Pusat Pengajian Kejuruteraan Mekanikal - Monograf

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Browsing Pusat Pengajian Kejuruteraan Mekanikal - Monograf by Author "Alfred, Lim Zhi Chyi"

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    Optimization of laser soldering parameters on passive devices.
    (2024-07)
    Alfred, Lim Zhi Chyi
    Laser soldering is a non-contact process that is crucial in the soldering technology for miniature electronic components as it is capable of providing localized heating at specific region by emitting a high-energy laser beam. The process is highly sensitive to variations in process parameters, leading to inconsistent solder joint quality and defects such as solder bridges and voids. To optimize the process, several studies has utilized numerical simulations to investigate effect of various process parameters on the solder joint reliability. However, there are many more parameters that may influence the solder quality are yet to be fully understood or optimized, such as lead-to-hole ratio and lead length. Therefore, this study will serve to investigate the effect of different configurations of lead-to-hole ratio and lead length/protrusion on solder joint reliability by means of numerical method, which is then validated experimentally in WD. Finite Volume Method (FVM) is implemented in the simulation modelling for solder flow filling behaviour of SAC305. Experiments were conducted to serve as benchmark for evaluation of numerical simulations’ accuracy and its predictive power. By comparison, the results of numerical simulation and experimental data show good agreement, whereby the height of solder joint in simulation is found out to be 0.58 mm, which is virtually identical to the measurement in experiment, that is 0.577 mm. The findings showed that optimal solder joint with the least void formation could be achieved by setting the lead-to-hole ratio as 0.5 and lead protrusion as 1.8 mm. The choice for optimized parameters investigated in this research are justified through the solder flow’s velocity and pressure distribution throughout the simulation time steps. The findings showed that potential void formation site is likely to be associated with low-pressure region within the molten solder, where the air is entrapped easily. In addition, thermal distribution from numerical simulation could be used to pinpoint potential location of the thermal stress built-up, allowing preventive measure against failures in electronic assemblies.