8. ELECTRONIC 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

GROUP PROJECT

The Week 8 group assignment provided a comprehensive overview of PCB production processes, focusing on tool characterization and alternative fabrication methods. We evaluated the performance of three milling tools on the Roland Modela MDX-20—1/64” flat end mill, V-bit 0.2mm, and V-bit 0.1mm—establishing their minimum clearance capabilities as .015 inch, .010 inch, and .005 inch, respectively. All tools successfully produced the required trace widths, highlighting their suitability for different design densities. Additionally, we explored the use of vinyl cutters like the Roland GX-24 GS-24 for flexible circuits, demonstrating versatility in adapting PCB designs for various substrates. The assignment also introduced workflows for Trotec laser cutters and X-Tools F1 Ultra fiber lasers, expanding our understanding of advanced PCB fabrication techniques. Overall, this experience enhanced our ability to optimize PCB production workflows based on specific design requirements and available resources.

Group assignment

INDIVIDUAL PROJECT

As part of my individual project i need to design and fabricate a microcontroller . For that i have Decided to Manufacture the pcb that i have designed in the Previous week .

For that First Opened My Kicad File and i Exported the File as Gerber File .

In my case i was having an extension to export as Gerber so i Used that . You could refer My Previous week to know more about the Extension .

Next the Step is to Make the Gerber File to PNG Format so it Could be Milled . For that we used Gerber2Png (A fablab kerala site ) That helbs to convert the gerber files to png . where it gives different data for drills and mills and cuts .

Gerber2PNG

https://gerber2png.fablabkerala.in/

After Opening the Website Upload your Gerber Files in the Website . Make sure to Upload All the Gerber Files . Once you Upload it Will Give you Different Png Files for Traces , Cuts and Drills .

Here is the Step by Step Process of Converting the Gerber Files to PNG :

1. Open the Gerber2PNG website and click on “Choose Files” to upload your Gerber files

1. Select all the Gerber files from your project folder (files with extensions like .gtl, .gbl, .gto, etc.)
2. Change the Quick Setup To Generate all .
3. Click “Upload” and wait for the conversion process to complete . Then click on Generate PNG.
4. Download the generated PNG files for traces, cuts, and drill holes from the results page

These PNG files will be used in the next step for milling the PCB using the Roland machine.

You could Either Download as Zip or you could download as separate files as shown in the Right side.

Next step is to Mill the PCB .

PCB MILLING USING ROLAND MDX

Machine Overview

The Roland Modela MDX-20 is a 2.5D precision milling and scanning machine. It is widely used for milling circuit boards but can also mill soft materials like machinable wax or wood. The machine operates as a standard 3-axis CNC device with stepper motors controlling the X, Y, and Z axes.

Technical Specifications

• Build Area: 203.2 x 152.4 x 62.4 mm
• Spindle Motor: 10W DC motor
• Spindle Speed: 6,500 RPM (fixed)
• Chuck Size: 6mm or 1/8 inch OEM
• Compatible Materials: Copper-clad FR1 boards, machinable wax, resin, chemical wood, aluminum (A5052), brass
• Tool Types: Flat end mills (e.g., 1/64”, 1/32”) and V-bits (0.1mm and 0.2mm)
• Interface: RS232C serial connection
• Software Workflow: Uses Fab Modules or Mods to generate toolpaths from monochrome PNG files

For that You should open the MODS software and then upload the PNG . Mods software is maid by Neil of Fab academy .

First You want to Paste the sticker on the board so that it can be removed and the board sticks to the sacrificial layer . So it can be milled .

In the below Image i have shown the bottom side where i have put the sticker and i have cutted the edges

Then keep the board in the roland pcb milling machine and you could mill . like the one below .Press the board until you are sure that the board is gummed properly to the layer .

For milling i have used the 0.2 mills v cut 60 deg . and we have kept the cut depth as 0.1 m .

Below i have attached a basic workflow to setup Roland . (prepared by my batchmate Noel)

HOW TO CHANGE BITS

Use the Alen key to change the bits .

Remove any watch or wearable materials if you have in your hand before the Removal of tool. Steps to Remove

Use Both hands for Removal : Use one hand to Hold the tool so that it does not drop down and use the allen key to loosen the screws at both sides and remove the Tool .

MODS SOFTWARE

MODS is a browser-based tool for controlling digital fabrication machines. For the Roland MDX-20, it allows you to upload PNG files and generate toolpaths for traces, drilling, and cutting operations. The software provides important parameters like cut depth, tool diameter, and feed rate that need to be set correctly for successful PCB milling.

After the hardware the next step is to setup the software side . For that i used Mods .

First you have to upload the png file that you have generated through gerber2png to mods .

(In my case i have forgotten to download the outline file ) so please make sure that all files are there .

You could set the bits as below . select (1/32) for cutting and v cut 0.2 mils 60 deg for engraving .

Changing Bit

click on edit position to change bit when you are about to change bit .
Steps : 1 : Click on view on the Roland machine and check Whether the green light is off . 2 : Then click on Position to change bit so that the bed positions to inside and the tool lean forward so we could easily change .

Then follow the steps as mentioned in this document for the tool Change .

DRILL AND CUT BIT VALUES

Below is the calculations that i used for drill operations . as per the bit 1/32 .

After you are entering the Tool parameters . go to this module mill raster 2D (below ) and check whether the ones are same as the one we have inputed before . Then click on calculate . Then click view so you could see the item .

DRILL BIT NOT DISPLAYING

In this case you could adjust the tool diameter on mill raster 2D module until it displays . The issue is occuring because the hole diameter is less and we are using a tool that i bigger than the hole diameter . (thats what i understood ) . here we are kind of fooling the milling machine by reducing the tool diameter we are overwriting its settings and making it believe that the it could cut through the hole . So when it reaches a certain diameter the hole starts displaying .

This is the view that you would get . Check whether the traces are correct .

The below is the final step . after all are ready click send files button on the websocket python serial module .

This is the final setup Or how The MDX module looks like .

SETTING UP THE X,Y,Z AXIS

To set the x and y axis . you could enter it on the MODS software . But When it comes to Z axis There is a requirement of manually setting the bits up . For that follow the steps below .

1. When you are setting the bit . tight one side fully and keep the other side half loosed as we want to set the z axis .
2. Then move the axis to origin . and slightly adjust the x and y so you could work comfortably with the bit adjustments for z axis .

The image below shows how i moved the to side ( x and y was adjusted ) . Then i lowered the z axis so it touches the pcb . Make sure the bit is touching the pcb . slightly press the bit so it is made sure the bit is ready for the function .

3 . Then Tighten the bit so that it is ready to go .

Now move the tool to the origin .You could press the down arrow so that it mills down slightly to make sure the tool is entering properly and is ready to engrave .

PCB milling

After the axis is ready next process is to run the program for milling andthe below one is the engraved ones .

Then i cleaned the dust above using a vacum cleaner .

Then i was ready for cutting . For that i change the tool to 1/32 bit .

The tool was not Properly Tight . so This happened . Make sure That the Tool is Properly Tight .

Then i have tightened and i have done again .

What to do in Case of Emergencies Like This ?

• Click View to stop the task
• Then click on close socket in the module , check the image below .

• Then press up and down arrow key together in the roland machine to reset the job

• Now the job is Reset .
• Now correct the errors . like in my case i set the position of the bit to origin and tightened the bit.
• Then clicked the open socked and i continued the work by sending file again from the origin .

First i have done the Drilling Operation and then i have done the Cutting one .

FINAL

This is the Pcb board layout that you got as final .

The next step is to Put The components On the Board .

Component placing

For That You want to know which all components are used in this . For to generate that easily i have used an extension to generate the Bill of Material (BOM) .

Go to kicad Opening Page . there is a Plugin Manager . open it and add The Interactive HTML Bom . click on install and then click on accept Pending changes .So it is Installed .

Then go to the PCB editor Tab . Where you could find an option called BOM generator on the top right corner . click that and generate BOM .

Then you would get a BOM like this .

The next step is to request components from the inventory. Fabstash, which is the inventory system of Fablab Kerala, allows you to add all required components to your cart, submit the request, and print the BOM.

After printed the BOM get the components from the inventory and stick it next to BOM .

This is the component list that i have used .

I used tweezers to pick the components and i placed them on the board .

At first i have sanded the board to get a better finish .using the tool shown below

The below one is the PIN OUT Diagram of the board

Then i Took this 3d image as my reference for Soldering .

We use a soldering station to solder . The below one is the image of our station .

Then i have turned on the exhaust as shown below it sucks the harmful gases .

THINGS TO NOTE

Before Soldering make sure you wear a mask . As the gas is dangerous for you health . Make sure you add water to the soldering station . Make the soldering station Temperature to 300 +

The airblower used for desoldering ( temperature is recommended to be 350)

Then i have Fixed my board as below .

Next step is to add components for that i have placed my component list with my components on side so i could pick and place .

The below image is me looking the terminals of led in a microscope . The one side with green means that should be connected to ground .

The below image is me soldering the PCb

TIPS TO REMEMBER FOR SOLDERING

• Always clean the soldering iron tip regularly using the brass wool cleaner to maintain good heat transfer
• Use appropriate amount of solder - not too much or too little
• Hold components in place with tweezers or helping hands while soldering
• Check for cold joints (dull, grainy appearance) and reflow if needed
• Let joints cool naturally - don’t blow on them as it can create weak connections

HOW TO SOLDER

• First heat up the soldering iron to the correct temperature (around 300-350°C)
• Touch both the component lead and the pad with the iron tip to heat them simultaneously
• Then apply solder to one side of the pad without the component using just solder wire. Then bring the component nearby and use soldering iron place the components one side fixed to the solder .
• Make sure the component is aligned . Then place solder on the next leg . if there are many legs solder diagonally so the component stays fixed .
• The solder should flow smoothly and form a concave fillet shape . ie you should bring the solder to pad first then feed the soldering wire to the pad by touching the solder.
• Remove the iron and hold the component still until the solder solidifies (1-2 seconds)

This is the final pcb that i have made .

Now the next Process is to inspect the PCB . For that i used a microscope to inspect through the traces . and verified whether the soldering is ok .

The next step is to check the pcb . For that at first i checked using multimeter . for any short circuit . i have done the continuity test with the 5v and ground and then 3.3 v and ground . if the beep sounds comes then the meaning is the power is returning back to ground or the circuit is short . In my case there was no sound so it was tested ok .

PROGRAMMING THE PCB

First i have checked a blink test . Using arduino and it was working . Connect the board and change the arduino settings , board and the port ones .

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
}

The below is the Result .

The next thing i have checked the switch .

After writing the code click on run as shown in the red dialog box and then the code is encoded to board and it is ready to work .

The video is shown below .

Then i have made a Flexible PCB

this is me testing the flexibility.

In the below video i have tested it with the basic programs of Led Blinking and Switch .

switch

Conclusion

This week focused on mastering the PCB production process using the Roland Modela MDX-20 milling machine. The workflow involved converting Gerber files into PNG format using tools like Gerber2PNG to prepare for milling, followed by precise toolpath generation and machine setup using Mods software. Through practical tests, we characterized the performance of different tools, including the 1/64” flat end mill and V-bits (0.1mm and 0.2mm), successfully achieving trace widths of .001, .010, and .020 inches and clearances as fine as .005 inch. The final PCB was fabricated, cleaned, and inspected for quality, followed by component placement and soldering using best practices to ensure functionality. The week concluded with programming and testing the microcontroller development board, validating the successful integration of design, fabrication, and assembly workflows. This comprehensive experience not only enhanced technical skills but also established a robust foundation for future electronics production projects.

FILES

My Gerber2png files

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Last update: March 19, 2025