Milling

To start etching (Isolation milling) PCB’s I had read that the secret to a perfect etch is to keep the copper clad board completely flat. I have seen it done several ways. These include :

  • Place it in a pocket of wood
  • Duct tape and secure the edges
  • Drill holes in the board and use pins
  • Clamps

For my first test I chose to use the pocket method. This way I could test the CNC to mill a perfect size pocket in some MDF. I made the pocket design in some software called “CamBam” which has a limited use trial. This software quite easy to use and I had a finished design made within 20 minutes. Having exported the design to Mach 3, my CNC got started.

It took about 20 minutes to mill 160x100mm at a depth of 0.4mm and about an hour and a half to get to the target depth. Looking back as it was MDF it could probably done it much faster by cutting deeper. MDF is quite soft and wouldn’t of been an issue… I think!

Pocket in MDF for PCB

PCB in MDF pocket

Anyway, the finished result was not quite what I was hoping for. As you can see the PCB rises out of the pocket. I can push it back in, but with vibration, it doesn’t sit still.

The actual cutting process and the design though was exactly what I expected, I wasn’t disappointed.

I have since bought some more copper clad board and they were .5mm smaller, which meant it would have moved even more!

Next time I will try the duct tape route…

  • http://Learntosolder.org Randy

    Also, I see you’re using CamBam. I have had much better luck with CamBam than PCB-GCode. Eagle to Gerber. Gerber to CamBam. This lets me panel the board the way I want. For drilling, there’s an Excellon plugin for CamBam that works well.

    • http://makerflux.com/members/myfrog/ Steven Pearson

      This sounds like a great tip, thanks! I am traveling away with work, but I will give this a go later in the week and post how I get on. PCB-Gcode does seem to produce a very strange result, at least for me anyway, it leaves too much isolation on one side than the other… Cheers!!!

  • Jouko Lehtomäki

    Steven, one year has now elapsed since you got that machine. Have you used it a lot and have you been satisfied with it? Has any of its components failed in use?

    • http://geekboy.it/ Steven Pearson

      Hi, I will do an article in the next couple of weeks on it. I think it could be good to share the year. However to answer your question, the only real issue was the cables. These needed replacing after about 20 hours of use.