Search

Purpose Reflow soldering process is an important step of the surface mount technology. The purpose of this paper is to minimize the maximum warpage of shielding frame by controlling reflow soldering control parameters.Design/methodology/approach Compared with other reflow-related design methods, both time and temperate of each extracted time region are considered. Therefore, the number of design variable is increased. To solve the high-dimensional problem, a surrogate-assisted optimization (SAO) called adaptive Kriging high-dimensional representation model (HDMR) is used.Findings Therefore, the number of design variable is increased. To solve the high-dimensional problem, a surrogate-assisted optimization (SAO) called HDMR is used. The warpage of shield frame is significantly reduced. Moreover, the correlations of design variables are also disclosed.Originality/value Compared with the original Kriging HDMR, the expected improvement (EI) criterion is used and a new projection strategy is suggested to improve the efficiency of optimization method. The application suggests that the adaptive Kriging HDMR has potential capability to solve such complicated engineering problems. [ABSTRACT FROM AUTHOR]

Purpose - This paper aims to reveal the causes and find an efficient method to compensate the shrinkage to reduce failure costs. Reflow-induced printed circuit board (PCB) shrinkage is inspected in automotive electronics production environment. The shrinkage of two-sided, large PCBs results in printing offset errors and consequently soldering failures on smaller components during the reflow soldering of the second PCB side. Design/methodology/approach - During the research, the investigations had to adapt to actual production in an electronics manufacturing plant. A measurement method was developed to approximate the overall shrinkage of the given product. With the shrinkage data, it is possible to perform an efficient compensation on the given stencil design in computer-aided manufacturing environment. Findings - It was found that even with the investigated lower-quality PCB materials, the compensation on the stencil significantly reduces the quantity of failures, offering an efficient method to improve the yield of the production. Research limitations/implications - Research was oriented by the confines of production (fixed PCB sources, given PCB materials, reflow process and production line), where an immediate solution is needed. Future investigations should be focussed on the PCB parameters (different epoxy types, glass-fibre reinforcements, etc.). Practical implications - The optimised production reduces overall failure costs. The stencil re-design and application is a fast and efficient way to immediately act against the shrinkage-induced failures. The method was successfully applied in automotive electronics production. Originality/value - The paper presents a novel approach on solving an emerging problem during reflow. [ABSTRACT FROM AUTHOR]

Purpose - The purpose of this paper is to propose a new surface model combining the eccentric shell with multi-point constraint (MPC) for warpage prediction of injection molded plastics. Design/methodology/approach - In this paper, three benchmark tests and a practical example are implemented to evaluate the performance of the new surface model and existing models. Findings - The results demonstrate that the proposed model could give satisfactory solutions and has advantages over the existing models. Practical implications - More precisely predicted warpage field for injection molded plastics can be achieved with the purposed model, such as that in the practical case. Originality/value - The surface models are efficient and still popular for practical injection molding analysis. However, the existing models for warpage prediction cannot properly represent the true strain energy and obey material continuity assumption, and also they have not been assessed rigorously by benchmark tests. To overcome above-mentioned difficulty, a new surface model is proposed, which employs the eccentric shell without shear factor and MPC equation that ensuring material continuity. The results from experiment illustrate that the new model is superior to existing models. [ABSTRACT FROM AUTHOR]

Considers a process for better mechanical design of printed circuit boards (PCBs) which suffer from warpage during the assembly process. During the reflow process, PCBs experience a wide range of temperatures, i.e. from ambient temperature to the peak temperature reached in the furnace. Out-of-plane deflections are generated, due to the mismatch in the thermal expansion properties of the materials comprising the PCB. In this study, the focus is on setting up the analysis procedure and constructing a finite element model of the board deflections. The weight of the components mounted on the PCB and the effect of soldering are ignored, due to the complexity of the additional data required. A set of real PCBs was also exposed to the reflow process and the resulting deflection measured for comparison with the model. The combination of properties of the board material and copper plating is further researched in order to investigate the cause of problems and improve design. [ABSTRACT FROM AUTHOR]