W8 | Electronics Production

The machine we use for PCB fabrication is the Carvera by Makera— a compact, professional CNC mill designed for precision work. It connects to a laptop via USB and is controlled through the Carvera Controller software, where toolpaths are loaded and the milling process is monitored in real time.

These specifications are important for PCB production because precision is critical — even a small mistake in depth or positioning can damage traces or create short circuits. Two features of the Makera Carvera make the process much more reliable, particularly for first-time PCB fabrication:

Auto probing and leveling

Before milling, the Carvera automatically measures the board surface at multiple points and compensates for any small irregularities. This ensures the bit cuts at the same depth across the entire board, even if the surface is not perfectly flat after sanding.

Automatic Tool Changer

The Carvera switches from the trace bit to the outline bit automatically, without any manual intervention. This reduces the chance of errors when changing tools mid-process.

Tool 4 — For traces
Single Flute Engraving Bit for Metal — 60° × 0.1mm tip, 1/8" shank

This V-shaped bit is used to mill the copper traces. Its very fine tip allows it to cut precise, narrow paths between traces without damaging adjacent copper.

Tool 3 — For outline
TiN Coating Corn Bit — 0.8mm × 5.5mm, 1/8" shank

This cylindrical bit is used to cut the board outline. It is more robust than the engraving bit and can cut through the full thickness of the PCB in multiple passes.

1. Copper PCB blank — the base material where the circuit will be milled
2. MDF board — placed underneath to protect the machine bed and allow the outline cut to go all the way through
3. Screws and metal clamps — to secure the board so it does not move during milling
4. Screwdriver — to tighten the clamps
5. Sandpaper 180 grit — to prepare the copper surface before milling
6. Mini vacuum cleaner — to remove copper dust between operations

Before placing the board in the machine, the copper surface needs to be sanded with 180 grit sandpaper. This step is easy to overlook but very important — the copper surface is rarely perfectly flat. Even small irregularities can cause the engraving bit to cut at different depths across the board, resulting in traces that are too shallow in some areas and too deep in others. Sanding ensures a uniform surface so the bit cuts consistently.

Once sanded, the board is placed on top of the MDF and secured to the machine bed using the metal clamps and screws. It is important to tighten them firmly — any movement during milling will ruin the traces.

2. Load the Traces image

The traces PNG is loaded into the Traces image section. This image tells the machine exactly where to mill the copper to create the circuit traces — ModsProject reads it and translates it into movements the Carvera can execute.

3. Load the Exterior image and configure Tabs

The outline PNG is loaded into the Exterior image section. This is also where the Tabs are configured — small bridges of material that keep the board attached to the copper sheet during the outline cut. Without tabs, the board could shift or fly off the moment it is fully cut through, ruining the result.

📝 The note in ModsProject also reminds which physical tools to load in the Carvera:

• 🖰 Tool 3 → 1/32" (0.8mm) corn bit → outline
• 🖰 Tool 4 → 1/64" (0.4mm) engraving bit → traces

2. Mill the traces

Once calibration is complete, click 🖰 Run and the Carvera starts milling the traces with Tool 4. The machine works through the entire toolpath automatically — no manual intervention is needed while it runs.

3. Vacuum the copper dust

After the traces are milled, copper dust is left on the surface of the board. This must be vacuumed before continuing — copper dust can interfere with the outline cut and is also harmful to inhale.

4. Mill the outline

The outline 📁 .nc file is now loaded into the Carvera Controller. The same calibration process runs automatically before cutting begins. Once ready, click 🖰 Run and the Carvera cuts the board outline with Tool 3 in multiple passes until it goes all the way through.

2. Start a new order and upload the Gerber files

To start a new order, click 🖰 Add Gerber File. JLCPCB accepts Gerber files compressed in a 📁 .zip folder — this is the standard export format from KiCad. Once uploaded, the platform automatically reads the files and generates a preview of your board.

3. Review the board preview and DFM Check

After uploading, JLCPCB shows a preview of your board including a 2D view, 3D view, and individual layer views. It also runs a DFM Check (Design for Manufacturability) — similar to the DRC in KiCad — which verifies that your design meets the minimum manufacturing requirements. This is a useful check before placing the order. In our case the board was detected as a 2-layer board of 44.54 × 51mm.

5. Review the price and save to cart

For this exercise we kept the default settings and selected 24-hour build time for faster fabrication. Adding the boards to the cart shows the full order summary — board specs confirmed as Green, 1.6mm thickness, HASL finish, 5 units.

Testing the fastest available shipping option to Peru via DHL Express, the estimated delivery time is 3 to 6 business days. The order is ready to be placed.

This week I learned that the PCB milling workflow depends a lot on correct preparation before the machine even starts cutting. Going from Gerber files to PNG images, configuring the tools in ModsProject, and generating the G-code made the whole process feel much more practical and connected. The line test was especially useful because it helped us understand the real limits of the machine and tools before milling the final board. It also confirmed that our design was within a safe manufacturing range. I also learned that each tool requires different configurations, and using incorrect parameters can affect the milling result or even damage the bit. Another important step was verifying the traces with a multimeter to check continuity and confirm that there were no unwanted connections between traces.

For the boardhouse workflow, using JLCPCB was straightforward once the Gerber files were ready. One thing I noticed was that the minimum order is 5 boards, and the shipping cost to Peru was much higher than the fabrication cost itself. Because of that, using a boardhouse becomes more practical when you need boards in larger quantities.

3. Select the necessary views

I selected the necessary views for board fabrication.

4. Convert to PNG format

I converted the required layers to PNG format, as Carvera requires this format in ModsProject.

Traces

External Cut

Select the machine

Carvera Mill PCB

Then, I configured the parameters for the Single Flute Engraving Bit - 1/8" 60° × 0.1 mm, located in position 4 of the machine.

After adjusting the settings, I generated the G-code for the traces and saved it in a folder.

I configured the parameters for the Coating Corn Bit - 1/8" 0.8 mm × 5.5 mm, in position 3 of the machine.

Once everything was set, I generated the G-code for the outline cut and saved it in a folder. With both G-code files ready, it was all set to load them into Carvera Controller and start the milling process!

1. Opening Carvera Controller

I opened Carvera Controller, connected to 📁 COM7 (the COM port depends on your laptop/PC), and loaded the toolpath files generated by ModsProject into the machine's local memory.

⚠️ Important — Safety Note: It's important to wear safety glasses while vacuuming, as tiny fiberglass particles from the board could get into the eyes.

The Brain Board was an important first step in understanding the complete PCB milling workflow. Fabricating it helped me become familiar with each stage of the process, identify possible issues early, and gain more confidence before working on the Final Project PCB. After finishing the Brain Board, the workflow felt much clearer and more organized for the next board.

With the experience from the Brain Board fresh in mind, I moved on to fabricating the Final Project PCB. The milling process followed the same workflow — preparing the copper blank, converting the Gerber files to PNG using Gerber2PNG, generating the toolpaths in ModsProject, loading the files into Carvera Controller, and running both the trace and outline cuts.

With the board freshly milled, it was time for soldering. This was my first time working with components this small, so the process required much more precision and patience than the larger components I had soldered before.

Before turning on the soldering iron, I first organized all the parts on the table. In total, the board used 14 SMD components, and laying everything out beforehand helped me clearly identify each part and make sure nothing was missing before starting.

All 14 components on this board are SMD (Surface Mount Device), meaning they sit directly on the copper surface and are soldered in place without passing through the board. This keeps the design compact and clean.

Step 1 — Setting Up the Workstation

Before starting the soldering process, I organized all the necessary tools within reach: the soldering iron, solder wire, flux paste, a brass wire tip cleaner, and a damp sponge. Keeping the workstation clean and organized made the process easier, especially when working with small SMD components that require more precision.

Step 2 — Applying Flux

One thing I learned very quickly is that flux makes the soldering process much easier. Before placing each component, I applied flux paste to the pads to improve solder flow and help the solder bond cleanly to the copper. It also reduced the chances of creating cold joints, which was especially helpful when working with small SMD components.

Step 3 — The Soldering Order

ones firstOne of the most important parts of stuffing a board is deciding the soldering order. I started with the smallest SMD components first and then continued outward from the center of the board. This made the process easier and prevented larger components from blocking access to smaller pads later on.

The PCB includes dedicated pin headers for two main connections: one for the Seeed Studio XIAO ESP32S3 module and another for the external 5V power supply. Keeping these connections separated makes the system easier to power, test, and replace when needed.

For the test, I connected a 16-LED NeoPixel ring to the board using female-to-female Dupont cables for signal, 5V, and GND. The external 5V connection was necessary because the LED ring requires a dedicated 5V supply to operate correctly.

⌨️ The Code

The test program was written in Arduino IDE using the Adafruit NeoPixel library. The code sequentially turns on each LED of the 16-LED NeoPixel ring with white light until the entire ring is illuminated. The animation then repeats continuously in a loop.