PCB Etching, my first!

In my fourth semester, my group mates and I had to make two mini projects. Our topics that we choose were “a twilight” switch and “A heat sensor with fan cooling”. After buying the components, we had to etch the copper clad board. Instead of connecting the components with wires, we trace a path on a copper clad board and etch(which I am going to explain), then drill holes for the components to be mounted and then solder with a soldering gun.

For PCB etching, you need:

  • A copper clad (Available at any store that sells electronic components, I got mine from Lamington road for Rupees 10 )
  • A permanent ultra fine OHP/DVD marker. (I used a cello permanent ultra fine OHP/DVD marker, Rupees 15 )
  • A ruler
  • an eraser
  • A pencil
  • Ferrous chloride powder. (75 grams for Rupees 25)
  • 100 ml water
  • toothpick
  • tracing paperw
  • A tray or a broad container of 5 cm in height and as for width and length: just enough so that your copper clad board can fit.
  • cotton ball
  • acetone (Nail polish remover)
  • rubber gloves
You can build your path on diptrace(or any other software), and print. On a tracing paper, trace the path using a ruler. Using a toothpick, make holes where your components are to be mounted(This is shown on your print out.)
Now, on your copper clad board, make a grid using your pencil. Each square on it should be 2.54 mm thick(Yes, it is a tedious process and you have to be meticulous in making it). Align the holes that you made on your traced sheet with the grid that you made. Mark the holes using a pencil.

Trace the path perfectly, use the grid that you made. Be as perfect as you can. The path traced should be approximately 3mm-5mm thick. Don’t worry, if you make mistakes, you can erase them.

After your done and happy with the path that you have traced, draw it again using your permanent marker. It should look like this.

Image

Add  50 grams ferrous chloride to 100ml water in your plastic container or tray and place the tray near your window where the container/tray is exposed to sunlight. Don’t panic when you hear “whoosh”, its an exothermic reaction. Your etchant is ready!

Image

Put in your copper clad board, with the path you traced facing you. And wait for 30 seconds, you will see bubbles on your board. Shake your container/tray horizontally, but not vigorously for about 3-5 seconds.

Image

You will see some of the copper dissolving. After about 30 seconds, shake it again.

Image

At intervals of thirty seconds, shake for 3seconds till the copper dissolves and you are only left with the path traced by you. This should take around 8 to 10 minutes. Make sure your around while your etching, and don’t leave it in for more than 15 minutes.

Image

Remove your board with your rubber gloves on quickly, and pour drinking water over it. And this is what you get.

Image

Put some acetone on a cotton ball, and use it to wipe off the permanent marker ink. You are left with copper that you have traced! And you’re done!

Image

Drill holes in the places that you’re supposed to, mount your components and solder.

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And you’re done!

Refrences:

Walter C bosshart: PRINTED CIRCUIT BOARDS, Design and Technology, Publication Tata McGraw-Hill publishing company Limited (24th reprint 2002), Regensdorf, Switzerland.


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15 responses to “PCB Etching, my first!

    • Can you please elaborate on the “rules of PCB design?” IF its on how to draw/trace then this post focuses only on for PCB etching at home.
      So it would help if you could elaborate.
      Thanks for your suggestion though.
      -Priti

  1. You made your project in third sem itself!!! Amazing yaar!!! 😛
    Beside dat you have written good, picked up some tips from here. 🙂
    Keep blogging!!! 😉

    • PCB hand drill method is an okayish to good method.

      The needle breaks if you apply too much force, so make sure you buy 3 needles, just in case. But you do face this with the machine too.

      The hand drill is cheap and Easy to carry around. So I use it. Sometimes I need a bigger hole for the pins and I use the hand drill, it’s so much easier. And my college machine drill never works when I need it.

      But with the hand drill you need to put in effort, and your hand hurts and you just have to get the hang of it.

  2. Pingback: How to work on your project? (Mumbai University) | Priti's Pretty Blog·

  3. A good writeup, readers be careful though since FeCl3 is toxic and causes stains even on SS. Be very safe use gloves and glass.

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