Today I begin Week 04. of Fablab Academy and this week is about Electronics production. In this week I'm using a new machine, the Precision Milling Machine and have to do some new assignments. So lets begin with this week journey. As I did last week, I will start by sharing some important information about the machine were using.

For this week assignmets I have to:

• Characterize the design rules for your in-house PCB production process
• Make and test a microcontroller development board
• Personalize the board

Equipment, material and software I will be using:

• Precison milling machine / CNC router
• Copper PCB board
• Soldering station / soldering iron
• Soldering tin

What is a CNC router?

A CNC router is a subtractive manufacturing process that uses a rotary tool to remove material from wood, expanded polyurethane foam, plastic, and soft metals. A CNC router typically has a gantry-style construction where the spindle travels left and right along the x-axis and back and forth on the y-axis. A CNC router is different from a standard CNC mill because it is not designed for high-speed cutting of complex geometries in hard metals. CNC routers are generally less stiff than standard CNC mills and when harder metals are being cut. For that reason, they are limited to cutting softer materials like wood, soft metals, and in some cases steel. It must also be noted that routers have limited travel along the z-axis, they cannot create deep holes and slots.

How Does a CNC Router Work?

It works by moving a tool to specific x, y and z coordinates throughout the machine's available working area. A router or high-speed spindle with a cutting tool then removes material at the desired locations. Different cutting tools can be used depending on the material and the feature being machined. These tools can be manually or of a more advanced machine, an automatic Tool Changer can swap out tools.

Data from: CNC router

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What is a copper bakelite board?

A standard printed circuit board (PCB) relies on a base layer typically made of fiberglass. While this material operates well in normal conditions, it often sustains damage in high-power applications. Metal core circuit boards, such as copper core PCBs, offer the durability and conductivity you need for high-temperature uses.

How are copper PCBS made?

Copper core circuit boards are a type of metal core PCB. With their layered design using a copper base, these PCBs offer superior thermal conductivity.

• Base layer: The base layer is made of a copper substrate that offers high thermal conductivity and heat transfer.
• Thermal insulation layer: Copper core PCBs use prepreg or another high thermal conductivity insulation to improve heat transfer.
• Circuit layer: Copper foil makes up the circuit layer, and these often range from 1 to 10 ounces.
• Dielectric layer: An added dielectric layer absorbs the heat that travels through the circuit layer and sends it to the copper substrate for dispersion.

Data from: PCB boards

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What is a Soldering Station?

Is an electrical device used for soldering tasks. It comprises soldering tools connected to the control unit, desoldering tools, soldering tip cleaners, holders, stands, and other accessories. The control unit consists of temperature adjustment knobs, display areas and an electrical transformer.

• Soldering iron tip: is made of copper for efficient heat transfer and coated with iron for durability.
• Foam grip: reduces the heat sensation on the handle as one is soldering.
• Holder or stand: holds the soldering iron when it's no longer in use. It ensures safety and reduces any chance of an accident.
• Temperature adjustment knob: Controls the temperature such that it's at the recommended temperature of 316⁰C (600⁰F).
• Display area: It displays the temperature of the soldering iron.
• Desoldering tool:Removes solder from the joined metals so it can be reworked.
• Power switch: Use it to switch on/off power to heat the soldering iron.

Data from: Soldering station

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Soldering Tin

Is ideal for applications where there are delicate temperature requirements for soldering. When tin is added into the wire, it provides a lower melting temperature. A lower melting temperature for solder is required when the parts being joined can be negatively impacted at higher temperatures.

Is commonly used for electronics where heat sensitive components will begin to melt, crack, or warp at varying high temperatures. It also provides good electrical properties as well as mechanical strength. The solder ensures that electronic components are joined securely to contact points. Since the tin lead wire is lightweight, it won’t put any unnecessary stresses on components.

Concerns with Tin Lead Wire

Always ensure that proper ventilation and personal protective equipment is used when using tin lead wire for soldering. Lead is considered hazardous. So, the tin lead wire materials that are not used should be disposed properly in approved containers.

Data from: Soldering tin

Group Assignments

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1. Knowing about Quentorres. swd+uart adapter+hello board - xiao rp2040

So, for my first assignment for this week I started reading about Quentorres. This are some important things I learn:

• This board helps you learn how to program.
• So I took a look at the different components and try to identify some of them in the board.
  • Compoments I identify:
  • Led
  • Buttom
  • Pins
  • Some microcontrollers
  • Compoments I didn't identify in the board:
  • Some microcontrollers
  • Switches
  • Connectors
  • Resistors
• It's necessary to add libraries so we can program the board.
• Connection orientations are important, you got to know the cable, how to connect it and where.
• There are different ways to program a board.

Data from: Quentorres

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2. Setting the CNC Router

As I did last week, it's necessary to set the machine so it can work properly and have communication with my PC:

• I google the Candle software that I need for the CNC router.
• You can download from the next link: Candle
• Scroll down and look for the version and the operative system in the pc.
• Once you download the candle version need it, decompress the .zip folder and look for the file app.
• Theres´s no need to install, just double click.

Generating the G-code

Once you are ready to use the machine, we have to generate de G-code:

But before we continue, lets get to know about G-code. G-code is a type of programming language used in the areas of Computer Numerical Control (CNC) and 3D printing for instructing machine tool movement. It is written in Computer Aided Manufacturing (CAM) software to provide automation instructions to various machine functions and tools.

G-code stands for geometric code. G-codes are also known as preparatory codes for CNC machines. The instructions provided by G-codes tell the machine tool how to move in the (X, Y, Z) cartesian coordinate system. n addition to the location instructions, the G-code also provides many other input such as speed and angle in the rotational axis, tool length offset, start point, stop point, feed rate, wait time, etc. G-codes work in tandem with M-codes. M-codes stand for ‘Machine codes’ or miscellaneous codes. M-codes provide instructions on various functions of the machine that are not relative to the movements. An example of M-code is M0, which means an end to the program.

Data from: G-Code

Here are the steps to generate the G-code CNC router machine requires:

1. We are going to use the traces files from the MIT Fab Academy. (You can find this files, in the file section below)
2. Then we google mods MIT, Mods. This is going to help us generate de G-Code.
3. Now we follow the next steps:
• Right click on the page.
• Click on programs.
• Open programs.
• Scroll down and click mill 2D PCB.
4. Look at the images below to have a better understanding.

A few more steps, we are almost done:

5. In the page it shows in the first image, scroll down and find read png.
6. Click on select PNG file and search for the file need it. In this case the Quentorres file.
7. Next go to the rigth and find the v-bit calculator and click on send calculated settings.
8. Then go a little to the right on mill raster 2D section and click on calculate.
9. Finally, this will open a new tab on your browser and it'll download the file with thw G-code.
10. I repeat all this two more times for the other parts of the design. Didn't know that I had to do it in parts.
11. Important: I change the tip mill so when I generate the G-code I change step 7. Instead of V-bit calculator I use mill outline (1/32).

Place the board correctly:

An important part is placing the board correctly in the CNC router. Just a few things to consider:

• Make sure the board doesn't move.
• Use the correct mills.
• In case you have to change the mills, use the right tools to change them.
• Be careful, the tip mills are delicate and they can get damage if we let them fall.

Using candle software and the G-code file:

Now that we are ready, we are going to use the Candle software and the G-code file to start cutting the board.

1. Open candle software and click on options.
2. Click on the buttom with a circular arrow. If no error is shown, it should appear COM7 in the port space. Now, what happens if it doesn't:
• This is in a windows OS. Click the windows buttom and type device administrator
• Rigth click and select update driver, wait for a few seconds a try again clicking the circular arrow buttom.
3. FYI, make sure the CNC router is connected to your laptop.
4. At the end of the screen you'll see the lines showing the G-code.

Setting the coordinates:

In this part we have to set the x,y and z coordinates. So we must use this buttoms (look at the image below):

• Use the arrows at the left to set the x and y coordinates.
• The arrows at the right are used to set the z coordinate.
• The coordinates shown at the rigth part of the second image should be in 0. (first rectangle)
• In case the coordinates aren't set in 0 we must use the buttoms shown in the second red rectangle.
• Finally press the start button at the bottom of the screen and of everything is ok, the CNC router will start working.
• Now wait for a few minutes, in my case 18 to 20 minutes.

Individual Assignments

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3. Practice time

In this section of the web page you'll see some pictures of my practice time soldering. Just a few advice based on my experience:

• Get comfortable.
• Get familiar with the equipment.
• In my case, it was my first time soldering so I ask for advice on techniques and how to hold the equipment (soldering iron/tin).
• I use a magnifying glass (my best friend this week) cause the board and components are really small.
• Enjoy this time and practice. FYI, for me what I thought it will be a 2 hour practice it turn to 6 aproximately 6 hours in 1 day.

Here are some pictures and a short video of the results I got of my practice time:

In the video you'll see im using the microscope to get a better look at the results. It didn't went that bad.

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4. Final engraving and soldering

So it's time to begin my final assignment for this week. Now that i had some practice with the CNC machine and soldering, I started with:

• Engaving the linetraces and linstrace exterior.
• I begin by generating the G code
• You can find the G code files in the files section of week 04.
• Based on the results less than 0.013 in. the traces won't be made.








• For the next part of the assignment I engrave the Quentorres design to the PCB board.
• I generate de G code the way I explain above. Remember to use the right options in accordance with the tip your using.
• I repeat this 3 times one per png file.
• I first did the main circuit, the the drills and finally the line traces.
• For the main circuit I use a shape V tip mill and for the drills and line traces a bit tip.






• The components I use are:
• Seeed Studio XIAO-ESP32-S3.
• Led blue clear 1206 SMD.
• RES 1K OHM 1% 1/4W 1206.
• RES 470 OHM 1% 1/4W 1206.
• CONN HEADER SMD 10POS 1.27MM
• Push button.

Testing my results

The moment of truth. I'm going test my soldering and see if it works, no short circuit.

• First of all, connect your board to the PC using a type C cable.
• I open the Arduino Ide, I had already downloaded it.
• In case you don't have it, you can use this link to download it: Arduino IDE
• Google Wiki Seeed Studio, especifically go to this link: Xiao ESP32S3
• Scroll down the page and copy the link to add the ESP32 board package to the Arduino IDE
• This is the link: ESP32 board
• Now click on file then preferences

• Paste the ESP32 board link in the Additional boards manager URLs space on the Arduino IDE and click on Ok.
• On the Arduino IDE click on Tools then Boards and then boards manager.
• At the left side of the screen click on install the latest version of the ESP32 board.
• At this point I waited like 10 - 15 minutes.

• Now go to File then 01. Basics and Blink.
• Clic on the Upload button.
• Wait for it to compile.

Here's a short video of the test:

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5. Problems during this week.

This has been a very interesting week. As you know this week assignments were related to electronics production. It was my first time engraving a PCB board and soldering.

During week 04. journey I had some problems but the good thing is that I learned about them. Let me share them with you and what I did to solve them:

• My computer didn't recognize the CNC router, when I open candle software and click on the round button it didn't recognize the port. This is what I did:
• First of all, i'm using Windows operative system.
• I open the device administrator from the control panel.
• Scroll down and look for the port options.
• Rigth clic it and select update drivers.
• First time it didn't work so I try it a second time and it work.


• Another problem I had was when the CNC router engrave and finish the process but it just did part of it. I thought I used the wrong design. For this part:
• I check the design, it was the correct one.
• I check the mills, it was the right one.
• Verify if the board was set correctly and it was ok
• Finally I saw that the base were I put the board wasn't flat. The board was lifted in some parts, so I change the base.


• P.I.C.N.I.C error, I started to engrave de board and realize that chip, "viruta" was lifting.
• I pause the CNC router
• I checked everything the board, the base, the program, the design, everything seemed ok..
• What I forgot for a moment was that the tip mill wasn't the correct one.
• So I stop the CNC router, change the tip and start again.

Final part

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Files

In this part you can download the files that I use during this week assignments.

• Designs for the CNC router: PNG files
• Designs for the CNC router: NC files
• Arduino IDE: Blink test code

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Conclusions

What did I learn in this week?

• Again, document as you go. Make it a habit.
• Don't forget to compress your images and videos, make sure every commit is under 10 mb.
• Know your components, materials and equipment.
• Make time to practice soldering.
• Get to know the machine.
• While you are soldering take your time.
• If necessary use tweezers to place the components and a magnifying glass, this really helped me.
• I use a microscope to see my results of my practice and final soldering part, it helped a lot.