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
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!
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…