Don’t get me wrong. I LOVE this process. I’m just less that thrilled with the quality of traces, so from here on, will be testing etching instead. However, I told Chugs I would document this process, so I am. Perhaps later, I’ll try a 45 degree spade bit. I’ve read they are “more forgiving.” It doesn’t take much movement for the boards to become ineffective. Just .001″ can ruin a trace.
Here are my steps to milling PCBs. The images in the gallery are in order. It’s just too much time to link each file independently, so here’s the gallery:
1. The board is designed in Eagle. PCB-GCode is run to create the machining code. Also, credit where credit is due. Since this was my first major electronics project, I went in search of schematics to learn from. This board is based on this wonderful schematic: http://www.dcordes.freeuk.com/analyser.htm. Thank you. I’ve learned so much! However, I did add some stuff ;)
2. The PCB fixture is cleaned and board removed from box.
3. Router is zeroed to fixture.
4. PCB taped to fixture for index hole drilling for flipping in the registry system. The fixture has drill holes at zero, every inch (-6 to 0 to +6). This ensure the board is level to routing when flipped. Clips from paper clips act as my pins.
5. The bit used for drilling index holes is slightly smaller than the paperclip diameter, so the holes are enlarged with the paper clip.
6. Board is super glued to the fixture to hold it as flat as possible. This particular PCB was unusually warpy.
7. Y-axis is moved +.2 inches away from the index holes. This gives plenty of room for the 1/8″ bit to cutout the board.
8. A bit index hole is drilled at the new x0,y0 point. This ensures you don’t loose steps and your bits are where they should be during changes and milling.
9. Vias are drilled. There are several bit size changes. Mach3 is set to stop for tool changes. Tedious, but quite enjoyable, I think.
10. Top engraving of traces is now done.
11. Acetone and a razor blade are used to remove the board. The board and fixture are cleaned with the same tools, ready to be flipped.
12. Other side of board is glued to the fixture.
13. Tired of watching etching now, so time to take some photos of the lakes in front of the house. Will this raise the property value? Man, I need about $4000 worth of gravel. It’s getting pretty muddy here :)
14. Bottom engraving continues.
15. The board’s dimensions are milled.
16. Again, acetone and a razor blade remove the PCB and the newly built board.
17. Clean up the board and solder parts.
A bit of video on the etching process: