Need advice on cnc to pcb circuit job!

[HankMcSpank]

My question was actually to the OP who doesn't already have a CNC machine and doesn't have the skills yet. If his goal as set out in the first post is to produce a few PCBs, it will be less expensive and return better quality to use the manufacturer I linked to. £30 will land you a handful of PCBs delivered to your door.

On the other hand, if you are doing this as a hobby then a CNC machine will give you a lot of joy and be highly useful! Alfons37 what is your ultimate goal?

The reason I used to us a CNC machine to make pcbs was for ultra fast prototyping. I can finish a circuit in eagle & have my board within the hour (vs weeks if using the cheapest chinese fab houses) ...as soon as you have the board, you can start debugging & revision II comes along .....the revision II board can be with me within the hour...rinse repeat.

In short if you are designing circuits, a CNC machine can't be beat for rapid prototyping. Of course once you have your final design...off to the fab house it goes.

FWIW, my design path...

Design board Eagle, then export tracks as gerber & excellon files, then import the gerber/eccellon to do the associated CAM work in Cambam...before finally using CNC-USB to mill the board (CNC-USB has features which are fantastic for pcb milling)

My top tip...find a local signmaker ....checkout their skip...there'll be loads of waste acrylic in there...it's perfectly flat & perfect for use as spoiler.

Even better than ensuring your board is flat ...use probing (which adjusts the Z plane cut depth in sympathy with the boards irregularities (a built in feature with CNC-USB .... https://www.youtube.com/watch?v=0jGY92S8bxM). This method means you don't even need spoiler...my pcb board was always clamped 8mm above my cncmachine's bed...I used tabs to keep the board in place & then just snipped the tabs out at the end.

For double side boards, I used index pins, but again CNC-USB has a feature called 'transformation' which in theory allows you to flip a board over without index pins, the idea is to use a Z mounted webcam to jog to some known coords & then it'll work out the adjustments to ensure your top surface & lower surface are perfectly aligned (this video sort of explains it - https://www.youtube.com/watch?v=JJnenOsbCzU )