Week 08 | Electronics Production
Group Assignment
This week's group assignment consisted of characterizing the PCB fabrication process using the equipment available in the laboratory. The objective was to understand the workflow for producing printed circuit boards, including milling the copper traces with a CNC machine, drilling the component holes with a bench drill, and cutting the board using a manual shear cutter. The activity was carried out in the Electronic Laboratory of the Pontificia Universidad Católica del Perú (PUCP).
The complete documentation of the group work can be found in the following page:
Group assignment documentation
Individual Assignment — Week 08
During this week the complete process of fabricating, assembling, and testing a printed circuit board (PCB) was carried out in the electronic laboratory of the Universidad Católica del Perú - PUCP. The objective was to understand the full digital fabrication workflow for electronics, from the design files to the final functional board.
1. Preparing the PCB Design
The first step consisted of preparing the PCB design created previously in KiCad. Before exporting from KiCad as an SVG fileAdditionally, the trace width was adjusted to 1 mm in order to ensure that the milling tool could properly isolate the circuit traces. Then, the board layout was exported from KiCad as an SVG file. This vector format allows the circuit traces to be edited and prepared for the CNC milling process. The SVG file was then opened in Inkscape, where several adjustments were made to prepare the file for fabrication.
First, the image was mirrored (inverted) to ensure the circuit would be correctly oriented when milled on the copper board. Another important modification was related to the ground plane. In this design, the ground was not routed as a separate trace because the entire copper board was used as a ground plane. For this reason, in Inkscape some of the circuit paths were slightly opened so that the ground connections could properly merge with the rest of the copper surface.
2. Generating the G-code
Once the design was properly prepared, the next step was to generate the G-code, which contains the instructions that control the CNC milling machine.
The G-code defines the movement of the tool, including the path that the milling bit must follow to remove copper and isolate the circuit traces. Before starting the machining process, the toolpath was verified in the CNC software to confirm that the milling paths corresponded correctly to the circuit design.
3.PCB Milling
To fabricate the board, a Genmitsu CNC milling machine was used. This type of machine is commonly used in digital fabrication laboratories to produce PCB prototypes.
The copper board was securely fixed to the machine bed to prevent any movement during the milling process. A V-bit engraving tool was installed in the spindle, which is suitable for removing copper around the traces.
Once the machine was configured, the milling process began. During this stage, the machine removed the copper surrounding the circuit traces, creating the electrical pathways of the PCB. This process demonstrates how digital toolpaths are translated into physical circuits.
4. Drilling and Cutting the Board
After the milling process was completed, the board was removed from the CNC machine and the required holes for the electronic components were drilled.
A bench drill was used for this task in order to achieve precise and controlled holes for the component leads.
Once the drilling process was finished, the board was cut to its final shape using a manual shear cutter.
In this case, the PCB was trimmed into a hexagonal shape, which is part of the visual design of the electronic module.
5. Cleaning the PCB
Before assembling the components, the PCB was cleaned using isopropyl alcohol and a brush. This step removes copper dust, grease, and residues from the milling process, ensuring good electrical contact during soldering.
6.Component Assembly and Soldering
The next step was the assembly of the electronic components. The components used in this board include resistors, pin headers, LEDs, buttons, and the Seeed Studio XIAO ESP32-C3 microcontroller, which serves as the main controller of the circuit.
All components were soldered manually using a soldering station, solder wire, and cutting tools to trim the excess leads.
During the soldering process, special care was taken to control the temperature of the soldering iron and apply the correct amount of solder in order to avoid cold joints or unwanted bridges between traces.
7. Electrical Verification
After completing the assembly, the circuit was tested using a digital multimeter and a power supply.
The verification process included checking the continuity of the traces, verifying the correct voltage supply, and ensuring that no short circuits were present. These tests confirm that the PCB was correctly fabricated and assembled before running the microcontroller program.
Reflection
This activity provided a complete understanding of the PCB production workflow in a digital fabrication laboratory. The process integrates several stages including electronic design, vector file preparation, CNC milling, manual assembly, and electrical testing. Working through each of these steps helped develop practical skills in digital fabrication, electronics manufacturing, and safe machine operation.
Download Files
The design files used in this assignment can be downloaded below.
