How To Make A PCB (Printed Circuit Board) - WORK IN PROGRESS

There are a lot of methods used for PCB manufacturing, but for the everyday hobbyist two of them step up in terms of accessibility and quality: making PCB's by photo-etching method and by milling (with a CNC).

This will be about the photo-etching method. Why? Simply because it allows you to create double-sided PCB at a high quality using easy accessible materials.

What do you need?

• PCB Design Software (yes, like Eagle CAD).
• One printer - after some years of testing I've settled down with a simple inkjet printer (higher printing resolution is better) .
• Transparency film - A4 sheets, no matter what brand as long as it is compatible with your printer (one example is the HP Premium Inkjet Transparency Film).
• Photoresist PCB's - you can make your own but it's no worth. You can find everywhere PCB's already covered with photoresist (Bungard Elektronik is one of the greatest manufacturers in this area).
• Sodium Hydroxide (NaOH) for etching the photoresist. Special care is required to prepare the solution: 7 grams NaOH for every liter of water (H2O).
• Ferric Clorhidre (FeCl3) for etching the cooper. You can buy it directly as a solution.
• One UV light source. I use a DIY UVbox which will be discussed in another article.

Additional materials are needed if you plan to make double-sided PCB's, solder masks, silk layers, ...

To create the PCB you need to go trough the following steps:

     1. Create the circuit schematic (using the PCB Design Software).

     2. Based on the schematic, create the board/layout (also using the PCB Design Software).

     3. Print the transparencies for every layer of the board (bottom, top and bottom). Pay special attention on printing the top layer - it has to be mirrored! 

     4. If you are going double-side, align the two layers.

     5. Make a sandwich out of the transparency films and the photoresist PCB. Expose every side of it to UV light. The exposing time depends on the light source. You'll have to make some experiments first.

     6. Etch the exposed photoresist by emerging the board in NaOH solution.

     7. Wash the board with clean water and dry it. Pay special attention not to scratch the photoresist traces.

     8. Etch the exposed cooper by emerging the board in FeCl3 solution. Ideal results are obtained at a temperature of 60C.

     9. Wash the board and solder the components - the simplest PCB. If you're going the hard way you still have to apply the solder mask, silk layer or to solder the vias.