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Computer-controlled cutting

Week 3

Group Assignment

As a group, we decided to do some tests on the laser machine.

First, we designed CAD models to cut the machine and check the power of the cut and find out the minimum power to cut a 3mm thick MDF board..

Then we designed other models in CAD to test the laser burn tone, depending on the power and speed of the machine.

With this we manage to have a physical example of the color shades and cutting depth that we can use in our designs.

The examples we can see below:

In addition to the previous examples, we also decided to make some experiments to verify the fittings of two types of materials: 5mm thick card and 3mm mdf wood

For each we did 3 examples.

  • Fit: accurate to 3mm (thickness equal to material thickness)
  • Fit: 3.1mm (thickness 0.1mm wider than material thickness)
  • Fit: 3.2mm (0.2mm thick in relation to the thickness of the material)

  • Results:

    The 3mm socket was wide and the pieces did not attach to each other

    The 3.1mm fitting was good, but the fit that best made the pressfit so that the pieces fit nicely is 3.2mm.

    Parametric . press-fit design

    I usually use Rhinoceros 3d software to make my 3D models.

    However in Rhinoceros there is no tool that allows to make a parametric drawing, where you define the measurements and if they are coincident, parallel, have the same value or you can change the value of the dimension of the shape without having to re-draw.

    In order to make a parametric selection in rhinoceros it is necessary to install the Grasshopper that is a graphical algorithm tightly integrated with Rhino's 3-D modeling tools.

    The installation is free and you can find out more from the site:

  • Grasshopper

  • I installed the grasshopper and saw some tutorials to figure out how it works. However I did not like the way the program worked, I was not used to it and found it difficult.

    So I gave up on this program, and started using fusion360.

    Fusion 360

    Fusion 360 is the name 123design, and works from the same principle as solidWorks.

    Find out more about fusion360:

  • fusion360

  • Since the drawing I wanted to make was a box, it was easy to start on a new program.

    I started by doing a sketch without measures of the sides of the box that wanted to cut in the laser.

    I drew the side grooves of the box, making a rectangle and corendo with the trim tool, the edge that I did not want. So I built a kind of "teeth" on the side of the box.

    Then I went to "modify" and clicked on "change parameters" that opens a box where it allows me to define the measurements I want to use a parameter, which can be changed.

  • I added the cut depth that matches the thickness of the material
  • And the cut size that correpsonde to the size of the flaps of the fittings.

  • Then go to the sketch and define the dimensions of the drawing, with the parametric measurement we defined above.

    I repeated the same process to the 5 sides of the box, and then I exported the sketch to vector, .dxf and .ai format

    lasercutter . individual

    In the previous week I drew the 3D drawing of the box that I would like to use for my project.

    This week, I started by exporting the 3D Design from Rhinoceros 3D to Adobe Illustrator, where all the planning of my drawing became 2D, vectorial and editable.

    After having my planning with the measurements, I started with the CorelDraw program to be able to print on the lasercutting machine.

    On CorelDraw it was necessary to:

    1. Define the page size equal to the maximum measures of the machine, which are 600mm x 300mm.

    2. Define the minimum line thickness for the laser cut to be as precise as possible.

    3. Define and paint the areas that will be to burn and not to cut with black solid color, RGB: 0,0,0

    4. Finally, set the cut and burn parameters in the print preset.

    Before starting to cut, I decided to do a few small tests on the material first (figure on the right) to understand the parameters of speed and power needed to cut each type of material.

    lasercutter . process

    For my first tests of my box design, I decided to include three types of materials:

  • cardboard
  • acrylic
  • wood

  • To cut the Cardboard I used for as:

      Vetor Setting:
    • Speed: 10%
    • Power: 40%
    • Freq: 500 Hz

      Raster Setting:
    • Speed: 100%
    • Power: 20%

    To cut the MDF wood I used for as:

      Vetor Setting:
    • Speed: 12%
    • Power: 100%
    • Freq: 500 Hz

      Raster Setting:
    • Speed: 60%
    • Power: 60%

    To cut the acrylic I used for as:

      Vetor Setting:
    • Speed: 10%
    • Power: 100%
    • Freq: 5000 Hz

    The cuts and the fittings were fine, and the pieces fit perfectly to assembly the box. I used white glue to help fix the pieces

    To ensure that the parts are secured without glue, it is necessary to reduce 1mm on each side to the fittings. For example, if the thickness of the material is 3mm, the fittings should be 2.98mm to get stuck.

    construction kit . pressfit design

    For my construction kit I decided to make a sphere divided into 6 parts, as can be seen in the figure on the side.

    I started by designing the model and then cutting with the tool "split" the parts that joined, so that the fittings were made and then the pieces fit one of the others.

    Then I put all the pieces of the sphere in the same plane and removed the outer lines related to the drawing of the piece.

    I exported the drawing of the file in dxf. and I cut it in the laser machine, as I did before with my box.

    Then I removed the pieces and began to join them.

    The idea of this sphere that I made, is that the pieces can be united in different holes of fit.

    By joining all the pieces we are going to give the shape of a sphere, but they can be united in different ways, for example to make a kind of "ribs" or "skeleton".

    During the construction the pieces were well joined to each other and by compression does not dissolve.

    The effect of the piece was fantastic!

    This can be a decorative piece or even come to make of lamp in a room or room.

    And each person while building this kit can give their personal touch and build the sphere differently.

    Find the files used and download here:

  • week3_contruct.AI _ illustrator file
  • week3_contruct.kit.cdr _ CorelDraw file
  • 6 pieces of Sphere_kit_base_x6.stl _ STL file
  • 4 pieces of Sphere_kit_small_x4.stl _ STL file
  • 4 pieces of Sphere_kit_medium_x4.stl _ STL file
  • 4 pieces of Sphere_kit_large_x4.stl _ STL file

  • The following images show various positions of this construction.


    I decided to give a name and create a logo for my project. Which will be called "Plant.Air".

    I used the logo and cut it on vinyl to customize the boxes I did before in laser cut.

    To do this, I used my vectorized logo in the Illustrator program and imported it into the PLOT software that works with acutting plotter ROHS.

    In PLOT software it is necessary to define:

  • Overcut: 1mm
  • Curve flatness: 0.6 auto-align

  • Speed: 350 m m / s
  • Force: 60g

  • After the cut was done, the logo was removed and pasted into cardboard and MDF wood cartons.

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