Investigating the influence of lead angle on optimising laser soldering parameters for improved pin-through-hole joint quality

Purpose This study aims to investigate the effect of lead angles on laser soldering parameters to improve the quality and reliability of pin-through-hole (PTH) solder joints. The lead angle, defined as the angle between the leads and the soldering surface, plays a crucial role in soldering performance. Variations in the lead angle can affect solder filling times, and deviations from the perpendicular position can cause defects such as incomplete fills or voids. Design/methodology/approach The numerical simulations carried out with ANSYS Fluent were validated through experimental methods conducted in industrial settings. The simulations, using the Finite Volume Method, were used to ascertain the optimal soldering parameters by assessing the impacts of lead angles between 82° and 90°. The optimal lead angle was identified through a detailed analysis of void ratio, filling time and solder flow behaviour in a PTH capacitor assembled on a printed circuit board (PCB) using a single-spot diode laser soldering process. Findings The simulation results demonstrate that lead angles significantly influence void formation, filling time and flow characteristics. An optimal lead angle of 84° was identified, minimising void ratios to 1.65%, achieving rapid filling times of 0.90 s for 96% PTH barrel coverage and ensuring favourable flow dynamics. Importantly, the simulation outcome aligned with experimental results from industrial settings and met the minimum-quality criteria outlined in the IPC-A-610 standard for solder joints. These findings offer valuable guidance for optimising laser soldering processes, reducing filling times to less than 1.0 s while maintaining high-quality joints with void ratios of less than 2%. Practical implications This research advances laser soldering technology, enabling the efficient assembly of next-generation microelectronics and facilitating the production of compact, high-performance devices that meet evolving market demands. It is expected to enhance solder joint reliability while driving further innovations in laser soldering processes. Originality/value Despite extensive research on laser soldering, there is a noticeable gap in studies focused on optimising lead angles in PTH applications. To the best of the authors’ knowledge, no prior research has used numerical simulations to evaluate the effects of different lead angles on solder joint quality in laser soldering for PTH devices.