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8. Electronics production

Global Class

The global lecture focuses on fabricating and assembling a PCB, which becomes the foundation for all subsequent electronics work including input devices, output devices, and networking.

A key message is that future assignments depend on having a working board, not just a designed one.

PCB Fabrication Methods

Several fabrication approaches were presented:

  • dead-bug wiring (manual wiring, not recommended)
  • chemical etching (common but hazardous)
  • CNC machining (Fab Lab standard workflow)
  • laser-based methods
  • vinyl cutting

Etching allows fine resolution but introduces environmental and safety concerns.

Machining is preferred in Fab Labs because it is:

  • fast
  • clean
  • suitable for prototyping

Global

PCB Production Workflow

Typical steps:

  1. export design from EDA software
  2. generate toolpaths
  3. mill traces
  4. cut board outline
  5. clean and inspect

The lecture highlighted that PCB production is a deterministic process:

  • correct setup → consistent results
  • errors → usually due to tool, material, or configuration

Assembly and Debugging

Soldering is not a secondary step but a core skill.

Important techniques:

  • clean solder joints
  • desoldering braid
  • hot air rework
  • fixing errors with jumper wires

Debugging is expected and part of the normal workflow.

Key Insight

PCB production can be summarized as:

design → fabrication → assembly → debugging → validation

A board is only complete when it runs code and behaves as intended.

Local Class

Remote Participation

Due to absence from the physical session, this week was documented through:

  • review of classmates’ documentation
  • observation of shared lab workflows
  • comparison across Fab Academy repositories

Observed PCB Workflow

A consistent production process was identified:

  • export design from KiCad
  • generate toolpaths in Mods
  • mill traces and outline
  • clean, solder, and assemble
  • test and debug

Key Observations

  • correct milling depth is critical for trace isolation
  • flat board setup strongly affects results
  • soldering quality directly impacts functionality
  • debugging is a normal and essential step

Common issues:

  • broken or uncut traces
  • solder bridges
  • unstable programming connections

Key Insight

A PCB is only complete when it is:

  • powered correctly
  • programmable
  • functionally verified

Weekly Assignment

Electronics Production

This week focuses on transforming a digital PCB design into a physical and functional board.

The workflow includes:

  • toolpath generation
  • PCB milling
  • component assembly (soldering)
  • debugging and programming

The goal is not only to fabricate a board, but to produce a working embedded system.

Group Assignment

The group assignment focused on understanding and documenting the PCB production process available in the lab.

PCB Production Process

The in-house workflow consists of:

  • exporting traces and outline from KiCad
  • generating toolpaths using Mods
  • milling traces using a CNC machine
  • milling the board outline
  • cleaning and inspecting the PCB

Milling Parameters

Key parameters affecting fabrication:

  • tool diameter (1/64” for traces, 1/32” for outline)
  • cut depth
  • feed rate
  • spindle speed

Proper calibration is essential to ensure:

  • trace isolation
  • consistent depth
  • clean edges

Boardhouse Workflow

The process for sending a PCB to a boardhouse includes:

  • exporting Gerber files
  • verifying layers and drill files
  • uploading to manufacturer platform
  • selecting material and thickness
  • confirming order

Although not executed, the workflow was documented up to submission.

Individual Assignment

Goal

Fabricate and test a microcontroller development board designed in the previous week.

Toolpath Generation

Toolpaths were generated using Mods:

  • imported PNG from KiCad
  • selected appropriate tool diameter
  • defined cut depth and offsets
  • generated milling paths for traces and outline

Key observation:

incorrect parameters directly result in failed boards.

PCB Milling

The board was milled using the lab CNC machine.

Process:

  • fix copper board to bed
  • set origin (X, Y, Z)
  • mill traces
  • change tool
  • mill outline

Critical factors:

  • board flatness
  • correct Z calibration
  • tool condition

Assembly (Soldering)

After milling, components were soldered manually.

Process:

  • solder small components first
  • place microcontroller carefully
  • solder headers and connectors

Tools used:

  • soldering iron
  • flux
  • tweezers

Debugging

Testing followed a structured approach:

  • check for shorts (VCC ↔ GND)
  • verify voltage levels (5V → 3.3V)
  • inspect solder joints
  • confirm continuity

Common issues:

  • solder bridges
  • broken traces
  • unstable connections

Programming

The board was programmed through the SWD interface.

Validation:

  • upload simple program (LED blink)
  • confirm MCU execution

A functional board is defined by:

successful programming and execution of code

Result

The fabricated board demonstrated:

  • correct power regulation
  • successful programming
  • basic input/output functionality

This validates the full workflow:

design → fabrication → assembly → execution

Reflection

This week highlighted that PCB production is not just fabrication, but a complete system process.

Key lessons:

  • simple designs are easier to fabricate and debug
  • milling accuracy directly affects success
  • debugging is an expected part of the workflow

Relevance to ASFALT

This week establishes the foundation for the ASFALT electronics system:

  • validates the controller board fabrication process
  • confirms feasibility of custom electronics
  • defines constraints for future iterations

The priority moving forward is:

design for manufacturability and reliability, not complexity

Use of AI Tools

Prompts

Files

  • KiCad design files
  • toolpath settings
  • source code