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42 SMT Magazine • October 2015 by Khurrum dhanji iMagineering inc. Many new and unique processes enable quick-turn assembly in 24 hours rather than days. Latest innovations include state-of-the-art machines, such as the stencil-less jet printer, and a proprietary PCB assembly turnkey quote system that gives customers a quote in minutes—not in days or weeks—and a fully assembled prototype PCB in 24 hours, after receipt of all materials. Multi-day lead times for PCB assembly are a thing of the past as a few advanced thinking as- semblers have worked hard to remove the time- related road blocks, enabling quick prototype assembly. New software such as Instant PCBA Quotes Online allows you to receive a guaranteed quote in minutes. The second major time-related hurdle to be eliminated was the cost of buying and waiting for the solder paste stencil to be manufactured and delivered. A new disruptive technology, the advanced solder paste inkjet, is an in-line soldermask printer that allows in- stant changes between assembly jobs. Full and instant 3D printing of different thicknesses of solder paste, improved start-to-delivery time for prototype PCB assembly, and significantly improved soldering quality eliminates 90% per- cent of the rework time. With reduced product development times, the electronic manufacturer's requirement for PCB assembly is 24 hours, enabling continued rapid development of a new product that will not stall at the final stage. Stencil-less Jet Printing For many years, stencil printing has been the standard and durable method of deposit- ing solder paste on surface mount assembly PCBs, but difficulties often significantly slowed down a change from one product to another in the assembly operation, as well as added cost. A significant challenge in newer, small- er electronics assembly is the huge difference of size among components. Therefore, trying to apply the right amount of solder paste for each component with one stencil is difficult. The biggest problem is how to produce quick- turn prototypes without disrupting series pro- duction that is already running in the line. Product changeover requires time-consuming tweaks to the stencil printing process, while unnecessarily shutting down an expensive as- sembly line to change the product. The inabil- ity of the stencil's technology to vary solder paste volume by part, on the run, remains the biggest impact on the soldering quality. Solder paste parameter optimizing after set up can take considerable time away from pro- FeATure Technologies to Enable Quick-Turn PCB Assemblies