Week 3 – Computer-controlled cutting
Fab Academy 2026 · Jenny Rojas · Industrial FabLab UCuenca
1. Checklist
- ✅ Linked to the group assignment page
- ✅ Reflected on my individual page what I learned from the lab safety training
- ✅ Explained how I created my parametric design
- ✅ Documented how I made my press-fit construction kit
- ✅ Documented how I made something with the vinyl cutter
- ✅ Included my original design files
- ✅ Included hero shots of my results
2. Group Assignment
For the group assignment, the lab characterized the laser cutter by analyzing key parameters such as focus, power, speed, kerf, and material behavior. This collaborative work allowed us to understand how different configurations affect cutting quality, engraving definition, edge finishing, and dimensional precision.
During the characterization process, different tests were performed to compare how the machine responds to changes in speed and power. These tests were important because they helped us identify the most appropriate settings for cutting MDF accurately while reducing excessive burning, incomplete cuts, and dimensional errors.
The results obtained from this characterization directly supported the individual development of the press-fit construction kit presented on this page. Understanding the kerf value and the behavior of the material allowed me to define better tolerances, improve the fit between parts, and achieve a stable assembly without glue.
Open Group AssignmentDesigning a Parametric Construction Kit
1. Project Overview
For the construction of a parametric-based kit, Fusion 360 was used as the main design software. The construction model is based on a modular, interlockable link system designed with press-fit joints that follow precise KERF parameters.
The main objective was to create a construction kit that could be assembled without glue or screws. For this reason, the design needed to consider material thickness, kerf compensation, joint tolerance, and structural stability.
Fabrication was carried out using a 90W CO₂ laser cutting machine available at the Industrial FABLAB, working with MDF material.
2. Initial Sketch and Construction Plan
The design process starts from a construction plan using a curvilinear drawing approach. An initial hand sketch was created on paper to define the basic geometry and dimensions of the assembly links before digital modeling.
This first sketch helped me visualize the possible shape of the pieces and understand how the elements could connect to each other. The idea was to create a flexible modular system that could be repeated and combined in different configurations.
3. Kerf Calculation
To ensure a proper press-fit assembly, the kerf of the laser machine was calculated using a power and speed combination table. The best result was obtained with the following parameters, using the NEXTION equipment:
- Power: 40 watts
- Speed: 40 mm/s
- KERF: 0.05 mm
These parameters were selected because they provided a clean cut and acceptable dimensional accuracy. The kerf value was later included in the Fusion 360 parameters to adjust the joint dimensions and improve the final assembly.
4. Parametric Variable Definition
Once the kerf value was defined, all key variables were parametrized in Fusion 360 to allow flexibility when changing material type, thickness, or machine calibration.
- KERF = 0.05 mm
- h = MDF material thickness – 4 × kerf
- Assembly height = 15 mm
- y = assembly height + kerf
The link geometry was designed within a 60 × 60 mm working area.
Using parameters in Fusion 360 was very useful because any change in material thickness or kerf value could automatically update the model. This reduced the risk of errors and made the design more adaptable for future fabrication tests.
5. Parametric Joint and Notch Design
With the base geometry defined, the notches for the joints were drawn using a fully parametric approach. This allows the joint dimensions to be adjusted automatically if the kerf, material, or thickness changes.
The notches were designed to generate enough friction between parts while still allowing manual assembly. This balance is important in press-fit systems because the parts must hold together firmly without breaking or becoming too difficult to assemble.
6. Tolerance Referencing
All notches were referenced sequentially using the defined parameters and tolerances, ensuring repeatability and a consistent press-fit behavior throughout the assembly.
Tolerance referencing helped maintain the same joint behavior in all repeated elements. This is especially important in modular kits, where each piece must connect correctly with the rest of the system.
7. Crossbar Design
The crossbars that support and connect the structure were designed next, using the same parametric variables defined for the main link, maintaining coherence across the system.
These crossbars provide additional stability to the final assembly. Their dimensions were also linked to the parametric values to ensure that they could adapt to changes in material thickness and kerf compensation.
8. Material Thickness Simulation
A simulation was performed using a 5 mm thick material to validate the parametric behavior of the design before fabrication.
- KERF = 0.05 mm
- Material thickness = 5 mm
This simulation was useful to verify how the model would react if the material thickness changed. It confirmed that the parametric structure was working correctly and that the design could be adapted without redrawing the complete geometry.
9. Final Fabrication Setup
After validating the design, final fabrication was prepared by calibrating the laser cutter, paying special attention to the focus height.
The MDF sheet was placed on the machine bed, and the focus distance was adjusted before sending the job. The cutting file was checked to confirm that all lines were correctly defined and that there were no duplicated curves that could affect the cut.
10. Final Assembly and Results
Once all parts were cut, the final assembly was carried out. The resulting product shows a strong press-fit behavior, correct kerf compensation, and does not require glue, which was a key requirement for this practice.
The final result confirmed that the parametric design strategy was effective. The pieces assembled correctly and maintained structural stability due to the friction generated by the press-fit joints.
This process also demonstrated the importance of testing, calibration, and iterative design in digital fabrication. By adjusting the kerf and tolerances, it was possible to improve the final fit and obtain a cleaner assembly.
11. Downloadable Files
12. Conclusion
The use of parametric design for press-fit assemblies enabled the development of a flexible construction kit adaptable to different materials, thicknesses, and kerf values. Proper laser calibration and variable definition resulted in a stable, glue-free assembly, fully meeting the objectives of this Fab Academy assignment.
This assignment helped me understand the connection between digital design and physical fabrication. The final result depended not only on the CAD model, but also on machine calibration, material behavior, safety procedures, and the correct interpretation of kerf compensation.
Through this process, I learned that computer-controlled cutting requires continuous testing and adjustment. Small changes in parameters can significantly affect the final result, especially when working with press-fit systems that require precision.
Vinyl Cutting Assignment – Logo Design and Fabrication
As part of this weekly assignment, we focused on the design and fabrication of custom logos using vinyl cutting techniques. The objective was to create and produce representative logos for each team and lab: Starlabs from Universidad Politécnica Salesiana, Industrial FABLAB from Universidad de Cuenca, and ZOILAB.
This activity allowed us to apply subtractive manufacturing processes on flexible materials such as adhesive vinyl, combining digital design with physical production. It also helped us understand the importance of preparing clean vector files, configuring the machine correctly, and carefully applying the final vinyl pieces.
Design Preparation
Each logo was designed in vector format using CAD software, ensuring all elements were properly defined as clean paths. Since vinyl cutting requires vector geometry, special attention was given to eliminating duplicate lines and ensuring closed contours. The final designs were exported in compatible formats such as SVG or DXF.
The design preparation stage was important because the vinyl cutter follows the vector lines exactly. Any open contour, duplicated line, or unnecessary node can affect the quality of the final cut.
Machines Used
- Vinyl Cutter: Used to precisely cut the vector designs onto adhesive vinyl.
- Plotter: Used to support visualization and layout verification of the designs before cutting.
Machine Setup
- Loading the vinyl roll into the machine
- Adjusting pinch rollers to secure the material
- Setting the origin point
- Configuring cutting parameters (speed and force)
Cutting Process
The design was sent to the vinyl cutter, where the blade precisely followed the vector paths. Care was taken to ensure the cutting depth was sufficient to cut the vinyl layer without damaging the backing material.
The cutting force and speed were checked before the final cut to avoid tearing the vinyl or producing incomplete cuts. This step was especially important for small details and thin lines in the logos.
Weeding Process
After cutting, the excess vinyl was removed manually in a process called weeding. This step requires precision to avoid lifting small or detailed parts of the design.
The weeding process was performed carefully using manual tools. Removing the unnecessary vinyl helped reveal the final shape of the logos and prepared them for transfer.
Application
Transfer tape was applied over the design to facilitate placement. The vinyl was then transferred onto the desired surface, ensuring proper alignment and adhesion.
This assignment demonstrates the workflow from digital design to physical output using a vinyl cutter, highlighting precision, material handling, and finishing techniques. The process also showed how vinyl cutting can be used for branding, signage, personalization, and visual communication inside a FabLab environment.
Hero Shot
The following hero shot presents the final result of the vinyl cutting assignment developed during Week 03. This activity focused on the fabrication of customized institutional logos using adhesive vinyl and computer-controlled cutting technologies.
The final application demonstrates the precision achieved through vector-based design, machine calibration, material preparation, and careful weeding and transfer processes. The logos of the different laboratories were successfully fabricated and applied, obtaining clean edges, accurate details, and a professional finish.
Through this assignment, important skills related to digital fabrication workflows, subtractive manufacturing,
vinyl material handling, and graphic production were reinforced within the context.
Group Work Conclusion
The group assignment was essential to understand how the laser cutter behaves under different working conditions and how each parameter directly affects the final quality of the cut. By testing focus, power, speed, kerf, and material response, the team was able to identify the most appropriate configuration for working with MDF in a precise and controlled way.
This collaborative characterization allowed us to compare results, analyze cutting defects, observe burning effects, evaluate dimensional accuracy, and define reliable values for future fabrication processes. The kerf measurement was especially important because it provided a technical reference for designing press-fit joints with better tolerance and stability.
As a result, the group work strengthened the connection between machine calibration, material behavior, and digital design decisions. The information obtained during the tests supported my individual assignment and helped me improve the parametric construction kit, achieving a more accurate, repeatable, and functional assembly.