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44 The PCB Design Magazine • November 2017 sumer market, or in low-volume production. We are also seeing more package-on-pack- age (PoP) type components being used in the industry. You should carefully check whether the assembly house is familiar with the tech- nology and the extra costs it might involve. Of course, smaller components are space saving, which could produce a cheaper board, as long as it doesn't mean making it more complex, with several levels of microvias or adding bur- ied structures etc. One invariably has to weigh up the space contra complexity issues at the de- sign phase. PCB producers should be involved right at the very start to help customers find the right solution. One must realize that there are real differences between producing prototypes and volume production. If you focus on the wrong things from the start, it could jeopardize the en- tire project if you find that your design can't be applied in volume production. We recommend initiating a seamless project together with your PCB producer at an early stage to ensure that the board can be manufactured at a reasonable cost, with the right level of complexity for the design and for reliable yields. Contact NCAB Group for a complete list of HDI guidelines. PCBDESIGN Chris Nuttall is chief operations officer at NCAB Group, responsible for global operations and technology. HDI PCBS: MAKE THE RIGHT CHOICE FROM DESIGN TO VOLUME Nanomaterials have been widely studied and proven to have unique properties that make them more suited to a variety of applications. Howev- er, there is still a need to better understand their structure and property evolutions from nanoscale to macroscale as well as transform nanoscale ma- terials into functional devices using scalable and low-cost manufacturing processes. Yanliang Zhang, assistant professor of aero- space and mechanical engineering and faculty member in the Center for Nano Science and Tech- nology at the University of Notre Dame, is work- ing to do both. He and his team are developing an innovative and highly scalable ad- ditive manufacturing process that may hold the key to transform the nano- materials into multi- functional devices. Their work aims to fabricate high- performance and flexible energy har- vesters, sensors and electronic devices. Zhang and his team are focusing their efforts on two projects in particular, one funded through a National Science Foundation CAREER Develop- ment Award and one funded through the U.S. De- partment of Energy. Through the NSF project, they will be study- ing the additive printing and sintering processes of colloidal nanocrystals to control thermoelectric and electronic properties in printed structures. They are working to establish a scalable and cost- effective additive manufacturing process to fabri- cate flexible thermoelectric and electronic films. Zhang's team is also developing advanced 3D conformal sensors using additive manufac- turing through a DOE project. Printing the sensors directly onto components enables high measurement accu- racy with minimal intru- sion. This research has the potential to estab- lish a new sensor manu- facturing paradigm for a broad range of in- dustrial applications. Additive Manufacturing May Hold Key to Transforming Nanomaterials into Multifunctional Devices