How to Define Board Outline in PCB Design: Step-by-Step Guide

To define the board outline in a PCB, draw a closed shape on the Mechanical Layer or Edge.Cuts Layer that represents the physical edges of the board. This outline guides manufacturing and ensures the PCB is cut to the correct size and shape.

Syntax

In PCB design software, the board outline is defined by drawing a closed polygon or line on a specific layer reserved for board edges.

• Edge.Cuts Layer: The standard layer for board outlines in many tools like KiCad.
• Mechanical Layer: Sometimes used for custom outlines or additional mechanical details.
• Closed Shape: The outline must be a continuous, closed loop without gaps.

pseudo

DrawPolygon(layer="Edge.Cuts", points=[(x1,y1), (x2,y2), ..., (x1,y1)])

Example

This example shows how to define a rectangular board outline in KiCad by drawing on the Edge.Cuts layer.

steps

1. Open PCB Editor.<br>2. Select the Edge.Cuts layer.<br>3. Use the 'Add Graphic Line' tool.<br>4. Draw four lines connecting points:<br>   (0,0) to (100,0),<br>   (100,0) to (100,80),<br>   (100,80) to (0,80),<br>   (0,80) to (0,0).<br>5. Ensure lines form a closed rectangle.<br>6. Save the design.

Output

A rectangular board outline of 100mm by 80mm appears on the Edge.Cuts layer, defining the PCB shape.

Common Pitfalls

Common mistakes when defining board outlines include:

• Not closing the outline shape, causing manufacturing errors.
• Drawing on the wrong layer, so the outline is ignored.
• Overlapping or crossing lines that confuse the cutting process.
• Using non-standard units or coordinates that mismatch the design grid.

Always verify the outline is a single closed loop on the correct layer before sending to fabrication.

pseudo

Wrong: Draw lines on Copper layer instead of Edge.Cuts.
Right: Draw lines on Edge.Cuts layer only.

Quick Reference

Board Outline Quick Tips:

• Use Edge.Cuts layer for outlines.
• Draw a closed polygon with no gaps.
• Check units and grid settings before drawing.
• Keep outline simple and clear for manufacturing.
• Verify outline visibility in Gerber files.

Key Takeaways

Always draw the board outline as a closed shape on the Edge.Cuts layer.

Ensure no gaps or overlaps exist in the outline to avoid manufacturing issues.

Use correct units and grid settings matching your PCB design software.

Verify the outline appears correctly in output files before fabrication.

Avoid drawing outlines on copper or other electrical layers.