Week 8 - Electronics Production
Assignments
Group Assignment
- Characterize the design rules for your in-house PCB production process: document feeds, speeds, plunge rate, depth of cut (traces and outline) and tooling.
- Document the workflow for sending a PCB to a boardhouse.
- Document your work on the group page and reflect on your learning on your individual page.
Individual Assignment
- Design, make, and test a microcontroller development board.
Learning Outcomes
- Describe the process of toolpath generation, milling, stuffing, debugging, and programming.
- Demonstrate correct workflows and identify areas for improvement if needed.
My Work
During the Electronics Production week, I learned how to manufacture a printed circuit board (PCB). I designed my board and used an SRM-20 milling machine to cut it from a PSB board. The process included preparing the design files, setting up the machine, and carefully milling the traces and outline. This week helped me understand how digital designs become physical hardware.
PCB Production Process
1. Export Gerber Files
- Go to Fabrication Outputs and select Gerber as the file format.
2. Generate Drill Files
- Select Generate Drill Files.
3. Generate All Files
- Ensure all settings are correct and output is created without errors.
4. Download and Organize Gerber Files
- Download all Gerber files (drill, traces, outline) and prepare them for manufacturing.
Converting Gerber Files
- Use Gerber2PNG to generate images of PCB layers.
- Download three main files: drill, traces, and outline.
- Drill: for holes
- Traces: for electrical paths
- Outline: for board shape
- Carefully check each file before milling.
Preparing NC Files in Mods CE
- Open Mods CE and go to the G-code section.
- Select Mill 2D PCB for milling.
- Prepare each file (traces, drill, outline) separately.
- Set tool settings, speed, and cut depth for each.
- Generate NC files for the SRM-20 machine.
- Check toolpaths visually to avoid mistakes.
SRM-20 Milling Machine
The SRM-20 is a desktop milling machine commonly used for small PCBs. It uses rotary tools to cut traces and drill holes. Proper maintenance and setup are essential for a smooth milling process.
Cutting Tools
- Thin tool: for milling traces
- Larger tool: for drilling holes and cutting board outline
- Correct tool choice ensures precision and prevents damage.
Fixing the PCB
- Secure the PCB material on the machine bed using double-sided tape.
- Ensure it is level and aligned with the machine origin (X, Y, Z).
- A stable PCB prevents errors during milling.
Milling in VPanel
- Load NC files in the sequence: traces → drill → outline.
- Monitor the machine carefully and pause if necessary.
- After milling, the PCB is ready for assembly.
Preparing Components
- Components include:
- ESP-32 chip
- Resistors (5×1002Ω)
- Headers (1×08, 1×03, 1×02)
- 1 LED
- 2 buttons
- Preparing components first saves time during soldering.
Soldering Components
- Solder each component carefully.
- Ensure connections are secure and there are no cold joints.
- Patience and attention to detail are key.
Board Completion
- After soldering, the PCB is fully assembled and visually complete.
- Next step: test electrical connections and functionality.
Mistakes and Issues
- Some mistakes occurred: two capacitors were not connected, and one resistor on the RST line was missing.
- These small errors prevented the board from working correctly.
- Learning from mistakes is important for future improvements.
Conclusion and Future Improvements
- This was my first PCB, and I am still learning.
- Next time, I will carefully fix errors and produce a more reliable board.
- I plan to improve the design iteratively, making each PCB more precise and functional.