![\"PCB](\"https:\/\/www.rigiflex.com\/blog\/wp-content\/uploads\/2026\/11\/PCB-Castellation.png\")
<\/a><\/p>\nUnderstanding how castellated holes work in PCB design helps engineers make informed decisions about hole dimensions, copper plating, board layout, and assembly requirements. This PCB castellation guide explains the manufacturing process, essential design considerations, common applications, advantages, and limitations.<\/p>\n
What Is PCB Castellation?<\/strong><\/h2>\nPCB castellation is a manufacturing technique in which plated holes are positioned along a PCB edge and cut through during board profiling to expose the plated copper barrel. These openings, known as castellated holes or plated half-holes, form solderable contacts for mounting one PCB onto another.<\/p>\n
Unlike a conventional plated through-hole, which is enclosed by the surrounding board material, a castellated hole is partially exposed along the board edge, allowing its plating to be soldered to matching pads on a carrier board.<\/p>\n
How Does PCB Castellation Work?<\/strong><\/h2>\nConsider a small wireless module designed to connect to a larger motherboard. The module has a row of plated holes along its edge. During fabrication, the board outline intersects these holes, exposing part of their plated copper barrels. During assembly, solder joins the exposed castellations to corresponding surface-mount pads on the motherboard.<\/p>\n
A simplified comparison is:<\/p>\n
\n- Standard plated through-hole:<\/strong> A plated hole enclosed by Flex PCB material<\/a>.<\/li>\n
- PCB castellated hole:<\/strong> A plated hole intersected by the board edge, leaving part of its plated barrel exposed.<\/li>\n
- Assembled connection:<\/strong> Solder joins the exposed plating to a matching pad on the carrier board.<\/li>\n<\/ul>\n
The exact geometry depends on the hole position relative to the board outline and the manufacturer’s fabrication process.<\/p>\n
How Are Castellated Holes Manufactured?<\/strong><\/h2>\nProducing reliable PCB castellated holes requires coordinated fabrication steps, such as.<\/p>\n
\n- Hole Drilling:<\/strong> The manufacturer drills holes at specified locations along the intended castellated edge. Hole diameter, spacing, and position must follow the fabrication data and account for the manufacturer’s process capabilities.<\/li>\n
- Copper Plating:<\/strong> The drilled holes are metallized to create conductive barrels. Copper plating establishes electrical continuity through the holes and provides the conductive surface needed for soldering. The fabrication data must identify these as plated holes, not non-plated holes.<\/li>\n
- Board Profiling and Edge Cutting:<\/strong> The board outline is routed through the plated holes to expose their copper barrels, creating the characteristic half-hole geometry. Accurate routing helps preserve the remaining plating and achieve the specified edge dimensions.<\/li>\n
- Surface Finishing:<\/strong> The exposed castellated contacts receive the specified surface finish as part of the PCB finishing process. The finish should be compatible with the intended soldering method, storage conditions, and assembly requirements.<\/li>\n
- Final Inspection:<\/strong> The finished board is inspected for hole position, plating integrity, edge quality, and dimensional accuracy. Visual inspection and appropriate electrical tests help identify defects that could compromise the solder connection or electrical performance.<\/li>\n<\/ol>\n
PCB Castellation Design Considerations<\/strong><\/h2>\nSuccessful castellated-hole design begins with the electrical and mechanical requirements of the module and its carrier board. Early coordination with the PCB manufacturer helps avoid fabrication changes and assembly problems.<\/p>\n
\n- Hole Size and Pitch:<\/strong> Hole diameter and pitch affect the available soldering area and spacing between adjacent connections. Very small holes or closely spaced castellations can increase manufacturing difficulty and the risk of plating defects or solder bridging. Select dimensions that meet the electrical requirements and the manufacturer’s process capabilities.<\/li>\n
- Pad Dimensions:<\/strong> Copper land geometry must provide a suitable solderable area around each plated hole. The design should account for the hole diameter and board outline to help preserve plating integrity after edge profiling and support reliable solder-joint formation.<\/li>\n
- Board Thickness:<\/strong> Board thickness affects the edge geometry of the castellated contacts and the physical relationship between the module and carrier board. Choose a PCB thickness<\/a> that suits the mounting arrangement, required solder-joint geometry, and available space.<\/li>\n
- Edge Clearance and Hole Spacing:<\/strong> Castellated holes must be positioned accurately relative to the board outline. Their placement determines how much of each plated hole remains after profiling. Adequate spacing between adjacent holes helps maintain copper integrity and reduces the risk of solder bridging.<\/li>\n
- Plating and Surface Finish:<\/strong> Reliable castellations require sound copper plating and a surface finish compatible with the assembly process. Confirm plating requirements, solder mask openings, and available surface finishes with the manufacturer before fabrication.<\/li>\n
- Manufacturing Tolerances:<\/strong> Drilling and routing tolerances affect the final geometry of each castellated opening. Design files should clearly define plated-hole locations and the board outline. There is no universal minimum hole diameter or pitch for every castellated PCB; acceptable dimensions depend on the manufacturer’s process capabilities and the specific board design.<\/li>\n<\/ul>\n
Applications of PCB Castellations<\/strong><\/h2>\nPCB castellation is useful when a compact circuit module needs to connect directly to a larger board.<\/p>\n
\n- Module-to-Carrier Board Connections:<\/strong> Castellations allow small functional modules to be soldered directly onto a host PCB without a separate pin header or connector.<\/li>\n
- Wireless and IoT Modules:<\/strong> Wi-Fi, Bluetooth, and other wireless modules can use castellated edges for compact integration into electronic products.<\/li>\n
- RF and Communication Modules:<\/strong> Castellated connections support the integration of selected radio-frequency and communication circuits, provided the PCB layout design<\/a>, grounding, and signal paths meet the electrical requirements.<\/li>\n
- Compact Electronic Devices:<\/strong> Products with limited space can benefit from reduced connector height and fewer separate interconnect components, depending on the assembly design.<\/li>\n
- Prototyping and Embedded Systems:<\/strong> Castellated modules allow developers to integrate predesigned circuits into custom carrier boards for testing, product development, and embedded applications.<\/li>\n<\/ul>\n
Advantages and Limitations of PCB Castellation<\/strong><\/h2>\nPCB castellation offers several benefits for compact electronic assemblies, particularly in module integration and board-to-board connectivity.<\/p>\n
\n- Compact Board-to-Board Connections<\/strong>: Castellated holes provide solderable edge connections without requiring a separate connector in many applications.<\/li>\n
- Simplified Module Integration<\/strong>: Preassembled modules can be mounted onto a carrier PCB, helping streamline product integration and assembly.<\/li>\n
- Surface-Mount Compatibility<\/strong>: Castellated edges can be soldered to matching surface-mount pads, making them suitable for compatible automated assembly processes.<\/li>\n
- Space Efficiency<\/strong>: Direct soldering can reduce connector height and save space in compact electronic designs.<\/li>\n<\/ul>\n
Limitations<\/strong><\/h3>\nDespite these benefits, PCB castellation requires careful design and manufacturing control to maintain plating integrity and achieve reliable solder joints.<\/p>\n
\n- Manufacturing Precision: <\/strong>Drilling, copper plating, and edge routing must be controlled to produce consistent castellations.<\/li>\n
- Plating Integrity: <\/strong>Poorly controlled routing can damage exposed copper or compromise the plated barrel, affecting solderability and connection reliability.<\/li>\n
- Design Constraints: <\/strong>Hole size, spacing, pad geometry, and board-edge positioning must comply with manufacturing limits.<\/li>\n
- Inspection and Assembly Requirements: <\/strong>Castellated connections require suitable inspection and assembly controls to verify solder-joint quality and prevent bridging or incomplete connections.<\/li>\n<\/ul>\n
Request a Quote from Rigiflex Technology, Inc.<\/strong><\/h3>\nPlanning a PCB project that requires castellated holes?<\/p>\n
Rigiflex Technology<\/a>, Inc. offers rigid, flexible, and rigid-flex PCB manufacturing<\/a>, with edge castellation capabilities. Share your fabrication data, design requirements, and production needs with our team to discuss your project.<\/p>\nFrequently Asked Questions<\/strong><\/h3>\nWhat is the difference between a castellated hole and a standard PCB via?<\/strong><\/h4>\nA standard via is typically enclosed within the PCB, while a castellated hole is cut through the board edge to expose part of its plated copper barrel. Castellations commonly provide solderable board-to-board connections.<\/p>\n
Are PCB castellated holes suitable for surface-mount assembly?<\/strong><\/h4>\nYes. Castellated holes can be soldered to matching surface-mount pads on a carrier board. Their geometry and soldering process must be appropriate for the assembly design.<\/p>\n
Can castellated holes be used on multilayer PCBs?<\/strong><\/h4>\nYes. Castellations can be incorporated into multilayer boards when the required copper connections, hole plating, edge geometry, and manufacturing tolerances are supported by the fabrication process.<\/p>\n
What should I provide when requesting a castellated PCB quote?<\/strong><\/h4>\nProvide the PCB fabrication files, drill data, board outline, layer stack-up, hole dimensions, copper and surface-finish requirements, and assembly details where available. Identify the castellated edges clearly so the manufacturer can review feasibility and quotation requirements.<\/p>\n
Do castellated holes increase PCB manufacturing costs?<\/strong><\/h4>\nThey can. Castellations require additional attention to hole placement, plating, edge routing, and inspection. The cost impact depends on board geometry, manufacturing complexity, order quantity, and the supplier’s process.<\/p>\n","protected":false},"excerpt":{"rendered":"
Advanced electronic products often require compact, reliable connections between circuit boards without bulky connectors or additional wiring. PCB castellation provides a practical solution by allowing one printed circuit board (PCB) to be soldered directly onto another. This technique is widely used in compact electronic modules, wireless devices, and embedded systems where space and assembly efficiency<\/p>\n
Consider a small wireless module designed to connect to a larger motherboard. The module has a row of plated holes along its edge. During fabrication, the board outline intersects these holes, exposing part of their plated copper barrels. During assembly, solder joins the exposed castellations to corresponding surface-mount pads on the motherboard.<\/p>\n
A simplified comparison is:<\/p>\n
- \n
- Standard plated through-hole:<\/strong> A plated hole enclosed by Flex PCB material<\/a>.<\/li>\n
- PCB castellated hole:<\/strong> A plated hole intersected by the board edge, leaving part of its plated barrel exposed.<\/li>\n
- Assembled connection:<\/strong> Solder joins the exposed plating to a matching pad on the carrier board.<\/li>\n<\/ul>\n
The exact geometry depends on the hole position relative to the board outline and the manufacturer’s fabrication process.<\/p>\n
How Are Castellated Holes Manufactured?<\/strong><\/h2>\n
Producing reliable PCB castellated holes requires coordinated fabrication steps, such as.<\/p>\n
- \n
- Hole Drilling:<\/strong> The manufacturer drills holes at specified locations along the intended castellated edge. Hole diameter, spacing, and position must follow the fabrication data and account for the manufacturer’s process capabilities.<\/li>\n
- Copper Plating:<\/strong> The drilled holes are metallized to create conductive barrels. Copper plating establishes electrical continuity through the holes and provides the conductive surface needed for soldering. The fabrication data must identify these as plated holes, not non-plated holes.<\/li>\n
- Board Profiling and Edge Cutting:<\/strong> The board outline is routed through the plated holes to expose their copper barrels, creating the characteristic half-hole geometry. Accurate routing helps preserve the remaining plating and achieve the specified edge dimensions.<\/li>\n
- Surface Finishing:<\/strong> The exposed castellated contacts receive the specified surface finish as part of the PCB finishing process. The finish should be compatible with the intended soldering method, storage conditions, and assembly requirements.<\/li>\n
- Final Inspection:<\/strong> The finished board is inspected for hole position, plating integrity, edge quality, and dimensional accuracy. Visual inspection and appropriate electrical tests help identify defects that could compromise the solder connection or electrical performance.<\/li>\n<\/ol>\n
PCB Castellation Design Considerations<\/strong><\/h2>\n
Successful castellated-hole design begins with the electrical and mechanical requirements of the module and its carrier board. Early coordination with the PCB manufacturer helps avoid fabrication changes and assembly problems.<\/p>\n
- \n
- Hole Size and Pitch:<\/strong> Hole diameter and pitch affect the available soldering area and spacing between adjacent connections. Very small holes or closely spaced castellations can increase manufacturing difficulty and the risk of plating defects or solder bridging. Select dimensions that meet the electrical requirements and the manufacturer’s process capabilities.<\/li>\n
- Pad Dimensions:<\/strong> Copper land geometry must provide a suitable solderable area around each plated hole. The design should account for the hole diameter and board outline to help preserve plating integrity after edge profiling and support reliable solder-joint formation.<\/li>\n
- Board Thickness:<\/strong> Board thickness affects the edge geometry of the castellated contacts and the physical relationship between the module and carrier board. Choose a PCB thickness<\/a> that suits the mounting arrangement, required solder-joint geometry, and available space.<\/li>\n
- Edge Clearance and Hole Spacing:<\/strong> Castellated holes must be positioned accurately relative to the board outline. Their placement determines how much of each plated hole remains after profiling. Adequate spacing between adjacent holes helps maintain copper integrity and reduces the risk of solder bridging.<\/li>\n
- Plating and Surface Finish:<\/strong> Reliable castellations require sound copper plating and a surface finish compatible with the assembly process. Confirm plating requirements, solder mask openings, and available surface finishes with the manufacturer before fabrication.<\/li>\n
- Manufacturing Tolerances:<\/strong> Drilling and routing tolerances affect the final geometry of each castellated opening. Design files should clearly define plated-hole locations and the board outline. There is no universal minimum hole diameter or pitch for every castellated PCB; acceptable dimensions depend on the manufacturer’s process capabilities and the specific board design.<\/li>\n<\/ul>\n
Applications of PCB Castellations<\/strong><\/h2>\n
PCB castellation is useful when a compact circuit module needs to connect directly to a larger board.<\/p>\n
- \n
- Module-to-Carrier Board Connections:<\/strong> Castellations allow small functional modules to be soldered directly onto a host PCB without a separate pin header or connector.<\/li>\n
- Wireless and IoT Modules:<\/strong> Wi-Fi, Bluetooth, and other wireless modules can use castellated edges for compact integration into electronic products.<\/li>\n
- RF and Communication Modules:<\/strong> Castellated connections support the integration of selected radio-frequency and communication circuits, provided the PCB layout design<\/a>, grounding, and signal paths meet the electrical requirements.<\/li>\n
- Compact Electronic Devices:<\/strong> Products with limited space can benefit from reduced connector height and fewer separate interconnect components, depending on the assembly design.<\/li>\n
- Prototyping and Embedded Systems:<\/strong> Castellated modules allow developers to integrate predesigned circuits into custom carrier boards for testing, product development, and embedded applications.<\/li>\n<\/ul>\n
Advantages and Limitations of PCB Castellation<\/strong><\/h2>\n
PCB castellation offers several benefits for compact electronic assemblies, particularly in module integration and board-to-board connectivity.<\/p>\n
- \n
- Compact Board-to-Board Connections<\/strong>: Castellated holes provide solderable edge connections without requiring a separate connector in many applications.<\/li>\n
- Simplified Module Integration<\/strong>: Preassembled modules can be mounted onto a carrier PCB, helping streamline product integration and assembly.<\/li>\n
- Surface-Mount Compatibility<\/strong>: Castellated edges can be soldered to matching surface-mount pads, making them suitable for compatible automated assembly processes.<\/li>\n
- Space Efficiency<\/strong>: Direct soldering can reduce connector height and save space in compact electronic designs.<\/li>\n<\/ul>\n
Limitations<\/strong><\/h3>\n
Despite these benefits, PCB castellation requires careful design and manufacturing control to maintain plating integrity and achieve reliable solder joints.<\/p>\n
- \n
- Manufacturing Precision: <\/strong>Drilling, copper plating, and edge routing must be controlled to produce consistent castellations.<\/li>\n
- Plating Integrity: <\/strong>Poorly controlled routing can damage exposed copper or compromise the plated barrel, affecting solderability and connection reliability.<\/li>\n
- Design Constraints: <\/strong>Hole size, spacing, pad geometry, and board-edge positioning must comply with manufacturing limits.<\/li>\n
- Inspection and Assembly Requirements: <\/strong>Castellated connections require suitable inspection and assembly controls to verify solder-joint quality and prevent bridging or incomplete connections.<\/li>\n<\/ul>\n
Request a Quote from Rigiflex Technology, Inc.<\/strong><\/h3>\n
Planning a PCB project that requires castellated holes?<\/p>\n
Rigiflex Technology<\/a>, Inc. offers rigid, flexible, and rigid-flex PCB manufacturing<\/a>, with edge castellation capabilities. Share your fabrication data, design requirements, and production needs with our team to discuss your project.<\/p>\n
Frequently Asked Questions<\/strong><\/h3>\n
What is the difference between a castellated hole and a standard PCB via?<\/strong><\/h4>\n
A standard via is typically enclosed within the PCB, while a castellated hole is cut through the board edge to expose part of its plated copper barrel. Castellations commonly provide solderable board-to-board connections.<\/p>\n
Are PCB castellated holes suitable for surface-mount assembly?<\/strong><\/h4>\n
Yes. Castellated holes can be soldered to matching surface-mount pads on a carrier board. Their geometry and soldering process must be appropriate for the assembly design.<\/p>\n
Can castellated holes be used on multilayer PCBs?<\/strong><\/h4>\n
Yes. Castellations can be incorporated into multilayer boards when the required copper connections, hole plating, edge geometry, and manufacturing tolerances are supported by the fabrication process.<\/p>\n
What should I provide when requesting a castellated PCB quote?<\/strong><\/h4>\n
Provide the PCB fabrication files, drill data, board outline, layer stack-up, hole dimensions, copper and surface-finish requirements, and assembly details where available. Identify the castellated edges clearly so the manufacturer can review feasibility and quotation requirements.<\/p>\n
Do castellated holes increase PCB manufacturing costs?<\/strong><\/h4>\n
They can. Castellations require additional attention to hole placement, plating, edge routing, and inspection. The cost impact depends on board geometry, manufacturing complexity, order quantity, and the supplier’s process.<\/p>\n","protected":false},"excerpt":{"rendered":"
Advanced electronic products often require compact, reliable connections between circuit boards without bulky connectors or additional wiring. PCB castellation provides a practical solution by allowing one printed circuit board (PCB) to be soldered directly onto another. This technique is widely used in compact electronic modules, wireless devices, and embedded systems where space and assembly efficiency<\/p>\n
- Plating Integrity: <\/strong>Poorly controlled routing can damage exposed copper or compromise the plated barrel, affecting solderability and connection reliability.<\/li>\n
- Simplified Module Integration<\/strong>: Preassembled modules can be mounted onto a carrier PCB, helping streamline product integration and assembly.<\/li>\n
- Wireless and IoT Modules:<\/strong> Wi-Fi, Bluetooth, and other wireless modules can use castellated edges for compact integration into electronic products.<\/li>\n
- Pad Dimensions:<\/strong> Copper land geometry must provide a suitable solderable area around each plated hole. The design should account for the hole diameter and board outline to help preserve plating integrity after edge profiling and support reliable solder-joint formation.<\/li>\n
- Copper Plating:<\/strong> The drilled holes are metallized to create conductive barrels. Copper plating establishes electrical continuity through the holes and provides the conductive surface needed for soldering. The fabrication data must identify these as plated holes, not non-plated holes.<\/li>\n
- PCB castellated hole:<\/strong> A plated hole intersected by the board edge, leaving part of its plated barrel exposed.<\/li>\n