Electronics Production

For this week I fabricated the same PCB designed during Week 6. The goal was to move from the electronic schematic and PCB layout into a real, manufacturable board. Instead of sending the design to an external PCB manufacturer, I used in-house digital fabrication to mill the traces directly on a copper board.

The workflow combined several tools: the board design from Week 6, SVG preparation in Inkscape, toolpath generation with mods, and physical machining in the Roland SRM-20. Mods provides a prepared workflow for Roland SRM-20 PCB milling and can take SVG input to generate the machine file. :contentReference[oaicite:1]{index=1}

This week was important because it connected design decisions from the previous week with the physical limitations of PCB production: trace width, isolation, cut depth, and the real precision of the machine.

The board milled in this assignment is the same custom PCB developed in Week 6. That means the fabrication process was not isolated from design: it was a continuation of the previous workflow. By manufacturing the same board, I could validate whether the electronic design decisions were compatible with subtractive PCB production.

This is especially valuable because PCB milling imposes practical constraints. A board may look correct in the CAD environment, but during fabrication issues such as traces that are too close, pads that are too small, or footprints that are difficult to solder may appear. Milling the Week 6 PCB allowed me to verify the board as a real physical object.

Before generating the machining file, I prepared the board artwork as an SVG in Inkscape. This step was important because the milling workflow in mods can start from image/vector input, and SVG is a convenient format to preserve the outlines of the traces and the board geometry. Mods’ SRM-20 PCB workflow explicitly supports loading PNG or SVG input. :contentReference[oaicite:2]{index=2}

In Inkscape, the main objective was to ensure that the exported geometry was clean and ready for toolpath generation. This included checking that:

• the traces were clearly defined,
• the board outline was separated from the trace geometry,
• the exported file preserved the correct scale,
• and unnecessary graphic elements were removed.

Preparing the board in SVG format also made it easier to visually verify the final milling geometry before sending it to mods.

After preparing the SVG, I used mods to generate the toolpath for the Roland SRM-20. Mods is a browser-based fabrication workflow environment, and it includes a specific program for Roland SRM-20 mill 2D PCB. The general workflow is to open the SRM-20 PCB program, load the board file, define the milling parameters, and export the machine file. :contentReference[oaicite:3]{index=3}

In this step I configured the file for PCB milling by selecting the corresponding process for traces and, if needed, a second process for the board outline. This separation is important because the trace isolation and the cutout usually require different cutting conditions and often different tools. Fab Academy’s SRM-20 documentation also describes separating traces from outcut/hole operations in the workflow. :contentReference[oaicite:4]{index=4}

The main purpose of mods in my workflow was:

• to convert the SVG geometry into machining paths,
• to define how much copper would be removed around the traces,
• to control depth, offsets, and milling strategy,
• and to generate the final file that the SRM-20 can execute.

The PCB was fabricated using the Roland SRM-20, a desktop milling machine commonly used for PCB production in Fab Labs. It is a 3-axis machine designed for small-scale precision machining, and it is well suited for engraving traces and cutting board outlines. Roland describes the SRM-20 as a desktop mill for precise contouring and small-format machining. :contentReference[oaicite:5]{index=5}

The machining workflow consisted of:

1. Fixing the copper board securely on the sacrificial bed.
2. Installing the milling tool.
3. Setting the X, Y, and Z origin carefully.
4. Sending the traces job first.
5. Changing to the outline operation after the traces were finished.

Setting the Z origin was one of the most important steps. Since PCB milling removes a very small amount of copper, even a small error in Z height can result in traces that are not isolated correctly or cuts that are too deep.

The complete fabrication process can be summarized as:

What I found most valuable in this workflow was the direct relationship between digital geometry and fabrication result. Any design decision became immediately visible in the milled board, which makes electronics production a very instructive fabrication process.