SMT Magazine

SMT-Apr2017

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64 SMT Magazine • April 2017 The storage of moisture sensitive electronic components and materials is problematic, and manufacturers with long term storage require- ments face additional obstacles. Requirements for long-term storage are in- creasing. Why? 1. Component Obsolescence Due to rapid changes in packaging design and material, companies find themselves forced to purchase additional quantities of compo- nents in order to guard against the impact of component obsolescence on their final product designs. This in turn creates an issue of long- term inventory storage. 2. Short Product Lifecycles Product lifecycles have become very short with new models being released sooner than ever before. However, many manufacturers in industries including automobiles, aviation and avionics, military and railway must guarantee the availability of replacement parts including PCBs for ten or even twenty years. This demands the advance purchase and extended storage of components and materials. Further complicat- ing the problem is that most components can- not be stored for more than a few years without very special handling procedures. Risks The biggest danger posed is humidity. It is the cause of two of the biggest defect causes: ox- idation and diffusion. Because of surface oxidation, components and PCBs can suffer from reduced solderablity, which often results in complete failure. Diffu- sion of vapor and noxious substances in the in- ner structure of the components or PCBs can result in long-term disintegration of conductor paths and insulation layers. Both risks can be avoided by correct handling and dry storage. The Oxidation Process— Contact Corrosion In an ultra-dry atmosphere, there is no cor- rosion. For corrosion to occur, two demands must be met: there must be a means of oxida- tion and a watery solution, which works as an electrolyte. by Rich Heimsch SUPER DRY-TOTECH EU Solutions for Long-term Storage of Electronic Components and Compositions MORE THAN JUST DRY AIR

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