Understanding Castellated Holes in PCBs
Castellated holes, also known as plated half-holes, are specialized features located at the edges of printed circuit boards (PCBs). These unique structures are formed by machining standard plated through-holes (PTH) and then partially cutting them, resulting in a “half-hole” appearance at the board’s edge. The purpose of castellated holes is to create a fortress-like structure that simplifies interconnections between PCBs.
One common application of castellated holes is in board-to-board connections and signal circuits. By allowing components to be soldered directly onto the PCB edge, this design eliminates the need for connectors, saving valuable space and streamlining assembly processes. For instance, Bluetooth or Wi-Fi modules featuring castellated holes can be seamlessly soldered onto the main board, ensuring a compact and tidy layout without the use of additional wiring.
Despite their benefits in terms of ease of assembly and space efficiency, castellated holes are considered a specialized technique within the PCB industry. Consequently, their production entails higher costs and longer lead times compared to conventional methods.
While the manufacturing process for castellated holes has matured over time, continuous efforts to refine production techniques, minimize defects such as scratches or irregularities, and enhance overall quality and efficiency are essential for staying competitive in the dynamic PCB market.
Castellated Hole Specifications at Wellcircuits
At Wellcircuits, castellated holes are incorporated along the PCB edges, extending beyond the board outline (excluding vias). Here are the diameter specifications for our manufacturing process:
- Minimum hole diameter: 0.5mm
- Remaining hole portion within the PCB: at least 0.25mm
- Spacing between adjacent castellated holes: no less than 0.55mm
For castellated holes positioned at right angles, a minimum hole diameter greater than 1.2mm is recommended to ensure structural integrity and facilitate soldering processes.
If you have inquiries regarding PCBs or PCBA services, don’t hesitate to reach out to us at Wellcircuits. Our team is dedicated to supporting your PCB and assembly requirements.
