Electronics Production

Tasks for this week

Individual assignment:

• make and test a microcontroller development board

group assignment:

• characterize the design rules for your in-house PCB production process

• send a PCB out to a board house

Group Assignment

The Week 4 Group Assignment is to characterize the design rules for the in-house PCB production process and also to send a PCB out to a board house.

The final result of the finished PCB for the line test looks like this. The test demonstrates that we can achieve trace widths as narrow as 0.001 inches (0.0254 mm) using a 0.4 mm (1/64") flat endmill with proper calibration. For comparison, we also conducted a test with a 0.8 mm (1/32") flat endmill. The picture illustrates the difference, we can't get accurate traces with the 0.8 mm flat endmill.

Group Assignment Page Link- Click here

PCB Milling

To produce a PCB, we will utilize the ROLAND MODELA MDX 20 "PCB" milling machine at our fabrication facility. This machine boasts a bed size measuring 220mm (X) x 160mm (Y) and offers a precision of approximately 0.006mm. The Roland Model MDX-20 is specifically engineered as a desktop milling machine, adept at crafting precise models and prototypes from various materials, including plastic, wood, and metal.

Specifications

Tool chuck	6 mm or 1/8 in. tool chuck included
Spindle motor	10W (DC motor)
Software resolution	0.025 mm/step (0.000984 in./step)
Mechanical resolution	0.00625 mm/step (0.000246 in./step)
Revolution speed	6,500 rpm
Feed rate	0.1 to 15 mm/sec. (0.00393 to 9/16 in./sec.)
Acceptable material	Wood, Plaster, Resin (modeling wax, styrenform), Chemical wood
Acceptable tool	Endmill, Drill

For milling PCB we are milling Quentorres. swd+uart adapter+hello board - xiao rp2040 the design is available at fab academy schedule

Then I personalized to my Board using GIMP

I have opened the png File in GIMP and changed the board name

Using text tool i have changed the name

Then I exported to .png format for milling

Fab Mods

We use FAB MODs to control the machine. I already have some experience in using MODs during the third week for vinyl cutting.

1. navigate to the Fab Mods directory in the terminal and execute the "start-servers" file using the following command:

  bash start-servers

right-click on the screen>programs>open program and this page appears, from this choose PCB under MDX mill

I uploaded my file as .png and then chose 1/64" as my milling tool and selected calculate.

Then calculated and click send file

Then for drilling and edge cutting the tool is changed to 1/32"

For Drilling i have imported the drilling files to Fab Modes

For cutting the outer shape, the png file is imported to FAB Modes

Milling Procedure

Selection of tools

For milling the PCB we have to use 0.4 and 0.8 mm bits.

0.4mm bit for tracing the paths and 0.8mm bit for cutting the outer border

Here i used used board of dimetions 47mm x 47mm it is a standard size

• Apply double side tape on the other side of FR1 sheet

• stick the pcb to the bed

Changing the tool

Using an allen key change the tool of 0.4 mm mill bit for tracing the path

Next, position the spindle at the top of the PCB using coordinates of X 50 -Y 50. Then, lower the z height until it nearly touches the board. After that, release the bit and carefully bring it into contact with the board manually.

Then started the milling by sending files via MODS

The next phase entailed drilling the requisite holes and carving out a border for the milled PCB. We obtained the relevant .png files from Fabcloud and imported them onto MODs.

Following this, I switched to a 0.8mm (1/32") bit, ideal for cutting and drilling, and proceeded with the same procedure. Below is the final result.

Selecting the components

At our Fablab, we use inventory.fablabkerala.in to request components available in our inventory. After receiving login credentials, I proceeded to add the required components to the cart based on the provided list and submitted the request. Upon approval by the Admin, I then collected all the necessary components

After approval i have collected all items from our inventory and pasted on my Paper

Soldering

Soldering is a process of joining two metal surfaces together using a filler metal called solder. The soldering process involves heating the surfaces to be joined and melting the solder, which is then allowed to cool and solidify, creating a strong and durable joint.

1. Soldering Station:
   A soldering station is like a control center for soldering. It's a device with a base where you can place your soldering iron when not in use. Some models allow you to control the temperature for precise soldering work.
   

2. Soldering Iron:
   A soldering iron is the tool you use to melt solder and join electronic components together. It's like a pen with a heated metal tip that you can hold and use to make connections.
   

3. Silicone Mat:
   A silicone mat is a heat-resistant pad that protects your work surface from damage when soldering. It's like a cushion that prevents burns and keeps your workspace clean.
   

4. Solder:
   Solder is a metal alloy that melts at a low temperature and is used to make electrical connections. It's like the glue that holds electronic parts together.
   

5. Tweezers:
   Tweezers are small tools with fine tips that help you handle tiny electronic components. They're like tiny fingers that allow you to pick up and place parts precisely.
   

6. Desoldering Pump:
   A desoldering pump is a tool used to remove excess solder from joints. It's like a vacuum cleaner for solder, sucking up molten metal so you can start fresh.
   

7. Desoldering Wick:
   Desoldering wick is a braided copper wire coated with flux. It's like a sponge that soaks up melted solder, helping you clean up messy joints and fix mistakes.
   

Safety Measures While Soldering

• Never touch the tip or element: It gets extremely hot (around 400°C) and can cause severe burns.

• Use safe handling tools: Hold hot wires with tweezers, pliers, or clamps to avoid burns.

• Keep the cleaning sponge wet: This prevents fire hazards and helps clean the tip effectively.

• Use a stand: Always return the iron to its stand when not in use, never leave it on the workbench.

• Inspect cords regularly: Check for damage like fraying or cracks before each use. Replace faulty cords immediately.

• Unplug when not in use: This reduces the risk of electrical accidents.

• Choose a fire-resistant surface: Wood or paper should be avoided. Invest in a heat-resistant soldering mat.

• Maintain a clean and organized workspace: This minimizes clutter and potential fire hazards.

• Ensure proper ventilation: Solder fumes can be irritating and harmful. Use a well-ventilated area (open windows/fans) or a fume extractor.

• Wear appropriate clothing: Long-sleeved shirts, pants, and closed-toe shoes protect you from hot solder splashes and burns.

• Eye protection is essential: Wear safety glasses or goggles to shield your eyes from hot solder splatter and debris.

Soldering

In orfer to solder the components to the Quentorres. swd+uart adapter+hello board - xiao rp2040 i have used the circuit diagram

Soldering surface-mount (SMD) components can pose a challenge as it demands the use of both hands to accurately apply the solder. To tackle this difficulty, I utilized a method where I initially applied solder to one of the pads before positioning the component. This method ensured the accurate alignment and secure attachment of the component to the board.

Final Result

Blinking LED

I downloaded Arduino IDE 2.3.1  from website

I followed to the instructions provided on the website.

I simply needed to add the board by navigating to File > Preferences > Board Manager and pasting the link for the Arduino-Pico package.

https://github.com/earlephilhower/arduino pico/releases/download/global/package_rp2040_index.json

Then, open Tools > Board > Board Manager. Type "pico" on the search bar and download Raspberry Pi Pico RP2040.

Following the installation process, I selected the board by navigating to Tools > Boards > Raspberry Pi Pico/RP2040 > Seeed XIAO RP2040.

Then i modified the code for blink LEDs

void setup() 
            {
              pinMode(26, OUTPUT);
              pinMode(0, OUTPUT);
              pinMode(1, OUTPUT);
            }
            // HIGH and LOW are the voltage levels
            void loop() 
            {
              digitalWrite(26, HIGH); 
              delay(100);                      
              digitalWrite(26, LOW);   
              delay(100);
              digitalWrite(0, HIGH);  
              delay(100);                      
              digitalWrite(0, LOW);  
              delay(100);  
              digitalWrite(1, HIGH);  
              delay(100);                    
              digitalWrite(1, LOW);  
              delay(100);              
            }

This was the results