Resumen de Métodos alternativos de fixação para componentes de circuitos impressos
The growing demand for innovation and the ever-shorter product lifespan result in a great amount and diversity of waste disposal at dumps and landfills. One of the fastest growing waste types nowadays is e-waste. Consequently, Printed Circuit Boards (PCBs), which are the basis of the electronic industry, have become a serious social problem and a threat to the environment. Wasted PCBs recycling processes, therefore, have been extensively investigated. These processes can be quite complex and expensive since the recycling of PCBs involves a variety of materials and components that are not easily separated. Recently, there has been a change in the way PCBs are fixed. The traditional Sn-Pb solder has been substituted for a Lead-Free solder in an attempt to minimize the toxic composition of the first. Nevertheless, this substitution has not solved the problem of component separation for future reuse and/or recycling. The present work aims at developing and testing possible alternative fixing methods for the components in printed circuits without the use of a metallic solder in order to facilitate its subsequent recycling process. The first step was the study of the components and materials present in PCBs with emphasis on the types of solders used and the required fixing properties. Then, new fixing methods were proposed, followed by the development of prototypes and tests. These initial tests were undertaken in a laboratory at the Vilanova i La Geltrú Campus, Universitat Politècnica de Catalunya (UPC) in Spain. At this stage, the main objective was to test the initially chosen proposal for further studies. The final tests, comparing the ultimate proposal with boards that employ commercially conventional fixing systems were done at Instituto Tecnológico em Ensaios e Segurança Funcional (Itt Fuse), Universidade do Vale do Rio dos Sinos (UNISINOS) in Brazil. The final prototype version was assembled by a PCB company to ensure its reliability. Thermal cycling, vibration and salt-spray tests were conducted with continuity and inspection x-ray visual analysis both during and after the tests. The tests showed that, for the type of product proposed (reliability category product class 1), norm IPC-A-600G (IPC, 2004), the ultimate proposal for a Concept board fulfilled all functioning requirements when compared to the traditional Sn-Pb and the Lead-Free systems. Thus, results point at potential further studies on the environmental impact of this alternative type of PCB.
