Nicole Friederichs – 8. Electronics production

Toolpath Preparation

Preparing Digital Files

The first part of this week was preparing the digital files so the milling machine could understand my PCB. This meant exporting the board correctly from KiCad and then transforming those files into an RML toolpath using Mods.

STEPS FOR THE TOOLPATH:

1. Exporting from KiCad

I exported my PCB from KiCad. Before exporting, I checked in the design rules that all my traces were connected correctly.

1. Exporting from KiCad

In the Plot window, I selected Gerber format and selected only the Edge.Cuts and F.Cu layers since my board had no holes.

1. Exporting from KiCad

Make sure you have these options selected and click on plot.

2. Converting to PNG

KiCad automatically saved one Gerber file for each selected layer. After that, open the Gerber converter and transform the Gerber files into PNG images, which are needed to import into Mods.

3. Configuring Mods

I opened Mods Project. Select the Roland SRM-20 (Because that is the one we have in our Fab Lab, in yours it might be another one.)

3. Configuring Mods

Import the png (gerber) files (You can also import SVG files). You will have to make the proces for each file (traces and cutouts)

3. Configuring Mods

First we are going to do the traces, so choose the tool you will be using. I selected the 60 #501 V-bit for the traces and the 1/16 for the cutout.

3. Configuring Mods

Round the tool diameter to 0.4 (For the trace) and 1.4 (for the cutout). You can also change the offset number, since its my first time soldering I chose an offset of 4.

3. Configuring Mods

Set the speed to 4 mm/s (for the trace and 2 mm/s for the cutout) and put all of the origin axis in 0.

3. Configuring Mods

Turn on the file saving here:

3. Configuring Mods

Click on calculate and your file will be automatically saved. A 3D viewer of how your cut is going to look will also open in another tab.

Final Result:

Milling Process

Working with the Mini Mill

Once the digital files were ready, it was time to move to the mini mill. This was the most challenging part of the week because even a very small calibration mistake could ruin the entire PCB.

STEPS TO MILL THE PCB:

1. Machine Setup

First I installed the VPanel for SRM-20 to control the machine. Then, I fixed the copper board to the MDF pieces provided by our instructor using double-sided tape.

2. Placing the Board

I placed the table in the table machine, inserted the milling bit and tightened it.

3. Connecting

Turn on the machine and connect your computer to de machine to be able to open the program.

4. X and Y Calibration

I set the X and Y origins after I placed them where i wanted to start the traces.

5. Z Calibration

Then I did the z calibration, was the hardest part: I had to lower the bit little by little using trial and error until it barely touched the copper surface. Before calibrating it, DON`T FORGET to rotate the milling cutter, otherwise it will dull.

6. Tracing

Start the process by clicking on the cut window, a tab will appear where you should add the trace file and clicking on Cutput. During my first attempts, if the engraving was too shallow, I lowered the bit a little more and tried again.

7. Outline Cut

After the traces finished cleanly, I prepared the outline cut, it is the same process as tracing but the calibration doesn’t matter as much. Just change the tool and repeat the same calibration and document adding process.

Soldering and Assembly

Assembling the Components

After finally getting a clean PCB, the next step was assembling all the electronic components by soldering them carefully into place.

STEPS TO SOLDER:

1. Preparation and Testing

Before soldering, it is very important to check continuity with a multimeter to verify that the traces are isolated correctly.

2. Soldering Order

I started soldering and used flux to help the solder flow better. I started with the push button, then the male pin headers. After that, I soldered the XIAO RP2350 board. Finally, I soldered the remaining resistors, capacitors, and Neopixels.

3. Final Checks

After soldering, I checked carefully that no solder bridges were created and did another continuity test with the multimeter to confirm everything was connected properly.

Programming

Testing the Electronics

Once the board was assembled, the last technical step was programming it to verify that the electronics were actually working.

STEPS TO PROGRAM:

1. Setup Arduino IDE

My board uses a XIAO RP2350 as the microcontroller. I programmed it using Arduino IDE and made sure the Adafruit Neopixel library was installed.

2. Connection Issues

At the beginning, my computer did not detect the port correctly. I had to troubleshoot the connection until the board was successfully recognized by the software.

3. Uploading Code

Once the board was recognized, I uploaded a simple code to turn on the Neopixels. The code uploaded successfully and the LEDs turned on correctly.

Final Result

After several failed exports, calibration problems, and three milling attempts, I finally obtained a fully working custom development board.

Final Reflection

The PCB works as a custom programmable Arduino-like board that connects through USB and can be programmed normally. Seeing the Neopixels finally turn on after so many fabrication issues made the whole process worth it.

MISTAKES DURING THIS WEEK:

My first Gerber export was wrong.
The Gerber converter merged traces and cuts incorrectly.
Calibration on the mini mill required multiple trial-and-error attempts.
The first milled traces looked rough.
I had to fabricate three PCBs before getting the final working one.

Fails:

Final Result:

8. ElectronicsProduction

Tasks:

Toolpath Preparation

Preparing Digital Files

STEPS FOR THE TOOLPATH:

1. Exporting from KiCad

1. Exporting from KiCad

1. Exporting from KiCad

2. Converting to PNG

3. Configuring Mods

3. Configuring Mods

3. Configuring Mods

3. Configuring Mods

3. Configuring Mods

3. Configuring Mods

3. Configuring Mods

Final Result:

Milling Process

Working with the Mini Mill

STEPS TO MILL THE PCB:

1. Machine Setup

2. Placing the Board

3. Connecting

4. X and Y Calibration

5. Z Calibration

6. Tracing

7. Outline Cut

Soldering and Assembly

Assembling the Components

STEPS TO SOLDER:

1. Preparation and Testing

2. Soldering Order

3. Final Checks

Programming

Testing the Electronics

STEPS TO PROGRAM:

1. Setup Arduino IDE

2. Connection Issues

3. Uploading Code

Final Result

Final Reflection

MISTAKES DURING THIS WEEK:

Fails:

Final Result:

8. Electronics
Production