Week 08 — Electronics Production
Group Assignment
The objective of this week's group assignment was to explore and characterize the process of fabricating printed circuit boards (PCBs) using the equipment available in the Electronic Laboratory of the Pontificia Universidad Católica del Perú (PUCP). This activity allowed us to understand the complete workflow required to produce a PCB, from the digital design to the physical manufacturing of the circuit.
During this session we reviewed the different stages required to produce an electronic board using CNC machining, as well as the parameters and tools that influence the quality of the final result.
PCB Fabrication Workflow
The PCB production process in the laboratory follows several steps that transform a digital design into a functional electronic circuit.
The main stages of the workflow are:
- Electronic circuit design using an EDA software such as KiCad.
- Exporting the design or generating machining paths.
- Generating the machine code (G-code) that will control the CNC milling machine.
- Milling the traces to remove copper and isolate the electrical connections.
- Drilling the holes required for electronic components.
- Cutting the board to obtain the final shape.
- Cleaning the PCB to remove residues from the machining process.
This workflow allows rapid prototyping of electronic circuits within the digital fabrication laboratory.
Machines Used
Several machines available in the PUCP digital fabrication laboratory were used during this process, each one performing a specific function in the production workflow.
CNC Milling Machine
The circuit traces were produced using a Genmitsu CNC milling machine, which is commonly used for PCB prototyping in fabrication laboratories. This machine removes copper selectively from a copper-clad board in order to isolate the traces of the circuit.
Main characteristics include:
- Numerical control using G-code
- Movement in three axes (X, Y, Z)
- High precision for milling fine traces
- Compatibility with different engraving tools
A V-bit engraving tool was used to mill the copper surface and isolate the circuit traces.
Bench Drill
After the milling process, a bench drill was used to create the holes required for through-hole electronic components. This machine allows precise and controlled drilling, ensuring that the component leads fit correctly into the board while reducing the risk of damaging the PCB.
Manual Shear Cutter
Finally, a manual shear cutter was used to cut the copper board and obtain the final dimensions of the PCB. This tool allows clean and controlled cuts on rigid materials such as copper-clad boards used for electronics production.
Milling Process Characterization
During the group assignment several aspects of the milling process were analyzed, as these parameters directly affect the quality of the PCB.
Cut Depth
The cutting depth determines how much material is removed from the copper layer. If the depth is too small, the traces may not be completely isolated. If it is too deep, the base material of the board may be damaged.
Tool Type
V-bit engraving tools were used because they allow the creation of very fine and precise traces, which are necessary for electronic circuits.
Material Fixation
The copper board must be firmly fixed to the machine bed to avoid vibrations or movement that could affect the precision of the milling process.
Feed Rate
The feed rate of the tool also influences the milling quality. If the speed is too high, the cuts may become inaccurate. If it is too slow, the fabrication time increases significantly.
Safety Considerations
PCB fabrication using CNC milling machines requires following basic safety procedures.
- Wear safety glasses during the machining process.
- Ensure the copper board is properly fixed before starting the machine.
- Verify that the milling tool is correctly installed.
- Keep the working area clean.
- Never leave the machine operating unattended.
Following these precautions helps prevent accidents and ensures proper machine operation.
Group Learning Outcomes
This activity allowed us to understand the complete PCB production workflow within a electronic laboratory. The process integrates electronic design, CNC machining, mechanical finishing, and safety procedures.
Through this exercise we learned how different fabrication parameters influence the final quality of the circuit and how proper preparation of the board and machine setup are essential for successful PCB production.