How to make a printed circuit board (PCB) using the UV light LED method.

Step 3 Expose the presensitized circuit board to UV light.

Place the printed transparency on the elevated plastic about 10 inches above the LEDs. The ink should be facing up towards the sky. While the room is somewhat dark, peel the white film off the presensitized circuit board to expose the photoresist. Place the PCB on top of the transparency, photoresist facing down towards the LEDs. Stack about 8-10 textbooks on top of the PCB to make sure the photoresist is tightly pressed against the ink of the transparency. No scotch tape is necessary to hold the PCB down to the transparency.

Turn the UV light box on. We found that exactly 1 minute exposure time worked well. You may have to experiment with different times depending on the height above the LEDs. Turn off after 1 minute.

The photoresist will look exactly the same after it has been exposed to UV light. We could not tell the difference between an exposed board and a non-exposed board.

Note: The first time you attempt to make a PCB, you will most likely fail (we failed literally about 40 times. Darn textured transparency paper!). We suggest buying a large PCB and cutting it into small squares with a Dremel (I also read a paper cutter works fine). This will save you a lot of money.

Comments

[gulyman]

I have that exact C++ book. It's a pretty good one.

[JoeyJunior]

Haha nice, yup that's how I learned C++.