WEEK 08 – Electronics Production
GROUP ASSIGNMENT — Fiber Laser PCB Characterization
Group Objective
The group assignment focused on analyzing and characterizing the fabrication capabilities of a 50W fiber laser machine for PCB production. The main goal was to understand how different fabrication parameters affect the quality, precision, and reliability of PCB traces.
During this activity, the group evaluated the behavior of the fiber laser when engraving copper-clad boards. Parameters such as power, speed, frequency, focus, and number of passes were considered in order to identify a suitable workflow for PCB manufacturing.
| Group Task | Description |
|---|---|
| Machine Characterization | Analyze the fiber laser performance for PCB fabrication. |
| Parameter Testing | Compare engraving results using different laser settings. |
| Trace Quality | Evaluate copper removal, trace definition, and isolation quality. |
| Fabrication Workflow | Define a reliable process for producing PCBs with the fiber laser. |
PCB Manufacturing: Dual Technology Approach
PCB fabrication was explored using a dual technology approach: CNC milling and fiber laser machining. This comparison helped the group understand the advantages and limitations of each process in terms of precision, speed, material removal, and final PCB quality.
The fiber laser process was especially useful for fast experimentation and direct copper engraving. However, it required careful calibration to avoid burning the substrate, leaving copper residues, or damaging fine traces.
Group assignment evidence: PCB characterization and fabrication tests using fiber laser technology.
Individual Assignment
LED Roulette PCB using XIAO ESP32-C3
This assignment focused on the complete workflow of electronics production, including PCB design, fabrication, drilling, soldering, programming, and functional validation. The project consisted of developing a custom PCB for a LED roulette system controlled by a Seeed Studio XIAO ESP32-C3.
The roulette system was designed using seven LEDs connected to independent GPIO pins of the XIAO ESP32-C3. Each LED includes a 220 Ω resistor to protect both the LED and the microcontroller from excessive current.
The PCB was designed in KiCad, fabricated using a 90 W fiber laser engraver, manually soldered, and programmed using Arduino IDE to generate the roulette animation effect.
PCB Design Process in KiCad
The PCB design started in KiCad by creating the schematic for a LED roulette controlled by the XIAO ESP32-C3. Seven LEDs were connected to independent GPIO pins, and each LED was paired with a current-limiting resistor to protect the components during operation.
After checking the schematic connections, the project was moved to the PCB editor. The XIAO ESP32-C3 footprint was placed in the center of the board, while the LEDs and resistors were distributed around it to keep the circuit readable and to support the roulette animation. The ratsnest lines were used as a guide to decide the best component placement before routing.
The traces were routed on the front copper layer, maintaining clear spacing between tracks and pads so the design could be manufactured with the fiber laser process. The board outline was then defined on the Edge.Cuts layer, and the trace artwork was exported for preparation in Inkscape.
1. Assignment Objective
Main Objective
The main objective of this assignment was to explore the complete workflow of electronics production through the development of a functional LED roulette PCB. This process included electronic design, PCB layout generation, fabrication, drilling, soldering, programming, and final validation of the circuit.
In addition, this assignment reinforced the relationship between digital design and physical manufacturing processes. Understanding how traces, pads, and component placement influence fabrication quality was essential to achieve a reliable and operational electronic board.
| Objective | Description |
|---|---|
| Electronic Design | Create the schematic and PCB layout in KiCad. |
| PCB Fabrication | Fabricate the PCB using a fiber laser engraving process. |
| Assembly | Solder and assemble the electronic components. |
| Programming | Program the XIAO ESP32-C3 using Arduino IDE. |
| Validation | Verify correct operation of the LED roulette sequence. |
2. Components Used
The electronic system was designed around the Seeed Studio XIAO ESP32-C3, a compact microcontroller board with integrated WiFi and BLE connectivity. This board was selected because of its small size, processing capabilities, and sufficient GPIO pins for controlling multiple LEDs independently.
The circuit also included seven LEDs and seven 220 Ω resistors. Each resistor was connected in series with an LED to limit electrical current and protect both the LEDs and the microcontroller pins from excessive power consumption.
Additional materials such as a copper-clad PCB, solder wire, and header pins were used during the fabrication and assembly stages of the assignment.
| Component | Quantity | Function |
|---|---|---|
| Seeed Studio XIAO ESP32-C3 | 1 | Main controller of the LED roulette system. |
| LEDs | 7 | Visual outputs used to create the roulette animation. |
| 220 Ω Resistors | 7 | Current-limiting resistors connected in series with each LED. |
| Copper PCB Board | 1 | Base material used for PCB fabrication. |
| Header Pins | As needed | Used to mount and connect the XIAO ESP32-C3. |
3. PCB Design in KiCad
The PCB design process started in KiCad, an open-source electronic design software widely used for schematic creation and PCB layout development. During this stage, the complete electronic circuit was organized digitally before fabrication.
Each GPIO pin of the XIAO ESP32-C3 was assigned to one LED through a current-limiting resistor. The schematic allowed verification of all electrical connections and ensured that the board would operate correctly before continuing with the manufacturing process.
Schematic Design Process
- Create a new KiCad project.
- Add the XIAO ESP32-C3 symbol.
- Add seven LEDs and seven 220 Ω resistors.
- Connect each LED-resistor pair to a GPIO pin.
- Connect all LED cathodes to GND.
- Run the Electrical Rules Check.
- Correct warnings before moving to PCB layout.
KiCad schematic of the LED roulette circuit.
4. PCB Layout Design
After completing the schematic, the project was transferred to the PCB editor in KiCad to begin the physical layout design. This stage involved organizing the position of all electronic components and routing the copper traces that electrically connect the circuit.
The LEDs were arranged in a roulette-style distribution to create a dynamic visual effect during operation. The XIAO ESP32-C3 was positioned to allow easy USB access for programming and testing.
5. PCB Fabrication with Fiber Laser
Once the PCB design was completed, the fabrication process was performed using a 90 W fiber laser engraver. The laser engraving method allowed direct copper removal on the PCB surface with high precision.
During this process, parameters such as power, speed, frequency, and focus were adjusted carefully to achieve clean traces without damaging the board.
| Parameter | Description |
|---|---|
| Power | Controls the amount of energy applied to the copper surface. |
| Speed | Defines how fast the laser moves over the material. |
| Frequency | Controls the pulse behavior of the fiber laser. |
| Passes | Defines the number of engraving repetitions applied to the board. |
6. Drilling and Cleaning
After the engraving process was completed, the PCB required drilling operations to prepare the holes for electronic components and header connections.
Once drilling was completed, the PCB was cleaned to remove copper particles, dust, and fabrication residues that could generate short circuits.
7. Soldering Process
The soldering stage consisted of assembling all electronic components onto the fabricated PCB. Manual soldering was used to connect the resistors, LEDs, header pins, and the XIAO ESP32-C3 to the board.
Special attention was given to LED polarity, solder quality, and avoiding solder bridges between adjacent pads.
8. Programming the LED Roulette
After completing the electronic assembly, the XIAO ESP32-C3 was programmed using Arduino IDE. The program generates a sequential LED animation capable of simulating the visual effect of a roulette.
int ledPins[] = {2, 3, 4, 5, 6, 7, 8};
int numberOfLeds = 7;
void setup() {
for (int i = 0; i < numberOfLeds; i++) {
pinMode(ledPins[i], OUTPUT);
digitalWrite(ledPins[i], LOW);
}
}
void loop() {
for (int i = 0; i < numberOfLeds; i++) {
digitalWrite(ledPins[i], HIGH);
delay(120);
digitalWrite(ledPins[i], LOW);
}
}9. Testing and Validation
Once the code was uploaded successfully, the PCB underwent a functional validation process. The LEDs responded correctly according to the programmed sequence, confirming successful fabrication and assembly.
10. Problems and Solutions
During the development process, different technical challenges appeared during fabrication, soldering, and programming. Solving these issues was an important part of the learning experience.
| Problem | Solution |
|---|---|
| Some LEDs did not turn on. | Verify polarity and solder joints. |
| Short circuit between traces. | Clean PCB and inspect solder bridges. |
| Laser engraving incomplete. | Adjust laser power and focus. |
| Board not detected. | Check USB cable and Arduino IDE configuration. |
11. Download Files
The following files correspond to the design and fabrication resources developed during this assignment.
12. Final Conclusion
This assignment allowed me to understand the complete workflow of electronics production, from digital design to fabrication and validation of a functional PCB. Through the development of the LED roulette project, I learned how to create electronic schematics and PCB layouts in KiCad, fabricate a board using a fiber laser engraving process, perform drilling and soldering operations, and finally program and validate the XIAO ESP32-C3.
The final result was a fully functional LED roulette PCB capable of generating a sequential animation effect. This assignment strengthened my understanding of digital fabrication workflows and electronics production processes within Fab Academy.