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Electronics Production

For this week’s assignment, I had to design and fabricate my own PCB. I decided to create a breakout board for the Xiao RP2040, essentially an extension board that provides access to almost every type of pin and its function. The process involved multiple steps, from designing the schematic to milling the PCB on a Roland SRM-20. Below is a detailed breakdown of my workflow.

Group Assignment

Check it out on my friend Mihir's page

Cleaning Up the Schematic

Although I had already created a schematic in Week 6 (Electronic Design), it was quite messy and not very intuitive. So the first thing I did this week was to:

  • Redesign the schematic from scratch in EasyEDA

  • Label all connections clearly

  • Organize the layout for better readability and troubleshooting

  • Avoid overlapping traces and reduce unnecessary vias

This clean schematic helped immensely in the routing stage later.

week 6 daigram Image

Updated daigram Image

Component Placement: I carefully placed all the components, ensuring proper spacing and logical positioning for easy connections. Image

Schematic to PCB Layout

Once the schematic was finalized, I moved to EasyEDA to create the PCB layout: Image

Board Shape: I designed the PCB in the shape of a rocket .

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Ensured all component footprints were correct and aligned properly.

Design Rules: I set the track width and clearance rules to ensure proper routing and avoid potential short circuits. - Track width: 0.500 mm

  • Clearance: 0.800 mm

  • Via size: Adjusted based on drill bit availability

  • Board outline: Set using the Mechanical Layer in EasyEDA

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Layer Assignments: I set up the board outline layer for cutting and ensured all connections were on the top layer for engraving.

Mounting Holes: I added mounting holes to the design for secure installation.

Auto-Routing & Manual Edits: Since my improved schematic had fewer connection errors, I used autoroute to generate the traces efficiently. After auto-routing, I manually optimized a few connections to ensure a clean and functional layout.

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Mounting Holes: I added mounting holes to the design for secure installation.

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SSS Initials: I also put my symbol of triple s "SSS" in a cool font on my board.

Once satisfied, I previewed the PCB in 3D mode, and it looked great!

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Generating Gerber Files & Preparing for Milling After finalizing the design, I exported the Gerber files needed for PCB milling. Then, I moved on to CopperCAM to prepare the machining layers:

I exported the Gerber files for the following layers:

Top Layer (GTL)– For engraving circuit traces

Drill File (TXT/DRL) – For the through-hole components

Board Outline (GML) – For cutting out the rocket shape and mounting holes Image

Preparing in CopperCAM

With the Gerber files ready, I imported them into CopperCAM to generate toolpaths for the Roland SRM-20 CNC machine.

Layer Setup in CopperCAM:

  • Engraving Layer (Top Layer) – Converted to a toolpath using a 0.2 mm V-bit

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  • Drilling Layer – Converted using a 0.8 mm flat-end bit

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  • Contour Layer (Board Outline) – Set up for cutting the rocket shape and mounting holes

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  • Tool Library-

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Settings:

  • Engraving depth: 0.1–0.15 mm

  • Drilling depth: 1.6 mm

  • Cutout depth (Contour): Full thickness of copper board (1.6 mm)

  • Step down: 0.6 mm per pass (for safe cutting)

  • Speed: Adjusted based on bit size and material

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PCB Milling – First Attempt

I used the Roland SRM-20 CNC machine for PCB milling.

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Tools used:

  • 0.2mm V-bit (Conical) for engraving

  • 0.8mm Flat End Mill for drilling and cutting

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First Attempt – What Went Wrong?

  • I engraved the board successfully using the 0.2mm bit.

  • Then, while drilling holes, I realized something was off — the holes were misaligned!

  • This happened because I accidentally shifted the origin point after the engraving.

  • The drill bit started drilling slightly offset, which would have ruined the whole board.

  • Lesson learned: Always double-check and re-zero the XY origin after changing the tool!

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Successful Milling – Second Attempt

For the second attempt, I carefully followed these steps:

  1. Fixed Copper Plate to the sacrificial layer with double-sided tape

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  1. Set XY origin precisely using the V-bit

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  1. Engraved circuit traces using the 0.2mm bit

  2. Changed to 0.8mm bit, and this time,Re-set the XY origin correctly ,Drilled all pin holes successfully

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  1. Ran the contour cut, which, Cut out the rocket shape perfectly, Also created the mounting holes

Final Board Outcome:

  • Clean engravings

  • Accurately drilled pin holes

  • Neatly cut rocket-shaped board

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Post-Milling: Soldering & Assembly

After successfully cutting the PCB, I moved on to the assembly and soldering phase:

  1. Soldered the RP2040 chip carefully using solder paste and a heat gun.

  2. Added male header pins for easier prototyping and module testing.

  3. Soldered a SMD LED and a 1k resistor to the board — using a magnifying glass to ensure correct orientation of the LED (anode and cathode).

  4. Checked all components visually and with a multimeter to confirm continuity.

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Using the heat gun for reflow soldering gave a clean, professional finish to the SMD components.

HERO SHOT Image

Files

PCB DESIGN Gerber File