SMT Magazine

SMT-Sept2017

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46 SMT Magazine • September 2017 four segments. Each segment displays one component corner. Alignment is supported in large magnification. Matching of pins and pads becomes much easier for the operator's eyes. Summary and Future Outlook Even if production quality throughout the electronic industry is constantly rising, rework will remain a challenging topic for the next decades. Electronic assemblies are reaching higher integration and a generally increasing complexity. The rework system supplier's task will be to follow these market movements and offer solutions that provide the ability to rework boards successfully. At the same time the degree of automation will rise in the segment of rework equipment, and operator assistance will become more important. Besides technological challenges as many features as possible of the high end rework systems need to find their way down to the entry level rework units as a spin off. Commercial and environmental benefits due to less scrap and electronic waste will thus be achieved. SMT References 1, 2. Wikipedia: "Void" in soldering defect and surface mount technology. Editor's Note: This article was originally presented at the technical proceedings of IPC APEX EXPO 2017. Joerg Nolte is the product manager for tools, rework and inspection systems at Ersa GmbH. BTC AND SMT REWORK CHALLENGES Research at the National Institute of Standards and Technology (NIST) may have found that sub- tlety solves some of the issues with a novel memo- ry switch. This technology, resistive random access mem- ory (RRAM), could form the basis of a better kind of nonvolatile computer memory, where data is re- tained even when the power is off. RRAM could surpass flash in many key respects, it has yet to be broadly commercialized because of technical hur- dles that need addressing. One hurdle is its variability. A practical memo- ry switch needs two distinct states, representing either a one or a zero, and component design- ers need a predictable way to make the switch flip. Conventional memory switches flip reliably when they receive a pulse of electricity, but we're not there yet with RRAM switches, which are still flighty. In two recent papers, the research team has found a potential solution. The key lies in control- ling the energy delivered to the switch by using multiple, short pulses instead of one long pulse. "Shorter pulses reduce the variability," NIST guest researcher David Nminibapiel said. "The is- sue still exists, but if you tap the switch a few times with a lighter 'hammer,' you can move it grad- ually, while simultaneously giving you a way to check it each time to see if it flipped success- fully." Because the lighter touch does not push the switch significantly from its two tar- get states, the overlapping issue can be significantly reduced. Nminibapiel added that the use of shorter pulses also proved instru- mental to uncovering the next serious chal- lenge for RRAM switches—their instability. NIST Scientists Push Us Closer to Flash Memory Successor

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