Milling PCB workflow


Using Eagle,, InkScape and Fusion 360

Circuit and PCB layout

  • Make circuit and PCB layout in Autodesk Eagle (version 9.4.0)
  • File > Generate CAM data
  • Click OK. This will generate a zip archive with Gerber files (2D vector files used for PCB manufacturing).
  • Unzip the .zip file and open the GerberFiles folder.
  • Open to convert the desired Gerber files to SVG vector files.
  • Open the desired .SVG files in Inkscape.
  • use view > display mode > normal / outline to analyse the vector image.

    Seeing the image in the outline display mode (right), it becomes apparent that the traces have a width of zero mm.
  • edit > select all (ctrl + a)
  • object > ungroup (shift + ctrl + g)
  • the circles and squares are clones from hidden shapes. select one clone-object.
  • edit > select same > Object type (shift + alt + a)
  • file > clone > unlink clone (shift + alt + d). The clone objects have now been changed to circle and rectangle objects
  • edit > select all
  • path > objects to path
  • path > stroke to path
  • path > break apart
  • path > union
  • file > save as Choose SVG.

    Now you have a proper outline
  • insert the SVG file in fusion 360
  • set scale to 0,003779527597 (The dimensions set in Eagle are correct in InkScape, but with scale set to 1, 1,27mm in eagle becomes 336,02083mm in Fusion 360)
  • select contours, extrude and configure setup and trace operation for milling


When circles are actually 4 arcs they won't be selectable for a bore or drill operation.

  • Draw 2 construction lines between the 4 points of the bad circle.
  • Draw a circle to measure the diameter of the bad circle. Note the dimension and cancel the circle.
  • Delete the arc segments
  • Draw a the new circle with the measured diameter

These are proper circles.


Some arcs are composed of multiple smaller arcs.

  • Select all the segments by dragging the selection box from left to right. Only the line elements that are fully inside of the selection box are selected.
  • Delete them
  • Add a tangent arc

If traces come close together, the tool will lift, cutting a thinner trace. This allows to set a relatively deep trace over-all to accommodate flex in the PCB substrate.

  • Select the area in between traces and push it down a small amount. The depth doesn't matter. This creates a pocket we can use to select the engrave toolpath.

  • Add an engrave toolpath strategy and select the traces. You don't need to select the holes yet, but make sure to select a contour line around all the traces. That way Fusion knows at which side of the lines the tool need to be placed. I tested 0.3mm depth, but 0,2mm or shallower should work better.

    Here you can see the cut is made on the outside of the traces.

  • Put one of the PCB drills from the Hyrel kit in a 1/8“ (3.175mm) collet.
  • No need to ad these to the tool list in Fusion. Simulate them with a 1mm flat endmill.
  • Take the CAM profile “PCB-Drill” from CAM Templates > PCB. This plunges the drill straight down. As it does not helix, the hole is the same diameter as the drill.
  • isel_icv4030/milling_pcb_s.txt
  • Last modified: 2021/06/22 08:07
  • by formlab