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Parallel two-sided assembly lines are usually designed to produce large-sized products such as trucks and buses. In parallel two-sided assembly lines, both left and right sides of the line are used for manufacturing one or more products on two or more assembly lines located parallel to each other. The purpose of this paper is to develop a new mathematical model for the parallel two-sided assembly line balancing problem that helps to evaluate and validate the balancing operations of the machines such as removal of tools and fixtures and reallocating the operators.

The proposed approach is explained with the help of an example problem. In all, 22 test problems are formed using the benchmark problems P9, P12, P16 and P24. The results obtained are compared among approaches of the task(s) shared, tool(s) shared and both tool(s) and task(s) shared for effect on efficiency as the performance measure. The solution presented here follows the exact solution procedure that is solved by Lingo 16 solver.

Based on the experiments, line efficiency decreases when only tools are shared and increases when only tasks are shared. Results indicate that by sharing tasks and tools together, better line efficiency is obtained with less cost of tools and fixtures.

According to the industrial aspect, the result of the study can be beneficial for assembly of the products, where tools and tasks are shared between parallel workstations of two or more parallel lines.

According to the author’s best knowledge, this paper is the first to address the tools and tasks sharing between any pair of parallel workstations.

Crack and stress distribution on dies are key issues for the pressure-assisted sintering bonding of power modules. The purpose of this research is to build a relationship among stress distributions, sintering sequences and sintering pressures during the sintering processes.

Three sintering sequences, S(a), S(b) and S(c), have been designed for the double-side assembly of power module in this paper. Experiments and finite element method (FEM) analysis are conducted to investigate the crack and stress distribution.

The sintering sequence had significant effects on the crack generation in the chips during the sintering process under 30-MPa pressure. The simulation results revealed that the module sintered by S(a) showed lower chip stress than those by the other two sintering sequences under 30 MPa. In contrast, the chip stress is the highest when the sintering sequence follows S(b). The simulation results explained the crack generation and prolongation in the experiments. S(a) was recommended as the best sintering sequence because of the lowest chip stress and highest yield rate.

This study investigated the stress distributions of the double-side sintered power modules under different sintering pressures. Based on the results of experiments and FEM analysis, the best sintering sequence design is provided under various sintering pressures.

This paper presents a solder joint engineering reliability model — Solder Reliability Solutions** (SRS) — and its application to surface mount area‐array and chip‐scale assemblies. The model is validated by failure data from 33 accelerated thermal cycling tests, and test vehicles covering several generations of component, assembly and circuit board technologies and a variety of test conditions. The SRS model has been implemented as a PC‐based design‐for‐reliabilltytool that enables rapid assessment of assembly reliability in the early stages of product development.

Electronic packaging technologies, such as pin grid arrays, increasingly small pitch surface mount, and double‐sided assemblies are all aimed towards the highest possible product density, with improved performance. The gap between inspection effectiveness and advances made in packaging technologies is becoming larger. As efforts proceed, to learn more about critical factors influencing reliability of solder joints, it is prudent to ensure that printed wiring assembly (PWA) design rules evolve to permit the broadest range of anticipated automated inspection requirements. The range of automated inspection technologies can all be made more effective through careful design of electronics for inspection. Significant opportunities lie in both PWA layout and design, as well as electronic component design, tolerancing, and standardisation. Many inspection issues are shared, but with increased recognition of digital radiography's unique capabilities; this discussion will emphasise X‐ray inspection issues.

The emergence of new interconnection technologies involving double‐sided surface mounted components has put stronger restrictions on the method of preserving the solderable finish on printed circuit (PC) boards. The popular Sn/Pb coatings have come under strong scrutiny due to environmental hazards of lead and also because they do not provide flat, planar surfaces for SM assembly. Organic solderability preservative coatings (OSP) are emerging as strong contenders for replacing Sn/Pb surface finishes. Benzotriazole based organic coatings have been successfully used in the past by several electronics manufacturers. However, assembly technologies involving multiple thermal operations have necessitated a fundamental understanding of the thermal stabilities and the mechanism of corrosion protection provided by the OSPs. This paper reports the results of an investigation of the thermal stabilities of two organic corrosion protection coatings. Although both are organic azole based, they operate in two distinct regimes: one forming thin films (∼100 Å) and the other forming thick films (∼5000 Å). The mechanism of surface protection has been studied using direct surface analytical techniques such as X‐ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), scanning transmission electron microscopy (SEM/TEM) and Fourier transform infrared spectroscopy (FT‐IR). The solderability of the copper was measured by wetting balance techniques and correlated to the amount of copper oxidation. The results indicate that, although the thin films provide excellent protection for storage and handling operations, they decompose under heat, thereby causing oxidation of the copper. The thick films appear to withstand multiple thermal cycling. However, the underlying copper substrate can still be oxidised by oxygen diffusion through pores or cracks, or the film may undergo chemical changes that render the copper unsolderable.

To provide a good insight into solving a multi‐response optimization problem using neuro‐fuzzy model and Taguchi method of experimental design.

Over the last few years in many manufacturing organizations, multiple response optimization problems were resolved using the past experience and engineering judgment, which leads to increase in uncertainty during the decision‐making process. In this paper, a four‐step procedure is proposed to resolve the parameter design problem involving multiple responses. This approach employs the advantage of both artificial intelligence tool (neuro‐fuzzy model) and Taguchi method of experimental design to tackle problems involving multiple responses optimization.

The proposed methodology is validated by revisiting a case study to optimize the three responses for a double‐sided surface mount technology of an electronic assembly. Multiple signal‐to‐noise ratios are mapped into a single performance statistic through neuro‐fuzzy based model, to identify the optimal level settings for each parameter. Analysis of variance is finally performed to identify parameters significant to the process.

The proposed model will be validated in future by conducting a real life case study, where multiple responses need to be optimized simultaneously.

It is believed that the proposed procedure in this study can resolve a complex parameter design problem with multiple responses. It can be applied to those areas where there are large data sets and a number of responses are to be optimized simultaneously. In addition, the proposed procedure is relatively simple and can be implemented easily by using ready‐made neural and statistical software like Neuro Work II professional and Minitab.

This study adds to the literature of multi‐optimization problem, where a combination of the neuro‐fuzzy model and Taguchi method is utilized hand‐in‐hand.

Heraeus of Hanau, W. Germany, have introduced a new solder paste (Series SC 3300), designed for SM technology. Heraprint and Cermalloy solder paste formulations eliminate the formulation of solder balls during reflow, thus assuring very high yields. The organic system in these materials prevents crusting and viscosity changes while providing rheology characteristics which allow improved screen printing resolution.

The need for better performance, safety and comfort is the driving force behind the dramatic growth in car electronics. The key to success depends mainly on system reliability and cost which in turn are related to the choice of technological approach. The basic topics to be investigated are, on the one hand, system architecture and, on the other, the implementation techniques involved. Large scale integration of a consistent portion of the system will be necessary but other factors such as interconnections, packages and so on must also be taken into account. The variety of boards, components and assembly techniques currently available are just adequate for present needs, but for the 1990s the continuously increasing complexity of automotive electronic systems will probably necessitate better use of what is available and possibly new ideas.

Organic solderability preservative (OSP) coatings are not new. They have been used successfully with aggressive water soluble flux for assembly of through‐hole only PWBs. However, the multiple heating cycles required for mixed technology assembly and use of no‐clean low solids flux (LSF) for wave solder assembly have placed a greater demand on the solderability protection provided by OSPs. Wetting balance and float testing were used to evaluate numerous OSPs as well as the potential for these surface finishes to be used for ‘No‐Clean’ assembly. Although these laboratory evaluations revealed that OSPs are not as robust as SnPb, they did indicate the assembly processes and materials which could work with OSPs. Additional simulated assembly trials with test vehicles confirmed that thick OSP pre‐flux coatings interfere with soldering and that the solderability of surfaces with thin OSPs degrades when heated in an air environment. Since none of the OSPs evaluated outperformed the imidazole currently in use at AT&T, a no‐clean LSF assembly production trial with a mixed technology telecommunication circuit pack was conducted to compare imidazole with hot air solder levelled surfaces. The production trial and laboratory evaluations resulted in the development of an application model. The elements of the application model are not complicated: (1) use thin OSPs, (2) avoid baking, (3) use as aggressive a flux as possible, (4) apply as much flux as possible, (5) apply the flux where you want solder to wet, and (6) use nitrogen inerted processes whenever possible. Combination of these elements has led to the successful implementation of OSPs for no‐clean assembly. Funding for this effort was obtained through the National Center for Manufacturing Sciences (NCMS) Printed Wiring Board Interconnect Program.