When building components from Gerber files, understanding the relationship between component polarity and orientation is important.
Note: In this post you can think of Component Orientation and Rotation as the same.
1. Determine which Components have Polarity Requirements.
Non-Polar Components: Components that do not have positive/negative pins; essentially the component pins are not required to be in a specific order. These are the easiest components to build from gerber files, because their rotation is typically not important. There are many types of Non-Polarized components such as:
- Capacitors (Monolithic and Ceramic)
- Oscillators (crystal 2-pin)
- Resonators (crystal 2-pin)
- and more...
Polar Components: Components need to be placed with the correct direction and orientation. It's important after building polar components from Gerber files, to go back and verify the rotations.
2. Use the Gerber Silkscreen layer to help determine Component Orientation.
Fortunately most Gerber silkscreen layers give many clues regarding the correct rotations for polar components. Here's a good article written by Sierra Circuits Inc (the sample image below is from that article) >>
IMPORTANT: Make sure to ALWAYS verify rotations for polarized components (generated from Gerber files) to ensure correctness before exporting to Centroid File, ODB++, etc.
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