Electronics Production

Group Assignment

1. CNC Router - CNC3040

1.1 Specifications

The CNC3040 desktop CNC machine, with its advanced capabilities, allows the execution of various complex and detailed projects. Here are some examples that demonstrate its versatility and ability to adapt to a wide range of creative and industrial needs and applications.

2. CNC Router - Milling Test

2.1 Preparing the PCB Milling Test File

To test the milling performance of the CNC router for PCB fabrication, I created a test file with traces ranging from 20–25 mil and 25–30 mil. This test allows evaluation of the machine’s ability to accurately mill different trace widths.

2.2 Using FlatCAM for PCB Manufacturing

2.2.1 Generating G-code for Milling the PCB

I decided to use FlatCAM to generate the G-code for milling and cutting the PCB.

First, we import the Gerber files corresponding to the Top Copper layer and the PCB outline.

I am using a V-endmill for milling, with a 3.175 mm diameter, a 30° angle, lenght 26mm, and a 0.2 mm tip.

First, we need to calculate the effective tool diameter. For this, we use the calculator available in FlatCAM.

We can find the calculator in Tool Menu → Calculator.

The result for our Tool Diameter is 0.2188 mm

Next, we need to configure the milling settings. We will use the following parameters:

After clicking Generate Isolation Geometry in FlatCAM, the software creates the toolpaths used to isolate the PCB traces from the surrounding copper.

When you click Generate CNCJob Object in FlatCAM, the software converts the geometry toolpaths into machine instructions (G-code) that the CNC machine can execute.

2.2.2 Generating G-code for Cutting the PCB's outline

Now let's continue generating the G-code for cutting the outline. For that, I am going to use a 3 mm diameter corn end mill.

Now we need to work with the outline, so in the settings the most important parameter is the tool diameter, which is 3 mm.

After clicking Generate Isolation Geometry in FlatCAM, the software creates the toolpaths used to isolate the PCB traces from the surrounding copper.

When you click Generate CNCJob Object in FlatCAM, the software converts the geometry toolpaths into machine instructions (G-code) that the CNC machine can execute.

Now We have both Gcode for milling and cutting the PCB

3. Making the PCB

Now We are going to start making the PCB, so lets keep on mind the following parameters:

Once the PCB is secured with masking tape, we are ready to begin the milling process.

The next step is to select the file and execute the G-code.

Press OK and let's enjoy

Now We are going to continue cutting the PCB's outline, so lets keep on mind the following parameters:

We need to change our tool for the Corn Endmill 3mm:

We need to set the Z axi new home because We changed to tool and the lenght is different

The next step is to select the file and execute the G-code.

And here we have , our first pcb test.

4. PCB Test Results

In the first test with traces ranging from 20 mil to 25 mil, we observed that some areas were not milled properly. This could be due to several factors, the most important being the tool home position and possible material deformation.

In the second test, the results were significantly better. All the traces were milled correctly, so these values can be used. However, it is important to ensure that the Z-axis is properly calibrated and that the material remains flat.

Individual Assignment

5. Microcontroller PCB

5.1 PCB XIAO Esp32 S3 Sense

The PCB board that we are going to manufacture will work with a XIAO ESP32 S3 Sense, and will include one LED, one switch, one SPI port, and one I2C port.

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5.2 Generating the Gcode Files

First, we import the Gerber files corresponding to the Top Copper layer,the PCB outline and NC Drills.

First, we mill the traces on the top copper layer using a 0.2188 mm diameter tool, as calculated previously in our test.

Next, we generate the G-code files using the parameters validated in the previous test.

Now We continue with the PCB's Outline.

Next, we generate the G-code files using the parameters validated in the previous test.

Finally, we generate the G-code files for the drills .

Done, We have all the Gcode that We need for now

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5.3 PCB Fabrication process

Let's begin the manufacturing process by starting with the milling operation.

After setting the Home position. We select the milling GCode

Press OK, and the machine will complete the rest of the process.

We are going to repeat the same process for the drilling and cutting operations.

Finally We have our PCB Board

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5.4 Soldering the components

Now we will continue soldering the different components of our PCB. For this step, we need a soldering iron, solder wire, flux, tweezers, and the electronic components. It is important to carefully place each component in the correct position on the board and apply the right amount of solder to ensure good electrical connections. We start by soldering the smaller components first and then continue with the remaining parts.

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5.5 Testing the PCB

To test the PCB, we will run a simple LED blink program. This program allows us to verify that the microcontroller, the LED, and the power connections are working correctly. If the LED turns on and off at regular intervals, it confirms that the board has been successfully assembled and programmed.

📟 XIAO ESP32S3 Sense - Blink Example 📋 Copy Code

            void setup() {
            pinMode(D0, OUTPUT);
            }

            void loop() {
            digitalWrite(D0, HIGH);
            delay(200);
            digitalWrite(D0, LOW);
            delay(200);
            }
            

The second test is to control the LED using the button, so that the LED turn on when the button is pressed.

📟 XIAO ESP32S3 Sense - Blink pressing a button 📋 Copy Code

const int LED1 = D0;
const int BUTTON1 = D1;
void setup() {
  // Configurar LEDs como salidas
  pinMode(LED1, OUTPUT);
  pinMode(BUTTON1, INPUT);
  digitalWrite(LED1, LOW);
}
void loop() {
  if (digitalRead(BUTTON1) == HIGH) {
    digitalWrite(LED1, HIGH);
  } else {
    digitalWrite(LED1, LOW);
  }
  delay(50); 
}
        

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6. Learnings

During this project, several important lessons were learned throughout the PCB design, milling, assembly, and testing process. One of the key learnings was the importance of proper machine calibration, especially setting the correct tool home position and Z-axis, since even small height variations can affect the quality of the milled traces. Performing initial milling tests helped determine the appropriate parameters, such as the tool diameter (0.2188 mm) and trace settings, which significantly improved the final results. We also learned that securely fixing the PCB material and ensuring a flat surface is essential to achieve consistent milling depth. During the assembly stage, developing careful soldering techniques was important to correctly place and connect the electronic components without creating short circuits. Finally, testing the board with simple programs, such as a basic LED blink and a button-controlled LED, helped verify that the microcontroller, inputs, outputs, and electrical connections were functioning correctly, demonstrating the importance of iterative testing and troubleshooting in the PCB manufacturing process.

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7. Files

Here are the files available for download.

1. Test PCB - Gerber Files: TESTPCB_GERBERFILES.rar

2. Test PCB - Gcodes: TESTPCB_GCODE.rar

3. PCB XIAO ESP32 S3 Gerber Files : XIAOESO32_GERBERFiles.rar

4. PCB XIAO ESP32 S3 Gcodes : XIAOEPS32_GCODE.rar