Week 04: Embedded programming

Grupal Assigment

Process Recap

PCB Milling at FabLab Puebla

Three Mini-Mill models are used for PCB milling. They use high-speed rotary cutters to carve copper-clad substrates based on digital designs, ensuring precise pathways for circuits.

Mini Mill Components
  • Front Cover: Protective shield for user safety
  • Power Button: Main power switch
  • Spindle Head: Houses spindle motor for milling
  • Working Table: Surface for securing PCB material
Mini Mill Models

Specifications for the SRM20 model are provided, including operational travels, loadable workpiece weight, operation speed, etc.

Compatible Materials

Various materials can be used with laser cutters, including modeling wax, foam, acrylic, etc.

Safety Guidelines
  • Single Operator: Equipment must be operated by one person at a time
  • Cable Handling: Proper handling of cables
Tooling

Two tools, a 15-degree V-bit for engraving and a 0.8 mm diameter two-flute end mill for cutting, are used for precision in PCB milling.

Parameters for PCB Milling

Drill hole size, material choice (FR1 or FR4), minimum clearance, minimum trace width, and number of layers are critical factors to consider for successful PCB milling.

Planned Parameters

Specific parameters for milling operations, including tool types, cut depth, cut speed, and spindle speed, are outlined.

Image Transformation and Software

MODS software is used to transform images into .rml files compatible with the SRM20 Mini-Mill.

Ease of Use

Despite initial complexity, the process is straightforward, with clear steps outlined for achieving desired results.


Toolpsth process

ROLAND SRM-20 Installation

First I had to instal the program I dowloaded al the links for the software, compatible for the cutter, Its important to say that this specific software is only compatible with windows devices. I accepted all and cliclk in Install option, if everithing works it sold appear a logo like this one in your desktop

Document Creation:

  • Navigate to (Mods) and follow the specified process to open the web program.
  • Upload the files Trace and Cut in PNG format, ensuring to invert the image for cutting.
  • Adjust parameters and press "Calculate" to automatically save the files.
  • Open the program and click "Cut," first tracing and then cutting.

For this part you need to go to (Mods) and follow this exact process to open the web program

You need to upload the files Trace and Cut and in PNG and only for Cut invert the image like I show in the following images

Then change the parameters and press calculate to automaticlly save the files, I personally used offset 2 due 1 layer was to skinny and it can cause a false conection with other components if I didnt sold it carefully and 3 was to thickk and did not leave enough space for the components

Once you locate the acrhives open the program and click cut . First trace and then cut **IF ANY OF THIS ERRORS APPEAR*** Select OK and RETRY and for the machine to continue the cut or shut down de softwar, desconect the cable and redo all this process

Machine Cut:

  • Position the machine with the bottom facing away from the computer.
  • Insert the spare piece onto the copper table, secured with double-sided tape and screws.
  • Utilize software controllers if needed to adjust machine position.
  • Use a V-shaped tool for tracing and a Small Cutter for cutting, as per group practice.

Cut Tools

  • Broca Cortador En V, Pcb, Grabado, Router Fresa Grados Cnc
  • Cortadores Flat End Mill 1, 2, 3.175mm Pcb, Router Cnc

Turn the machine with the bottom behind the computer, then enter the spear pice with the copper table already pasted with doble tape and place it in the machine with screws. If the machine is getting in the way you can move it with the contolers of the software. For the trace you need a tool in V and for the Cut a Small Cutter as in the grupal practice.


Components:

  • 3 LEDs
  • 1 Push button
  • 1 XiaoWeelding
  • 1 of 6 & 2 of 5 Resistors
Qty Description
3 Leds
1 Push bottom
1 of 6 & 2 of 5 Resistence
1 Xiao

Soldering:

  • Take apart the piece and solder without the leftover board, or solder first and then remove the piece.
  • Use masking tape to prevent copper from touching metal components.

Personally I take the pice out just to make sure it was detachable and then I place it back and weeld with the table.


Important to put masking tape so that the copper does not touch the xioms metal components

How to prevent Troubleshooting and Adjustments:

  • Inspect soldered components under a microscope for any issues.
  • Address any non-contacting parts and reinforce connections if necessary.
Little inconviniences

Once I weeld every component I took a closer look with the microscope just to find there were parts that did not toach the board. So I tried to retouch them and accidently I separated the resisence from the final board but thankfully some pices were not directly conected to others so I reforce the pice and everithing worked fine.

Programming:

  • Download the code onto a computer and connect it using a USB- C cable .

Download the example code.

Final