4. Electronics Production

This week I learned to make PCB using a milling machine and perfect my soldering skills. You can review the Group page in this link.

Making the Files


For making the files compatiblle for the machine (.rml) we will use the software called Mods.

    STEPS:
  1. Right Click
  2. Programs
  3. Open Program
  4. Roland SRM-20 mill, click on mill 2D PCB
If you made everything correctly your screen should look something like this:


For the traces
Now you can upload your image (PNG) on the left block after that, click on mill traces (1/64) just below, fill the parameters of the tool and the offset number (how many times it makes the streak). Change the speed if needed and calibrate the origin in X:0, Y:0 and Z:0. Activate the toggle bar for download the file. Finally click on Calculate to get the file in .rml.

Aditionally it will pop up a Window with a preview of the engraving trajectory.


For the cut
Repeat the first steps of the Mods, insert the CUT file and click on Invert because the black part is the one the machine performs its operation. Click on mill outline (1/32). Activate the same toogle bar, change the origin to 0's, change the tool preferences and click on calculate.

Files

Using the machine


Now that you have the files you can start preparing the milling machine.

Steps

1. Install the drivers/software


CMA1200

For using the SRM-20 we need a control software and a Driver.
The control software is called VPanel (Click here)
And this Driver

2. Prepare the Copper sheet


CMA1200

  • Cut in MDF a safety board
  • Add double-sided tape to place the copper on the board
  • Place the cupper on the board
*Note: the tape can't be overlaped and it has to be in all the board

3. Tools


CMA1080

We are going to use a 15 degree V-bit for engraving and a 0.8 mm end Mill for cutting.

4. Software


CMA1390

We can move the axis by clicking the arrows, set origins X/Y and Z on the top right of the screen, turn off/on the spindle, move to the origin in the bottom and in the center change the aproach speed.
For loading the files and start cutting/engraving is in the Cut part, in there you can add the engraving file (complete the process), delete the engraving before adding the cutting file.

5. Calibrate Roland SRM-20


CMA1390

  1. Screw the MDF with copper into the machine
  2. Open the software and connect it to the Roland
  3. Put the engraving tool
  4. Start by calibrating the X/Y axis about a centimeter of the bottom left corner
  5. Start lowering the Z axis near the plate (change speed aproach if needed)
  6. Loose the tool and let it touch the plate (tighten again)
  7. Save the coordinates X/Y/Z
  8. Move the tool up for safety before you start the process
  9. Start the process



When finshed verify the engraving
  1. Move up to change the tool
  2. Repeat process 3, 4, 5, 6 and 7
  3. Erease the engraving file and load the cutting one
  4. Start cutting
After all is done verify the copper plate and the tracks

     

Parts of the board and Soldering


It's been a lot since I solder so I practice soldering on a test board.


After getting my confidence back it is time to prepare everything I need.
On the schematics we can identify all the components and the value needed. In this case: we will only use:
  • XIAO RP2040
  • Push Button
  • 1: 2.2K Resistance: with the letter R5
  • 7: 1K Ressitance: with the letter R(1-7)
  • 3 LEDs: with the letter D
  • Pin Header: 1 of 6 and 2 of 5
We can see in the image below all the components before the soldering.

Now we are almost ready to start but there is something to do first. Put some black tape on the back of the XIAO because it has some conections underneath that we don't want to touch anything. And verify the polarity of the LEDS, you can always check the line they have (the line is the anode [-] and compare the conections with the diagrams conections).


Now we can SOLDER

Code and test


After we solder and verify everything is well, we can connect it to a computer, open Arduino and load a code (follow steps).

    STEPS:
  1. Open Arduino
  2. File > Preferences
  3. Paste this link https://github.com/earlephilhower/arduino-pico/releases/download/global/package_rp2040_index.json in Additional boards manager URLs
  4. Tools > Board > Board Manager
  5. Search for RP2040 and Install
  6. Select Board and Port
  7. Upload your own code
CODE
This is a code given by instructor Huber Giron. What it does it a blinking the LEDs from the bottom every second and when I push the button the third LED start blinking at the same rate.

Files

Copper tape


For my Final Project comfort is a very important part so trying and getting used to felxible circuits is essential.
After making a lot of test with different speeds, depths and pressueres this is my conclusion:

Only Copper
This was a complete FAIL in all the way, no matter the parameters it always get ripped off and start creating a bulk of copper.

With Vinyl
This was great at first with parameters of pressure 15, speed 2 and depth 3. It got all the cupper and Vinyl Cut and was kind of easy but when we get in the soldering part the heat ripped of and lose the Vinyl adherence.


With transfer paper
With transfer paper we got a great cut was dificult to clear the tracks but possible, the main issue is that it can't be placed anywhere else. So I didn't try to solder it.

Transparency Film
Was the most perfect test, with parameters of 20 pressure, 8 speed and 1 of depth we can get a clean cut of the copper and thanks of the transparent material we get a clean look, it was one of the easiest to ripp off. After I started to solder it it was looking good, but the real test was to program the same thing to verify its performance.