No abstract

One of the most important procedures in the electronics industry is the assembly of electronic components onto Printed Circuit Boards (PCB) through the soldering process. Among the various soldering methods available, wave soldering is a very effective technique. In this process, the components are placed onto the PCB, which subsequently, is coated with flux and then passed across a preheat zone. In the end, the assembly is moved by the conveyor and passed over the surface of the molten solder wave in order to create a reliable connection both mechanically and electrically. Although this process has been frequently used, there are soldering defects that remain unsolved and continue to emerge, such as the missing of surface-mount components in the PCB after the soldering process. Aiming to understand if such defects are related to the force exerted by the solder wave in the PCB, in the present work, a numerical and experimental study was performed. For this purpose, a Computational Fluid Dynamic model was developed by using the Fluent® software to describe the interaction between the solder jet and the PCB with the integrated circuits, and the multiphase method, Volume of Fluid, was also applied to track the solder-air interface boundary. The results obtained numerically were validated by using an experimental setup designed and built to this end. In general, the data obtained showed to be in good agreement and it was concluded that the force exerted by the solder wave is approximately 0.02 N.

Purpose This study aims to determine the minimum force required to pull out a surface mount component in printed circuit boards (PCBs) during the wave soldering process through both experimental and numerical procedures. Design/methodology/approach An efficient experimental technique was proposed to determine the minimum force required to pull out a surface mount component in PCBs during the wave soldering process. Findings The results showed that the pullout force is approximately 0.4 N. Comparing this value with the simulated force exerted by the solder wave on the component ( ≅ 0.001158 N), it can be concluded that the solder wave does not exert sufficient force to remove a component. Originality/value This study provides a deep understanding of the wave soldering process regarding the component pullout, a critical issue that usually occurs in the microelectronics industry during this soldering process. By applying both accurate experimental and numerical approaches, this study showed that more tests are needed to evaluate the main cause of this problem, as well as new insights were provided into the depositing process of glue dots on PCBs.

Manufacturing of electronic boards (commonly referred as PCB) is a highly automated process that requires an accurate control of the various processing variables. Amongst the soldering processes, wave soldering is one of the most often used. In this, the various electronic components are provisionally inserted onto the PCB, and a low velocity jet of melted solder is directed to the moving board. Due to capillarity effects the solder adheres to the component/board interface and the process is completed. This methodology is most often used for small components. The adjusting of the operating parameters (solder nozzle orientation and velocity) is often carried out on a trial and error basis resulting in a time consuming process that is at odds with the increasing demand for smaller production series that the electronics industry is faced with. In addition the number of defects (mostly from missing components that are washed away by the impacting jet) is more likely to occur when thinner substrates are used in the PCB manufacturing. The present paper describes the application of a Computational Fluid Dynamics model to describe the interaction of the solder jet with the PCB and the integrated circuits. The model includes the conservation equations for mass, momentum and energy in a transient time frame. The jet and surrounding ambient atmosphere are modeled as two separate fluids and the interface is tracked by a VOF model. By adjusting the computational mesh refinement the interface is captured with accuracy. The drag forces occurring in the various components are computed from the pressure data field. The model allows the optimization of the wave operating parameters as a function of the component type of and its layout in the PCB.