PCB Etching Tutorial

DIY PCB Etching : Using Chemicals

Chances are you've probably seen a PCB before and it might of looked a little something like this

[Insert a picture of an example of a PCB maybe a Raspberry Pi or an Arduino etc]

The most important part of a PCB is the traces which connect the components to each other. These traces made in a CAD program for PCBs like : Eagle CAD , KiCAD etc

[Insert Picture of traces here]

This tutorial will show you how to make a simple single sided PCB using a chemical method. In summary the traces will be transferred and covered in a solid copper board , then the parts of copper not needed will stay expoxed. Finally the parts not needed will be removed with chemicals.

[Insert picture of before and after here ]

Materials Needed

• Single sided copper clad board -- [[ https://www.google.com/search?q=copper+clad+fr4&ie=utf-8&oe=utf-8]]
• Circuit board trace layout in a printable format (pdf or postscript ps works, design this with an EDA program)
• Glossy Inkjet Photo Paper (to print the traces on)
• Iron or press
• Etchant chemical
  1. Ferric Chloride Solution (to dissolve the copper from the board)
  2. Muriatic Acid
• WetorDry paper
• Container to put PCB in with chemical solution

Steps

If you are using Ferric Chloride(FeCl3) foretchant, then start heating your etchant to 50C

1) Preparing the Copper Board: Clean It

Make sure to clean any junk from the copper board before beginning the process!

• Use WetorDry paper / fine sand paper to clean the PCB under water until it turns pink
• Wipe off water with a clean towel
• Use acetone to remove oils from PCB

[ insert Cleaning pics here]

2) Printing the Traces:

Grab your Laser printer and print the traces onto the glossy inkjet photo paper.

• we used walgreens 8.5x11 stock inkjet photo paper with fine results
• We used the Noisebridge Brother HL-5470DW and generic Laser printer toner with fine results
• Make sure your print driver isn't scaling or distorting the circuit layout
• Use monochrome and highest resolution possible for your printer

The printer operator should also take this opportunity to provide feedback to the circuit designer:

• Make sure the design traces are thick enough for this process (XXmil/XXmm minimum trace width with 20mil/0.508mm minimum clearance)
• Make sure the export file is mirrored. The Laser Printer toner is going to 'transfer' to the surface of the copper clad and become unmmirrored in the process

[insert printing pics here]

3) Transferring the Traces to the PCB:

  - Press down the glossy paper with the design onto the copper PCB 
  - Use a hot iron to press down glossy paper to the PCB [INSERT PIC HERE OF IRON PRESSED]
  - After the glossy paper stick onto the PCB submerge the two in a tray of water and gently press down the paper so it peels off leaving the trace on the PCB 

 [insert PCB iron down pic here]

4) Get Rid of the remaining Copper

  - Place the Ferric Chloride Solution Bottle  inside tray of hot water (this will heat the solution and make the PCB copper to be dissolved faster) 
  - Pour some of the solution into a tray along with your PCB 
  - Check the PCB every 5 or so minutes to check if the copper has been fully removed

[insert PCB blood water pics here]