II. Individual Assignments

II.1. Choosing the Material

First, I characterized the material I would use to create my parametric construction kit. For this, I chose MDF (Medium Density Fiberboard), a composite material made of wood fibers and synthetic resins, characterized by its homogeneous structure and smooth surface. It is the standard in digital fabrication for prototyping due to its isotropy, which allows for precise cuts and uniform engravings without the irregularities of natural wood grain. Its dimensional stability makes it ideal for validating mechanical assemblies and press-fit structures before moving to final materials. The MDF material I used had a thickness of 2.6 mm.

Image 5: Measuring the thickness of the MDF material with a vernier caliper.

II.2. Designs and Tests

Calculating the kerf (cutting compensation) is the width of material that the laser "eats" as it passes over it. If you want a piece to fit into a hole, you must compensate for this loss. The basic formula is: Final Measurement = Desired Measurement + Kerf For this group test, we designed a comb file to test the fit. Since we already had the material thickness measurement of 2.6 mm, we increased and decreased it in 0.1 mm increments until we obtained eleven divisions, ranging from 2.0 to 3.0 mm. To design the comb file, I used Autodesk Fusion. I had to be very precise with the measurements to avoid failure. I started with the comb lines, which had to have different widths ranging from 2.0 to 3.0 mm.

Image 6: Comb design to check the fit, which was very helpful for building my parametric construction kit.

Image 7: Once the comb design was finished, I exported it as a DXF file, since this is the format accepted by the laser cutting machine software (RDWorks).

Image 8: Once the RDWorks program was downloaded and opened, the comb file was imported to configure the speed and power, as well as the order of the engraving and cutting layers.

Image 9: The file was duplicated, and the engraving letters were added, including the thickness and type of material, along with the FAB LAB PERÚ logo.

Image 10: The engraving and cutting power and speed were configured. For engraving, the speed was set to 250 mm/s and the power to 25%, and for cutting, it was set to 25 mm/s and the power to 55%. The configuration was then saved to a USB drive and taken to the laser cutting machine.

Testing a laser machine is important to ensure it functions correctly and that the settings are appropriate for the specific material and job. The power and speed must be adjusted for each type of material to be used. In my case, I based my settings on tests performed in a group. The laser height relative to the material must also be adjusted. For this, a 3D-printed step-shaped calibrator was used on the third level.

Image 11: Laser distance calibration to the material

Image 12: Comb result; first, it was sent for engraving and then for cutting.

Image 13: Testing the fit

Designing the Construction Kit

For the development of my parametric kit, I used Fusion 360. I worked with 2.6mm thick MDF. The parametric shape I used was a hexagon. To do this, I first defined the parameters. Using parameters in Fusion 360 allows me to define the model's geometry using mathematical variables instead of static values. By creating a "Parameter Table," I can assign names to critical dimensions, such as the material thickness (mdf_thickness) or the kerf and tolerance. This methodology is fundamental in digital manufacturing, as it allows the entire design to be automatically updated if I decide to change materials or if fit tests indicate that tolerances need adjusting. Instead of redrawing each piece, I simply modify the numerical value in the table, and the model's logic adjusts the pieces, grooves, and assemblies consistently and precisely.

Image 14: Defining parameters with mathematical equations that can then be modified and adapted to the material used for cutting.

Image 15: I create a hexagon and draw it from the center.

Image 16: In the measurements, I define the uploaded parametric dimensions by name.

Image 17: Then I draw a rectangle with the wood thickness as the width and 20% of the total diameter as the length to achieve a good fit.

Image 18: The created rectangle is moved to the center of one of the sides of the hexagon.

Image 19: A circular pattern is created from the rectangle to be replicated on all sides of the hexagon.

Image 20: The circular pattern is created; now we have the rectangles for the cuts on each side of the hexagon.

Image 21: Creating a chamfer for a better fit of the laces. It's not clear to me where the chamfer should be positioned.

Image 22: Since I didn't know where to create the chamfer, I did it on the inner and outer part of the rectangle.

Image 23: Once the parametric drawing was finished, it was exported as a DXF file to be sent to the RDWorks program for configuring the cutting speed and power.

Image 24: Once the RDWorks program was opened, the DXF file obtained in Fusion was imported.

Image 25: Several copies were made, and the cutting speed and power were programmed to 25 mm/s and 55% power.

Image 26: The file was saved to a USB drive to take to the cutting machine.

Image 27: The cut was made. I tested one to check if the cut actually went through all the material, and it turned out very well.

Image 28: The finished pieces. I was eager to fit them together and see their fit and strength. The fit was very good in most joints, but in some, it was loose. I still don't understand why.

Image 29: Testing its strength and stability, I realized it can have many uses with a little imagination.

Inspiration and Restoration of a Vinyl Cutter

During this stage at the Fab Academy, I've had the opportunity to closely observe the restoration process of a Roland vinyl cutter that was destined for disuse. My colleague took on the challenge of reviving this machine, which had issues with drivers incompatible with Windows 11 and a lack of original cables. Seeing how he overcame these technical barriers through research and perseverance has served as a fundamental guide for me to understand that "obsolete" hardware only needs the right knowledge to become valuable again.

Image 30: Understanding the operation of the vinyl cutter after its restoration.

This restoration process was especially inspiring for me because in my lab, Fab Lab Madre de Dios, we have a machine that has the exact same connectivity and driver problems. Observing the successful setup and workflow to make it operational has given me the confidence to return and lead the commissioning of our own equipment. It's a valuable lesson about the importance of documentation and knowledge sharing within the Fab Labs network.

Image 31: Using Cut Studio software to design a cute little butterfly.

To test the now-operational equipment, we worked on the design of a butterfly, a symbol I plan to bring to my region. The design was prepared in a vector workspace, carefully considering each node to ensure a smooth cut. Seeing the finished file on screen after the initial technical issues was a key moment, as it demonstrated that the integration between the modern software and the refurbished machine was finally stable and functional.

Image 32: Importing my butterfly drawing, which was in JPG format.

Image 33: Refining the image to obtain precise vectors for cutting on the vinyl cutter.

Image 34: Butterfly ready to be cut.

The physical testing phase was equally revealing. After several attempts where the cut wasn't perfect, technical adjustments were made until the ideal blade force (80) was found. This calibration allowed the butterfly to be cut perfectly, without damaging the vinyl backing. Understanding this relationship between the digital parameters and the physical response of the blade is the knowledge I now feel capable of replicating when I return to Madre de Dios to set up our cutter.

Image 35: Butterfly finished, after removing the extra vinyl that wasn't part of the design. I used black because that's what was available.

The final result was a butterfly with precise and detailed cuts, ready to be weeded and applied. This experience has left me very excited; I've not only learned to design and cut, but I've also acquired a mindset of technical problem-solving. Now I have a clear goal: to apply this entire workflow at the Fab Lab Madre de Dios to get our machine up and running, transforming an unused piece of equipment into an active tool for my community and my final project.

Image 36: A laptop decorated with many butterflies and the Madre de Dios brand.