4. Electronics Production
First of all, in our group webpage, we explain about PCB milling. Where we cover topics such as what PCB milling is, materials, safety guidelines, tooling, some aspects of the process, and more! Please make sure to verify your model and its characteristics before starting.
Our FabLab uses this machine: ROLAND SMR-20
![...](Images week 4/roland.jpg)
PCB milling is used to make circuit boards. A rotary cutter carves away the copper path, creating circuit traces. So... where do we start?
First of all, we need two images in PNG format: traces and outline cut (these are in files section).
Toolpath creation
Access in MODs page
![...](Images week 4/Whitemod.jpg)
Then right-click on the screen and following the next route.
Programs -> open program -> in Roland section/SRM-20 mill choose mill 2D PCB
![](Images week 4/programs.jpg)
![](Images week 4/openprogram.jpg)
![](Images week 4/mill2dpcb.jpg)
Looks catastrophic and complicated, but don't worry is easier than you expect.
![...](Images week 4/catastrophic.jpg)
Traces
![](Images week 4/selecttracespng.jpg)
1. Select the traces png file
![](Images week 4/milltraces164.jpg)
2. Click on mill traces 1/64
![](Images week 4/offsetnumber.jpg)
3. Change offset number to 2
![](Images week 4/turn on.jpg)
4. Set x, y and z origins to 0
![](Images week 4/xyz.jpg)
5. and turn on "edit delet"
![](Images week 4/calculatetraces.jpg)
6. Calculate traces
This way you get the rml file
![...](Images week 4/rmltraces.jpg)
outline
![](Images week 4/selectoutline.jpg)
1. Select the outline png file
![](Images week 4/invert.jpg)
2. Click on invert
![](Images week 4/milloutline132.jpg)
3. Select mill outline 1/32 and automatically changes offset number to 1
![](Images week 4/tooldiameter.jpg)
4. Set tool diameter to 0.8 mm
![](Images week 4/xyz.jpg)
5. Keep all configurations unchanged
![](Images week 4/calculateoutline.jpg)
6. Calculate outline
This way you get the rml file
![...](Images week 4/rmloutline.jpg)
IMPORTANT if you don't click on invert outline image, you will get a wrong rml file. Since PCB milling machine will cut the edges of the outline. Like this:
![](Images week 4/badcut.jpg)
Bad outline
![](Images week 4/oops.jpg)
Equal a bad cutting
PCB Milling
I placed double-side tape on my copper plate to stick it onto an MDF board, aiming to avoid cutting into the metal base of the machine in case I went too deep. Later, I secured my board to the machine with screws.
![...](Images week 4/copperplate.jpg)
So, before to cut I place the V-bit tool in the machine for engraving.
![](Images week 4/tooling.jpg)
![](Images week 4/changetool1.jpg)
Steps to prepare mini mill machine (CNC)
![...](Images week 4/vpanel.jpg)
- Download and install the driver and Vpanel software.
- Turn on and connect cables to the computer.
- Set origin in the x and y axis.
- If you lower too quickly on the Z-axis, the tool may break. Therefore, use microns (x1) when you are close to the board. I placed a paper under the tool to ensure it was well-positioned.
- Once the tool is over the board, activate the tool with the spindle option when it reaches 8000 revolutions per minute. Lower it by 1 to 2 microns. At this point, set the origin z-axis.
- Upload (add) your file and start to cut (output).
![...](Images week 4/file.jpg)
After the process, be sure to clean up.
![](Images week 4/machining.jpg)
![](Images week 4/clean1.jpg)
Change the V-bit tool to a two-flute end mill for cutting, and then begin the cutting process.
![](Images week 4/tooling2.jpg)
![](Images week 4/changetool2.jpg)
![](Images week 4/machining2.jpg)
![](Images week 4/clean2.jpg)
Excellent! Now, we have our PCB. I applied some electrical tape behind my chip to safeguard the connections underneath.
![...](Images week 4/nooopss.jpg)
Before soldering, review the schematic file and the circuit diagram.
![](Images week 4/eschematic.jpg)
![](Images week 4/diagram.jpg)
It's time to solder.
![](Images week 4/me.jpg)
![](Images week 4/me2.jpg)
Perfect! I suggest starting by soldering the processor and then the smaller components. For the latter, it's helpful to apply solder to the board first and then only heat it when placing the components.
![...](Images week 4/welding.jpg)
Code and testing
Here is the web tutorial to connect the Seeed Studio XIAO RP2040 to the computer and upload a simple code from Arduino to check whether the board is functioning well.
After all, connect your circuit to the computer and then choose the port in the Arduino software.
![...](Images week 4/port.jpg)
In boards, choose Seeed XIAO RP2040.
![...](Images week 4/selectxiao.jpg)
Then upload the code, which you can find in the file section.
![...](Images week 4/upload.jpg)
Testing
And finally:
![...](Images week 4/final.jpg)
Files
- CutPuebla
- TracesPuebla
- CutPuebla.rml
- TracesPuebla.rml
- Blink code