Need advice on cnc to pcb circuit job!

[davegrennan]

alfons, I just thought I'd return here and add a few pointers that I've picked up while taking my first steps into milling PCBs. Hopefully these will save you a few ruined copper boards!
>
First level is everything, if your board is not EXACTLY perpendicular you cannot take the really shallow cuts that you would like. Either you will cut too deep in some parts or cut air in others. Set up a touch probe and use something like autoleveller software to level your gcode with your workpiece. It really did the business for me.
>
I found that MFD makes a particularly good spoilboard for pcbs. Use double sided tape to hold down the copper board. Using clamps just bends the board! A few strips of tape is strong enough to hold it secure and is easy to get off afterwards.
>
Use alignment pins for double sided boards. You just cannot line uop accurately enough just flipping the board by eye, even using marks on the spoilboard.
>
Keep in mind that as holes are not plated through you could (likely) have great difficulty in soldering some components, use smd where possible. If you are used to working with commercial grade boards with resist and solder mask etc, its easy to forget this and then realise you cannot actually complete your shiny new cnc made board (happened to me).
>
Lastly keep your designs modest and your tracks as fat as possible. Even using 0.1mm V bit, its very difficult to actually cut 0.1mm in copper, expect maybe 0.3mm. I'm sure with more experience it will be possible to get thinner cuts. And keep in mind that the extra cut width will come off your track, so it will be narrower than planned.
>
Hope some of this is helpful to you when you do get to finally mill some copper.