I am playing with our new CNC to mill PCB using a LPKF Universal Cutter. I used FlatCAM to generate g-code from the gerber files.

I encounter some issues with the routing. As shown below, some small copper shavings remain attached.

Is there any solution/strategy to eliminate them?

enter image description here enter image description here enter image description here enter image description here enter image description here

  • 2
    \$\begingroup\$ I think you might have to fix this in layout, simply don’t ever leave features that fine. Many pcb processes have limitations of this nature. \$\endgroup\$
    – Bryan
    Nov 28, 2022 at 17:26
  • \$\begingroup\$ BTW why use thin tracks when you can use thick ones? as much as I can see, you can easily use about 3 times thicker tracks and bigger holes/vias. \$\endgroup\$ Nov 28, 2022 at 18:02

1 Answer 1


It's a layout issue. There is a "no-go" clearance zone between the features for this manufacturing process. Either they must be closer or farther away. There used to be glass fiber cleanout brushes with short bristles for cleaning that sort of stuff from manually cut stripboards, but that was 30+ years ago. A blast of crushed peanut shells may also be enough to clean it out.

Any good planar mill CAM program will have a design rule check for minimum feature size, and should be able to remove such slivers automatically. Worth checking into it.

A quick workaround is to increase the pass overlap.

  • \$\begingroup\$ Circuitcam is one I've used in the past, kind of pricey though \$\endgroup\$
    – Voltage Spike
    Nov 28, 2022 at 18:35
  • \$\begingroup\$ It looks like the areas are meant to be connected according to the design, not disconnected \$\endgroup\$
    – user253751
    Nov 28, 2022 at 18:50
  • \$\begingroup\$ Glass fibre brushes still exist and can be readily bought anywhere that sells electronics tools. \$\endgroup\$
    – arne
    Nov 29, 2022 at 1:51

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.