What must we bear in mind when its time to generate the documentation to manufacture a pcb?
When generating files to manufacture a printed circuit board we need to bear in mind some observations:
1. With the help of the CAD software all the needed layers have to be generated (soldermask, external layers, drilling, solder paste, etc.). We should not leave to the manufacturer the accomplishment of any of the layers. This will decrease the margin of error between the circuit we want and the manufactured circuit.
2. All files must ideally be made with the same measurement systems (millimetres, inches, tenths of inch) and place all layers in the same working position. The most usual one is to see the printed circuit board from the component side (top layer).
3. The output format of the different layers, if possible, should be done with Gerber 274x and the drilling one in an ASCII code with no extended characters (ACII NONE).
4. The Gerber files output resolution for the different layers, is advisable to be done in a 5 whole number and 5 tenths format. This format will assure a correct resolution when the Gerber format files have to be translated to the manufacturer’s format.
5. The drilling or Excellon file, is advisable to be done at least in a hundredth of millimetre resolution and enclose a drilling report were the number of holes and their plating choice can be seen
6. It is preferable to enclose a file the kind of “read-me. txt”, to explain any extra operations to bear in mind at the moment of. manufacturing the printed circuit board.
7. To make work easier and protect different files, it is preferable to create a compressed file with all that’s needed to make the printed circuit board.