Large-size splicing technology enables the fabrication of rigid printed boards larger than standard panel sizes (typically >600×800 mm), used in applications like industrial control panels, automotive dashboards, and large displays. This technology combines multiple smaller rigid PCBs into a single functional unit, overcoming manufacturing limitations of large-format substrates.

The splicing method depends on mechanical or electrical requirements. Mechanical splicing uses connectors (e.g., board-to-board headers) or mounting brackets to join PCBs, ensuring alignment with ±0.1 mm precision. This is ideal for non-critical electrical paths, allowing easy replacement of damaged sections. Electrical splicing employs solder bridges, flexible copper strips, or conductive adhesives to create continuous electrical connections between boards, critical for high-current or high-frequency signals.

Design considerations include signal integrity—spliced connections must minimize impedance discontinuities. For high-speed signals (>1 Gbps), differential pairs are routed across splices with matched lengths (±0.5 mm) and controlled impedance (50 or 100 Ω). Thermal management is crucial: splice points are spaced ≥20 mm apart, and heat-dissipating pads are added to prevent hotspots, especially in power electronics.

Manufacturing involves alignment fixtures to position PCBs during splicing, with optical inspection (AOI) verifying solder joint quality. Post-splicing, the assembly undergoes thermal cycling (-40 to 125°C, 500 cycles) and vibration testing (10-2000 Hz) to ensure reliability. Standards like IPC-6012 specify splicing criteria, including minimum solder fillet size (≥0.2 mm) and insulation resistance (>10^10 Ω). This technology enables cost-effective production of large rigid PCBs, leveraging existing manufacturing capabilities while meeting the performance demands of large-scale electronic systems.