Creating Quick and Easy Rounded Corners In Autodesk Eagle PCB Design

Been designing and building PCB(s) for projects I’ve been working on. I found that while the perfect right angle corners of a PCB board had a certain cache… I really liked the organic feel of rounded corner PCB(s).

Youtube Video Demonstrating How To Create Rounded Corner PCB(s) in Eagle PCB Design

Steps For Creating a Rounded corner Outline for a 50x50mm Board In Eagle PCB Design

The fastest way to do this is with the ARC tool in Eagle. However, in order for it to work, you need the end points of the ARC to match with another line/endpoint sufficiently closely for Eagle to recognize that they should be joined and for new segments to be created.

The fastest way to do this is ensure that your endpoints all end up on the same aligned grid by using Eagle’s Grid Size feature.

Eagle PCB Design UI displaying a PCB outline with rounded corners and M3 drill holes.

Steps For Creating a Rounded corner Outline for a 50x50mm Board In Eagle PCB Design (TLDR; Version)

  • Create a new Eagle PCB Board.
  • Select and delete all lines/objects on the board design. Start with a clean slate.
  • Set the Grid size to 50 mm. Note, by default, Eagle PCB uses “mils” or 1/1000th of an Inch.
  • Also, turn on grid lines.
  • Select the LINE tool and make sure that you are drawing on the DIMENSION layer with a LINE WIDTH of 0.
  • You can now click near (0,0), then going up, at (0,50), then (50,50), (50,0), and finally back to (0,0). Click at that point again to end the line drawing or just hit ESC.
  • You now have a 50x50mm boundary where you did not have one before.
  • Go to the the Grid Size again and change the value from 50mm down to 5mm.
  • Select the HOLE tool and set the diameter to 3.2 (this will work great with an M3 bolt)
  • Click on the grid intersections inside of each corner. This will place a hole with a center inset of 5mm from the top, bottom, and sides.
  • Now, click on the ARC tool. Depending on whether the tool is clockwise or counterclockwise, where you start will be reversed. I’m writing for clockwise direction.
  • For the upper left hole, click on the left edge at the 5mm down from top, then move to the right creating a circle that will be inside of the corner, touching the external wall. Have the ARC end at the top.
  • Rinse and repeat for each corner, starting from their respective sides and finishing on the neighboring side.
  • Go back and delete the hard corner segments.
  • You now have a rounded corner PCB board outline!

Edit/Update: Another video! With Audio!

So I took a bit of time and created another version of the video. This time, I go with 100x100mm and instead of the custom mount hole I had created, I use the hole/drill option.

Check it out!

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