector graphics)

Tinkercad (online 3d cad design tool)

Sure cuts (design and cut software)



3mm MDF

3mm cardboard

Laser cut tests

  • Laser cutter settings:
  • 3 mm MDF: max power: 75, min power: 65, speed: 17 mm/s
  • 2 mm acrylic: max power: 65, min power: 55, speed: 17 mm/s
  • Slot dimension test

    I designed a solt test for 3 mm MDF and 2 mm acrylic. Using LibreCAD I made different slots, from 3 mm to 2,5 mm on the MDF, and from 2 mm to 1,5 mm on the acrylic.

    mdf slot
    acrilico slot

    For the MDF material, the best fit was with the 2,9 mm slot.

    2,9 mm

    For the acrylic material, the best fit was with the 1,8 mm slot.

    1,8 mm
  • Kerf test

    For the kerf test, I used LicreCAD to make two samples. The first has parallel horizontal cuts every 4 mm. The secon has the same pattern but every 2 mm.

    kerf prueba

    The first test was very quick to cut, but did not bend very much. It made only a smal curve:

    kerf prueba 1

    The second test was much slower to cut, but it bends more than 180°.

    kerf prueba 2

Group assignment

  • As a group assignment, we had to design, laser cut and assemble a piece of furniture. We chose to make a laptop stand and used Rhino software for the modelling.

    Since the material to be used is cardboard, it needs enough layers to hold the weight of a laptop. It has 10 legs and 9 horizontal connectors.

    perfil del modelo

    Each slot has a chamfer for easier assembly


    Finally the pieces were laid out for cutting.


Laser cut the model

  • The laser cutter works with the software SmartCarve, and it accepts .plt files, so, we had to open a pdf or svg file with corelDRAW and export it to plt.

    Then, the file is imported into SmartCarve, and the settings must be configured according to the material. For cardboard cutting the settings are:

      Maximum power: 35

      Minimum power: 30

      Velocity: 30

    Then, we turned on the machine and set the height of the head to 6mm, and set the origin to one of the corners of the material.

    encendido laser

    modelo cortado

Assembling the model

  • All the pieces were assembled into place, and we tested the model with a laptop.

    modelo armado

    The entire process can be seen on the video:

Press-fit kit

  • For the process of designing the press-fit construction kit I started with a quick idea sketched with tinkercad, and then I made the parametric design with openSACD.

    The model is a simple design with four conectors distributed at 90° angles. Eventually, with the help of Robert, I added another piece with a larger slot connector to overlay two pieces, wich resulted in four conectors distributed at 90° angles but in a different plane.

  • I started with the tinkercad sketch:

Parametric openSCAD press-fit kit

  • First, the vertical axis of the piece is formed with the command:


    Then, other shapes are added (green, blue and red shapes), and this group of pieces is duplicated and rotated 90° to form the horizontal axis:

    openscad model

    The color shapes are subtracted from the yellow shapes (axes) to get the final model:

    openscad model

    The model can be extruded, copied and rotated to simulate a connection between two pieces.

    openscad model

    Finally, openSCAD has the option to render and export the model to svg format, for later layout and laser cutting:

    openscad model

    Zoomed in region for detailed view:

    openscad model
  • For the second piece of the construction kit, the first model was used as template:

    openscad model

    In this case, the two big axes' rectangles had to be joinded before the rest of the model was scripted. This is the command:


    Then, the smal shapes of the vertical axis were modified to create the central coupling, again by sbtraction:

    Again, the model can be extruded, copied and rotated to simulate a connection between two pieces.

    openscad model

Cutting the press-fit kit

  • The model was then exported to svg format, for later layout and laser cutting.

    At this point, there are still two steps to complete before sending the model to the laser cutter:

      first, the file was loaded in Adobe Illustrator and converted to *.PDF,

      after, that pdf was loaded in CorelDRAW and converted to *.PTL.

    The PTL file was then loaded in SmartCarve, and all the settings were configured. I used 3mm MDF for this model, so the configuration for the machine is:

      Maximum power: 55

      Minimum power: 50

      Velocity: 12

    After setting up the configuration, I turned on the laser cutter:

    Then, the model was cut:

    Some pieces qere not fully cut, so, for future works, I will adjust the machine settings (increase power or lower velocity).

    And this is the final model:

Cutting vinyl

  • I chose the school logo for this assignement.

    The cutter software can import png files, so I had no need to convert my file. I used the otion "trace image" available in the Sure Cuts sfotware. After changing the contrast value a little, I found the right value to trace my image:

    Then, I turned on the plotter and prepared the material for cutting:

    • the material must be well aligned (perpendicular to the machine).
    • the pinch roller release levers must be lowered to secure the material.

    The PTL file was then loaded in SmartCarve, and all the settings were configured. I used 3mm MDF for this model, so the configuration for the machine is:

      Maximum power: 55

      Minimum power: 50

      Velocity: 12

    Then, form the computer, the print command is sent:

    My first test did not work very well because the letters at the bottom were too small, so I cut a second model:

    Then, I removed the outer parts of the sticker, and placed the final model on a piece of transfer tape: