Improving the temperature field model of hot air reflow soldering based on reverse problem analysis

Le résumé fourni par la source

Hot air related reflow soldering is widely applied in the manufacturing of the electronic product, especially in the surface mounting assembly. During the reflow soldering process, the solder joints between the packaging lead and the solder pad of the board which have a great influence on the reliability of the electronic product are formed and determined by the its temperature profile. Thus, the temperature profile of the solder joints becomes critical. The most usual technique of the optimizing the temperature profiles is mainly dependent on several repeated test. This method is time-consuming and inefficient. The simulation-based method is considered promising for its efficiency. However, due to the complicity of the soldering mechanism, the accuracy of the simulation is not satisfied yet for the industry requirement in most cases. In this paper, a new modeling based on the reverse problem analysis is brought out for the simulation of the soldering process. Firstly, the PCBA assembly is tested in the hot air soldering process and the temperature profiles of the eight specific points on the PCBA are obtained. Secondly, the temperature model is conducted based on the Fluent code and the temperature profiles of the PCBA board is simulated. Thirdly, the temperature deviation between the test and the simulation is analyzed and the main affecting factors are determined by the sensitivity analysis. Aiming to reduce the deviation above, a reverse problem analysis of the temperature filed is performed. The accuracy of the temperature simulation is improved by solving the reverse problem and the improved temperature model of the hot air soldering reflow is derived.The results show that the air flow velocity of the furnace oven of 7, 8, 9, 11 and 12 has the greatest influence on the temperature. The reverse analysis of the whole process finally shows that the proportion of temperature difference greater than 20K is initially about 30%, and the proportion of temperature difference greater than 20K with reverse analysis is about 6%, which proves that the modeling method based on reverse problem analysis is effective. The method based on reverse problem analysis proposed in this paper offers meaningful insight and improves the accuracy for the temperature simulation of the hot air soldering process.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.