What are Plated Half-Holes/Castellated Holes?

Plated half holes or castellated holes are holes made off the edge of the boards which are then plated with copper using a specialized process. The plated edges are useful in producing mini PCB modules, much like Seeed's own WiFi modules, which are soldered onto a larger board in a similar way to ICs. Seeed Fusion uses a high quality bespoke plating process to plate half holes, we do not just cut the holes out. This results in cleaner, smoother and stronger edges and no sharp burrs or deformation.

Plated half holes are available in both standard and Advanced PCB services. For the standard PCB service, the minimum diameter of castellated holes is 0.5mm. If you need smaller castellated holes (as low as 0.35mm), please use the Advanced PCB service. When "Yes" is selected f
or this option, the half cut holes on the edges of the board will be plated with copper.  


If "No" is selected, half holes will not be plated with copper.



How to indicate castellated holes on your design?

Add a via or plated hole directly on the outline of the boards where the plated half hole is required. Ensure that half of the via is on the board and half is on the outside of the outline.  

Due to the nature of the plating process, the plated edges must be on an outer edge of the panel. Please take this into consideration when panelizing your designs. For example, if a board has plated half holes on both left and right edges, then the boards can only be panelized on the non-plated edges (top and bottom). If a rectangular board has plated edges on all four sides then it cannot be panelized.

If there appears to be plated half holes in your design, but the option for castellated holes is not selected, we may contact you directly to confirm whether castellated holes are required.

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