Issue link: https://iconnect007.uberflip.com/i/1540984
88 SMT007 MAGAZINE I NOVEMBER 2025 Process Controls for Long Storage Specify packaging and storage (sealed barrier bags, desiccant, controlled temperature/RH) and re-bake or re-tin triggers by date code or measured solderability drift. Also, maintain lot-level traceability linking steam- aging conditions, test data, and final disposition. Conclusion Under MIL-STD-883 Method 2003, the dipped por- tion of each termination must show ≥95% contin- uous solder coverage. Visual defects—pinholes, voids, porosity, non-wetting, or de-wetting—may not exceed 5% of the dipped area. This matters because solderability is a first-order driver of assembly yield and long-term reliability. Since the porous-finish failures of the 1980s, industry standards and test protocols have matured to pre- vent recurrence and to ensure robust interconnects. To Meet the Bar: • Use dip-and-look for fast, visual confirmation of coverage and defects • Use a wetting balance for quantitative sensi- tivity to finish, flux, alloy, and aging effects • Pair methods with sound process control—docu- mented flux/solder/bath conditions, disciplined pre-cleaning, and consistent specimen prep • Include aging simulations (e.g., steam aging) where life cycle demands warrant it, and cor- relate results with cross-sections or mechani- cal tests when reliability is critical Taken together, these practices verify surface condition, validate long-term performance, and help deliver reliable, standards-compliant assemblies that stand up to stringent industrial, automotive, medical, aerospace, and defense requirements. SMT007 Nash Bell is president of BEST, Inc. To read past columns, click here. K N O C K I N G D OW N T H E B O N E P I L E Drivers of Electronic Platforms of Tomorrow Electronic structures and assembly materials and technologies are undergoing radical changes. For example, electronic structures and interactive HMIs (human machine interfaces) in consumer and au- tomotive electronics are undergoing rapid trans- formation. Furthermore, electronic circuits and de- vices are being integrated with displays using nov- el packaging and assem- bly techniques to produce aesthetically compelling, compact, interactive, and lightweight structures. These structures can take The Printed Circuit Assembler's Guide to... Low-Temperature Soldering, Vol. 2 Chapter 6: The Dawn of Ultra Low-temperature Solders BOOK EXCERPT By Morgana Ribas, Pritha Choudhury, Ramakrishna H V, and Rahul Raut, MacDermid Alpha Electronics Solutions a variety of formats including flat, slightly curved (2.5D) and full 3D. Furthermore, human machine interfaces (HMIs) are transitioning to tactile, smart, interactive struc- tures from their current physical and mechani- cal forms. These emerging capacitive touch smart structures are replacing traditional switches and knobs in many next-generation devices. To facilitate these next-generation structures and devices, flexi- ble PCBs, novel assembly technologies, and integra- tion approaches are needed. To enable this crucial technological shift, an en- tire ecosystem must be developed. This ecosystem should comprise high-performance and high-reliabil- ity materials, as well as high-volume, high-yield, and sustainable manufacturing processes. Continue reading...