Castellated Holes PCB Guide
What are Castellated Holes on a PCB?
As electronic devices become more compact and multifunctional, the demand for efficient soldering processes has increased. Traditional round holes can lead to cold solder joints, affecting the electrical connection between the motherboard and daughterboard. To address this issue, plated half holes, known as castellated holes, are being widely adopted.
Castellated holes are specialized indentations on PCB edges that facilitate mounting one board on top of another. These semi-plated holes ensure proper alignment and soldering between boards, enhancing overall product functionality. Whether in Wi-Fi or Bluetooth modules, castellated holes enable direct board-to-board connections, streamlining assembly processes.
Through-Hole Technologyand Surface Mount technology are commonly used in PCB assembly, with board-to-board soldering being a prevalent practice. By incorporating castellated holes, PCBs can be securely linked to various modules, creating a thin yet robust system without bulky connectors.
PCB manufacturing process for castellation holes
The manufacturing process for plated half holes involves several key steps:
- Drilling
- Ensuring plated holes
- Performing panel plating
- Image transfer
- Pattern plating
- Striping
- Etching
- Solder masking
- Surface coating
- Implementing plated half holes
When stacking PCBs using plated half holes, it is essential to ensure not only a physical connection but also electrical contact between the boards for optimal performance.
Why Zero Spacing Between PCB Boards is Crucial
Having zero spacing between PCB boards is essential for successful soldering. Even a tiny space can disrupt the soldering process, leading to incomplete connections.
Benefits of Plated Half Holes in PCB Assembly
- Plated half holes are a cost-effective technique that transforms PCBs into surface-mountable sub-assemblies.
- These concave and plated holes on PCB edges enhance soldering connections and prevent moisture and dust accumulation between boards.
Exploring the Use of Castellated Holes
Castellated holes located on PCB edges replicate various circuit parts, allowing for easy mass production of sub-circuits that can be soldered onto main PCBs. Here are some applications:
- Acting as breakout boards for specific PCB areas.
- Facilitating pin layout customization for components.
- Enabling easy stacking of PCBs with castellated holes.
- Validating solder joint quality when combining PCBs.
- Creating integrated modules for further assembly processes.
- Commonly used in Wi-Fi modules and breakout boards.
- Facilitating wireless PCB-to-PCB links.
Designing Castellated Holes with Images
Castellated holes utilize a via process involving drilling and copper plating, with microvias being a miniature version suitable for high-quality PCB manufacturing. Various types of castellated holes include:
Half Holes
Holes with Smaller Cut-in-Half Holes
Holes with Smaller Lead-in-Holes for Post-Processing
Suggested Specifications for Castellated Holes
- Size: To ensure proper PCB mounting with castellated holes, opt for the largest size available.
- Diameter and Distance: For standard PCBs, use a minimum hole diameter of 0.6 mm. Advanced PCBs may require smaller diameters, with a minimum distance between holes of 0.55 mm.
- Surface Finish: Consider ENIG finish for optimal surface quality, or choose a finish based on the PCB’s intended application.
- Pad Design: Utilize the largest pads possible for better alignment and assembly of castellated PCBs.
When using castellated holes, aim to minimize the number of holes on the board to simplify alignment and assembly. Adjust the hole count based on your specific design requirements.
By adhering to these recommendations, your PCBs will fit together seamlessly, streamlining the assembly process.
Applications of Plated Half Holes
Castellated holes find widespread use in various industries, including:
- Telecommunication
- Computer applications
- Industrial control
- Power sector
- Automotive industry
- High-end consumer electronics
Call to Action
If you have any questions about utilizing castellated holes in your PCB projects, do not hesitate to reach out to us. Our team is here to provide assistance and guidance.
