Electronics Production¶
Group assignment
- Characterize the design rules for your in-house PCB production process: document feeds, speeds, plunge rate, depth of cut (traces and outline) and tooling.
- Document the workflow for sending a PCB to a boardhouse
- Document your work to the group work page and reflect on your individual page what you learned
Individual assignment
- Make and test a microcontroller development board that you designed
Learning outcomes
- Described the process of tool-path generation, milling, stuffing, de-bugging and programming
- Demonstrate correct workflows and identify areas for improvement if required
Have you answered these questions?
- Linked to the group assignment page
- Documented how you made the toolpath
- Documented how you made (milled, stuffed, soldered) the board
- Documented that your board is functional
- Explained any problems and how you fixed them
- Uploaded your source code
- Included a ‘hero shot’ of your board
Time Management¶
You can access my timetable here.
Group Assignment¶
You can access the link to our group assignment page here.
Monofab SRM-20 Milling Machine
The Monofab SRM-20 Milling Machine is a compact, user-friendly device for precision milling and prototyping applications in various industries.
Here is a picture of the one at the lab.
Machine and Specifications¶
Cuttable Material: Modelling Wax, Chemical Wood, Foam, Acrylic, Poly acetate, ABS, PC board
X, Y, and Z Operation Strokes: 203.2 (X) x 152.4 (Y) x 60.5 (Z) mm
Distance From Collet Tip to Table : Max, 130.75mm (5.15 in)
Loadable Workpiece Weight : 2 kg (4.4 lb)
X-, Y-, and Z-Axis Drive System : Stepping motor
Operating Speed : 6 - 1800mm/min 0., - 70.87inch/min
Software Resolution : 0.01 mm/step (RML-1), 0.001mm/step (NC code), 0.000039 inches/step (RML-1), 0.000039 inches/step (NC code)
Mechanical Resolution : 0.000998594 mm/step, 0.0000393 inches/step
Spindle Motor : DC motor Type 380
Cutting Tool Chuck : Collet method
Included Items : USB cable, AC adapter, Power cable, Cutting tool, Collet, Set screw, Spanners (7,10mm), Hexagonal wrench (size 2,3 mm), Positioning pins, Double-sided tape, Start-up page guidance card
Reflection¶
I was able to learn quite a lot this week. Our group tested PCB fabrication parameters, documented results, and learned about milling and soldering. Understanding PCB milling and soldering helped me design, mill, and solder custom circuits for my final project.
Individual Assignment¶
This week’s assignment required us to make and test a microcontroller development board that I had designed during the earlier weeks, which is my first demo of my final project board. I had used a Xiao microcontroller.
Generating toolpath in Mods CE¶
After designing the PCB of your schematic design, Mods CE is used to generate its toolpath. To get a proper tutorial on this, visit my week 6 documentation. Although it was not required for week 6’s assignment, we had already generated the toolpath of the PCB design we made which made this week’s work much easier.
Here is the result of the final toolpath generated. An rml file should also be downloaded of both the traces and the edge cuts. This is the toolpath of the traces of my board.
Milling¶
After you are done creating the rml files for all your designs, you can start milling. The milling machine we have at the Fab Lab is the monoFab SRM-20. To learn more about it, you can go through its manual.
The software we are going to be using is the VPanel for SRM 20. This is what its user interface is like.
Don’t forget to set your x, y, and z origins! It is the reference point the machine uses to begin milling.
Setting the X and Y origin
Open the software and make sure the machine is connected and turned on. You can use the arrows to move the tool head in the machine and position it exactly where you want your design to start. Click the [Set Origin Point] button and select [X/Y] to save this position as the new X and Y origin.
Setting the Z origin
Use the down arrow button to carefully move the tool downwards, right a bit above the surface. Then you can manually use an Allen key to bring the end mill to touch the surface. Once the Z-height is set, click [Set Origin Point] and select [Z] to save the Z origin.
After you are done, tap on the ‘cut’ button, delate the previous files, and select the file you want to mill. Press on output to start.
Types of end mills
End mills are the tools used by the machine to actually trace and cut your board. There are 2 types of end mills, the 1/32 and the 1/64.
The 1/64 end mill is used first to trace your board. This end mill is very delicate so when configuring your z-axis, you have to be very careful not to break it.
The 1/32 end mill is used to cut the board after you are done tracing it. An Allen key is used to switch between the end mills.
Milling is done!
Soldering¶
After you are done milling, you should start soldering. Soldering refers to the process of joining your components by melting a filler metal called solder. It is able to create a strong electrical and mechanical connection without melting the actual components.
Practising
Before I started to actually solder my board, I practised a bit with a few boards in our lab that did not work anymore.
Soldering is honestly really really fun!! I also made a lot of errors in the beginning and my hands were shaking a lot(which is why I might have also brunt my hand in the first place😔). I dont know how I did it but I also made the wire stuck with my hardened solder which is really weird and this is how it was sticking out of the board.
The list of components I require for the board:
This is my board after soldering.
Programming¶
I am using Arduino IDE for programming. If you haven’t already downloaded it, use this link.
Testing¶
To test if my board was actually working or not, I am planning to do the blink test. Follow along with me here!
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After downloading the application, go to tools>board and choose the board you are using. If you can’t find it, you might have to download it from ‘boards manager’. The board I am using is the Xiao_ESP32C3.
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Now, open the blink code.
This is the code:
```
void setup() {
// initialize digital pin LED_BUILTIN as an output.
pinMode(D0, OUTPUT);
}
// the loop function runs over and over again forever
void loop() {
digitalWrite(D0, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(D0, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
}
```
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Make sure you have assembled your required components and connected the USB to your laptop.
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Select your USB port. This allows your laptop to upload code and commnunicate with the MCU.
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Run your code. Here are the results:
Now that I have confirmed that my board works, I will try to implement an electromagnet with a switch which can turn the magnet on and off. This will help me better understand how these components are supposed to work in my final project.
I asked ChatGPT to generate the code for me and this is the prompt I am using after attaching the blink code:
This is the code I am using for my microcontroller right now which basically connects to a relay module which connect to an electromagnet. Every one second the electromagnet loses its power and gains its power and vice versa(cause of the blink code). now in another pinout, i want to add a switch which can control when the electromagnet powers up instead of it being powered up with a delay of 1 second. write a code to implement that feature.
After a bit of debugging, this is my final code:
const int relayPin = D0; // Relay module connected to D0 (controls electromagnet)
const int switchPin = D1; // Switch connected to D1
void setup() {
pinMode(relayPin, OUTPUT);
pinMode(switchPin, INPUT_PULLUP); // Enable internal pull-up resistor
}
void loop() {
int switchState = digitalRead(switchPin);
if (switchState == LOW) { // Switch ON (connected to GND)
digitalWrite(relayPin, HIGH); // Turn ON the electromagnet
} else { // Switch OFF (floating HIGH)
digitalWrite(relayPin, LOW); // Turn OFF the electromagnet
}
}
Results!!
Reflection¶
I personally enjoyed soldering the most. The challenge of getting a perfect solder joint without messing things up kept me really engaged. Watching the metal melt into the components was also weirdly satisfying. I am glad that I at least tested my board and worked with a component of my final project, the electromagnet. It made me understand how they work together better.
Original Design Files¶
Thank you!
The template for this website was provided by Mr. Anith Ghalley and used with his permission