Electronics Production¶
Group Assignment¶
This week, I worked with my team on PCB production using the Roland SRM-20. We tested a V-bit and a 1/64” endmill. Although the V-bit should have been finer, the 1/64” gave better precision, so we used it for the final board.
I helped set up the machine, generated the G-code, and we successfully milled a test PCB. We also sent Mkhitar’s design to JLCPCB using Gerber files from KiCad. I learned that ordering PCBs makes more sense for larger batches, as shipping is often more expensive than the board itself. Combining orders helps reduce the cost.
Overall, I gained hands-on experience with both in-house and outsourced PCB production.
You can check Whole Group Assignment here
Individual Assignment¶
After designing my circuit, details about which can be found under the Electronics Design week, it’s time to actually bring the PCB to life.
Exporting from KiCad¶
To export files from KiCad I selected Plot option from File menu
Selected SVG as plot format
And also activated Negative plot
For Edge Cuts layer (outline) i disabled negative plot option
CNC¶
Then i went to ShopBot CNC machine, to cut my PCB outline. But before cuting, I painted it with black spray paint (It is much better to cut PCB then to paint, BTW)
Here is it, you can see, that mill removed some paint from edges
CorelDraw and Laser¶
Then I imported ploted files to CorelDraw
made outline of PCB (The Black zone is SVG file format mistake)
Filled it with black paint
And after selecting PCB i moved it on black filled outline.
As you can see it went to back part of black rectangle
So I went to Object menu -> Order -> and selected To Front of Page option
Here it is
Then i moved my PCB design out of printing zone and let only outline in it (concider that line width is set as hairline)
Then in printing menu I selected Vector option and set cardboard cuting parameters
I cuted outline from cardboard
And puted PCB on that place
Then in CorelDraw i brought back PCB on outline
And in printing menu selected Raster option and set Raster parameters
You can see how laser is removing paint from PCB
I did it twice, to clear all paint from non copper zones
Chemistry¶
I will use FeCl3 to clean copper from non painted parts
I added some amount of FeCl3 to warm water
and dissolved it
Then i put PCB into that solution and started to clean copper with brush
I was making rotational movements for about 5 mins
I was checking PCB condition every 2 mins, You can see that there are parts, where copper is already cleaned
One more check
Here it is
Final cleaning and soldering¶
Then i put PCB back to Laser cutter, to clean soldering zones
I drew all of them
and filled that zones with red colour
Then I deleted PCB file and let on Cleaning zones, that I changed from red to black
Here is result
Then I started to solder all parts
Here it is
Next board¶
After I tested this PCB I am going to make new one , which has Raspberry Pi Pico 2W board on it. Also PCB must include “built in” Amplifying circuit and OLED to show which string and how is tuned.
My schematics have 4 parts. Raspberry Pi Pico 2, Amplifying Circuit, OLED connection part, and Power circuit, which is made for powering Pico with 5V, while battery is 9V (I am using simple 5V linear voltage regulator)
I made PCB Design
And made PCB
After final soldering it looks like this
So I wrote program in Thonny (The Programming part is described in my Input Devices week)
And seems like board is working
Safety¶
I used ferric chloride (FeCl₃) to etch my PCB. I knew it was corrosive, so I wore gloves, goggles, and a lab coat to protect myself. I made sure to work in a well-ventilated area to avoid breathing in any fumes.
FeCl₃ can cause serious burns on skin and eyes, and it stains everything it touches. I was careful to avoid spills and cleaned up right away if anything happened.
I also considered the environmental impact. I didn’t pour the used solution down the drain, since it contains copper and other harmful substances. That could damage water sources or soil.
Instead, I neutralized the solution by slowly adding baking soda until it stopped fizzing. Then I let the copper precipitate out and filtered the sludge. I’m storing it safely to take to a hazardous waste center.
Overall, I took all the proper safety and disposal steps to protect myself and the environment.
Programming the Board¶
After the board was ready I went to the next stage of the circuit implementation - programming, details of which can be found under the Final Week documentation.
Conclusion¶
It is very important to know different methods of solving same problem. There are PCBs that are easy to make with CNC and some are better to make with this method.
I learned this method from very good friend of mine, FabAcademy graduate Miqayel Aramyan