A simplified model of the reflow soldering process

Abstract

• This is a conference paper and the definitive version is also available at: http://ieeexplore.ieee.org. Personal use of this material is permitted.However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. ABSTRACTPrevious models of the reflow soldering process have used commercial finite difference (FD) or computational fluid dynamics simulation software to create detailed representations of the product and/or the reflow furnace. Such models have been shown to be highly accurate at predicting the temperatures a PCB design will achieve during the reflow process. These models are however complex to generate and analysis times are long, even using modern high performance workstations. With the move to adopt lead free soldering technology, and the consequently higher reflow process temperatures, optimisation of the reflow profile is gaining a renewed emphasis. This paper describes a less complex approach to modelling of the process, which uses simplified representations of both the product and the process, together with a FD solver developed specifically for this application, and which achieves an accuracy comparable with more detailed models. In order t o establish an accurate representation of the specific reflow furnace being simulated, a reflow logger is used to make measurements of the temperature and level of thermal convection at each point along the length of the furnace for a small number of carefully chosen reflow profiles. The temperatures for any other reflow profile can then be predicted from these measurements.

Integrated Approach to Obtain Gas Flow Velocity in Convection Reflow Soldering Oven

“…There are several ways to simulate the reflow soldering process, including the finite element method (FEM) [4], finite volume method (FVM) [5,6], fluid-structure interface (FSI) [7], lattice Boltzmann's method (LBM) [8], discrete phase method (DPM) [9] and molecular dynamic (MD) [10]. Whall et al [11] used ANSYS finite element analysis software to conduct temperature field simulation of 2-D PCBA components and obtained simulated temperature data. Gong et al [12] simulated the reflow soldering process and optimized the temperature profile by establishing the FE model of PCBA assembly containing a ball grid array (BGA) component and genetic algorithm (GA) optimization.…”