Meaning
Printed circuit board assembly methods secure electronic components to a board by placing their wire leads through pre-drilled holes and soldering them to copper pads on the opposite side. While through hole insertion is often replaced by surface-mount technology for tiny components, it remains standard for heavy connectors and power supply modules. This process establishes exceptionally strong mechanical connections.
The method is restricted to through-hole boards and is not used for components mounted directly to surface pads.
Mechanical Assembly
Robotic insertion heads bend and feed the component leads into the board. During through hole insertion, automation equipment cuts the excess lead and crimps the wire on the underside.
Electrical Integrity
Industrial assemblies subjected to harsh vibrations or high thermal stress depend on these robust mechanical solder joints. If through hole insertion is executed correctly, the solder rises through the barrel of the hole to form a complete fillet on both sides of the board. This structural volume prevents cracking under mechanical loads.
The resulting joint is highly reliable for high-current terminal blocks and heavy radio-frequency antenna connectors.
Process Limitation
High-density circuit boards with multiple signal layers must allocate limited routing channels to accommodate these large through-board drilled holes. Designing for through hole insertion increases the size of the board and prevents components from being mounted on the opposite side of the same board area. The increased trace routing constraints limit the use of this method to large power-handling circuits or rugged physical connectors.
Production engineers always select surface-mount devices for compact wireless modules to maximize board density.
