The Modeling And Simulation Of Thermal Warpage Of PCBA During The Reflow Soldering

Reflow soldering is very important technics in SMT.Thermal impact to PCBA during reflow soldering is considered one of the main drivers for manufacturing defects.The materials making up a PCBA is various,and the thermal property of the materials is also different ,this may cause some defects for example wargpage.Excessive warpage in the PCB may result in gaps forming between the module leads and the molten solder on the solder pads,then the failure of electronical and physical connection lead to PCBA's defect.The traditional approach of experimentally analysing production defects would be costly and virtually impossible,and can't reach the demand of the producer for the fast renovation and the acute competition.An alternative to this approach is to derive computational and numerical models that encapsulate representations of the key process physics, so that effect analysis of the pertinent process variables may be examined. The application of the modelling and simulation to a sample PCBA has been carried out to explore how undue variations in the reflow temperature can be minimized by a number of different strategies. It has been shown that simple movements of components can have quite beneficial effects on the overall process thermal history of the PCA. It has also been demonstrated that modelling and simulation can be used to identify appropriate process ovens for a product. The paper use finite element analysis method analysis the thermal impact of PCBA during the reflow soldering ,and building the temperature and stress distribution model.The paper model and simulate the thermal warpage of PCBA during reflow soldering ,get the temperature and stress distribution of PCBA. this paper simulate the temperature distribution of PCBA under the condition of the material making up PCBA is different ,and PCBA will go through different oven section,building a simple physical model of a 4-layer PCB with 3 PLCCs to simulate the thermal stress and warpage of PCBA under three constrained conditions,when the PCBA go through the oven sections .Compared the surface displacement and the Z axis displacement of three points on the PCB under the three constrained condition to get the result of following.The thermal warpage happened under the constrained conditions of the two points on the cross were constrained is large than that happened under the constrained conditions of the four points were constrained .the thermal warpage happened under the constrained conditions of the four points were constrained is large than that happened under the constrained conditions of the two sides were constrained.Optimize the temperature figure is attainable through the simulation ,and the temperature distribution of PCBA is more uniform,also the warpage is minimized by adjusting constrained condition.