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Adhesives have become an integral part of the surface mount process. Either to hold the components on the bottom side of a Printed Circuit Board (PCB), or as a substitute for solder paste, the application of adhesives will influence the surface mount process for a long time in the future. Stencil printing, is probably, the simplest, fastest, most economical and robust process for depositing the surface mount adhesives on to a PCB. It has gained a lot of attention in recent years, because of the development of newer adhesive materials with printable rheology and the importance of throughput improvement programs in electronic assembly facilities. Also, the need to handle different types of products demands a highly flexible assembly process. The stencil printing of adhesives lends itself better to different product types than the conventional dispensing process. This research had two major objectives - to develop a robust process for the stencil printing of surface mount adhesives, and to conduct an initial feasibility study for the simultaneous reflow of solder paste and cure of adhesives. The automotive electronics environment was the focus of this research. Two different stencil materials, the conventional steel stencil and the new polymer stencils, were evaluated using detailed Design of Experiments (DOE) based methodology. Stencil design was ¡®optimized¡¯ for both these stencils. Production-related issues associated with these stencil materials were outlined and discussed. The adhesive selected was qualified for use in an automotive electronics environment by performing detailed material qualification tests. In order to assist in successful implementation, comprehensive training and documentation were completed. As a continuation of the adhesive printing research effort, the process of the simultaneous reflow of solder paste and the cure of surface mount adhesives was investigated. Simultaneous reflow of solder paste and cure of surface mount adhesives is an attractive alternative from a floor-space savings and throughput improvement perspective. It is not yet widely used due to potential materials and process-related issues. This research established the feasibility of the simultaneous reflow and cure process. The contamination of adhesive deposits due to flux residues was analyzed. In addition, the economic feasibility of this process was studied with recommendations for implementation.


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