LKO Railroad
- Aug 9, 2013
- 43
- Joined
- Aug 9, 2013
- Messages
- 43
I have made many PCBs with MG Chemicals boards, developer, and etch. The results have always been pretty good. All of a sudden I am getting consistent failures. Nothing has changed in my process. I've tried fresh boards and developer but get same problem.
The boards come out of the developer looking as if they are overexposed. I tried stacking art screens, no difference. I exposed a board for half the normal amount of time and it reacted as you would expect - developing took much longer but ultimately got same result.
There are odd wave patterns across the boards and large areas of complete washout. My glass is flat and the board is sitting tight and flat against the art. When the art and board are viewed during exposing everything looks normal. The washout areas occur in random places and sizes from board to board.
For the life of me I can't find anything different from how I have always done this. Any clues?
(There is some residual water on this board. Very noticeable on the left. Sorry, I didn't dry it well before taking the picture.)
The boards come out of the developer looking as if they are overexposed. I tried stacking art screens, no difference. I exposed a board for half the normal amount of time and it reacted as you would expect - developing took much longer but ultimately got same result.
There are odd wave patterns across the boards and large areas of complete washout. My glass is flat and the board is sitting tight and flat against the art. When the art and board are viewed during exposing everything looks normal. The washout areas occur in random places and sizes from board to board.
For the life of me I can't find anything different from how I have always done this. Any clues?
(There is some residual water on this board. Very noticeable on the left. Sorry, I didn't dry it well before taking the picture.)
