SMT Magazine

SMT-Dec2017

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44 SMT Magazine • December 2017 work [5-7] by fundamental considerations. There- by different values for the area ratio will be part of the investigation, which are purposely set to very low limits. The influence of the aperture shape and orientation on the solder printing perfor- mance will be discussed. It is based on differ- ent forms of rectangles. Starting with a square the dimensions are incrementally changed, so that the square converts further into a rectan- gle. Furthermore, each rectangle is additional- ly rotated by 90° to be able to evaluate the in- fluence of the apertures direction towards the squeegee. In addition to the previously described sten- cil aperture attributes, this research also explores different stencil thicknesses, solder pastes and a variation of the squeegee speed. The evalua- tion of all data will be based on the two crite- ria of transfer efficiency and standard deviation. For both experiments the same stencil layouts and same solder paste are being used. The paper concludes with an outlook and suggestions on the modification of the current calculation by limitations of aperture dimensions. FEATURE by Stefan Härter, Jens Niemann Jörg Franke, INSTITUTE FOR FACTORY AUTOMATION AND PRODUCTION SYSTEMS (FAPS); Friedrich-Alexander UNIVERSITY ERLANGEN-NÜRNBERG (FAU); and Jeff Schake and Mark Whitmore ASM ASSEMBLY SYSTEMS The ongoing miniaturization trend in the SMT production induces new challenges and highly integrated systems. In passive compo- nents, the miniaturization leads to the intro- duction of the EIA size 01005 or smaller. Typ- ical 01005 components are chip resistors and chip capacitors with the dimension of 0.4 mm x 0.2 mm. Despite numerous publications in this field already addressing the printing of such de- vices, a defined wholly optimized process re- mains unsolved and inspires further novel re- search ideas on this topic. This paper focusses on the stencil printing process, because the highest amount of failure is assumed to be based on this process step. [1-4] Furthermore, the paper extends the preliminary

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