UV LED PC Board Exposure Build
Using 1watt STAR UV LEDs To Photo Expose a PCB
Once the board has been developed, it is time to actually etch the image into the copper. From the exposed board, wherever light was able to hit the board, this will result in the copper being removed. The Etchant being used is Ferric Chloride. The board can either be floated on the surface, with the copper side facing down, or sunk into the etchant.
The etching process will take a few minutes to completely remove the photo-sensitized exposed area. Immerse the copper board, copper side down, in the Ferric Chloride solution and agitate until etching action is completed. The etching process can be sped up by heating the Ferric Chloride solution to a temperature no higher than 55C (135F).
When the etching process is complete, remove the board from the Ferric Chloride etchant bath and rinse with water. The board still has the photographic mask on the copper sections. This is removed with Acetone (common nail polish remover), and finally with a rinse of water.
After the photographic mask is removed from the PCB, you are left with a copper PCB pattern of your circuit. For the test here, we can see the optimal exposure occurs in the second from the right section which is an exposer of 30 seconds. Final drilling of the PCB can now be undertaken to finish off the board.
Introduction – Design – Create Positive Image – Prepare The Board
Expose The Board – Develop Board – Etching – Thoughts