How is the photoresist removed from a PCB?
Once the PCB has been exposed the transparency is removed and the plastic film which held the photoresist is peeled away. The photoresist will have hardened and will be stuck to the board. Unexposed photoresist is removed in a solution of 1% Sodium Carbonate*.
Is it possible to make PCBs at home?
Making PCBs at home is probably a dying art, since more and more PCB manufacturing companies will print your circuit board and have them delivered to your home for a reasonable price. Nevertheless, knowing how to make PCBs will still prove useful when making prototypes or replacing that damaged circuit which will take weeks to ship.
What’s the best way to use a photoresist?
A piece of paper is used in between to prevent the plastic film from heating up too much. The transparency sticks to the photoresist with the help of a drop of water. It is then exposed to UV light.
What should the PCB look like after exposure?
The pcb after exposure seems underdeveloped. The white areas in the artwork (where copper should not be etched away) should be dark blue after exposure. However as seen, that is not the case. They seem to have virtually no change in color at all. The tracks are fuzzy.
What’s the best way to expose a PCB?
The transparency is stuck on top and the solder mask blob is squeezed evenly. The same process as before is used to expose the PCB. The unexposed solder mask is removed with tap water and a brush. In some cases the solder mask can stick to the transparency, so a piece of polypropylene film is sandwiched in between.
Why do I need an inverted photo resist for PCB?
The paint needs an inverted image since it is a negative photo resist. This means that wherever UV light hits the blue paint, that exposed area will not be washed away by the developing solution. Now it’s time to expose the plate to UV light. I use two transparent plastic plates I got at “Tap Plastics”.
https://www.youtube.com/watch?v=XCx39v0DSHU