Sunday, November 18, 2012

PCBഎച്ചിങ്ങിനു പുതിയ രീതി


  PCBഎച്ചിങ്ങിനു  പുതിയ രീതി

I learned a new method to etch home-made PCB's. In this method, the PCB is not soaked in etching fluid, instead the copper is removed by rubbing with a sponge. The good things about this method are, you need only very small amounts of etching fluid, and the fluid does not need to be heated.


PCBഎച്ചിങ്ങിനു ഒരു പുതിയ രീതി ആവിഷ്കരിക്കപ്പെട്ടിരിക്കുന്നു ഈ രീതിയിലൂടെ വളരെ കുറഞ്ഞ അളവില്‍ ഫെറിക് ക്ലോറൈഡ് ഉപയോഗിച്ച് PCB കള്‍ തയാറാക്കാം

 


I am preparing my own etching-fluid. To do this, 80 grams of Fe3Cl powder are added to 120 grams of water, so I have a 40% ferric chloride solution at the end. I made experiments with low concentration ( 15-20% ) solutions, and I saw that the process takes too long time, so I am using a min 40% solution. I keep the prepared solution in a plastic (PE) bottle. This bottle will last me a long time because this process needs very little amount of fluid.
 spongesponge


Here are the equipments I use; gloves, a glass bowl, and a small piece of sponge.
sponge


I am pouring little amount of etching-fluid to my sponge, and I rub with it the board surface. If the copper area is large, the fluid color will turn to black in very short time, if so ,refresh the fluid and continue rubbing.
spongesponge


The middle of the board is etched in a one or two minutes, but for the edges you have to rub with sponge for a long time.
sponge


Below you can see the fully etched board.
sponge


– It is economical, and less waste is out
– It is a very short process for small circuits
– You don't need to heat the etching-fluid
Positive aspects of this method are:
Negative aspects:
– Etching large and double-sided circuit boards will take very long time
– Rubbing hard with sponge also removes drawings made with water resist pens.

Finally, my advice is, minimize the copper surface area. Very large copper surface causes saturation of the etching-fluid quickly, and you need to refresh the fluid again and again.

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