Q-Flex (United States)

Flexible printed cables and circuitry based on copper-polyimide materials are widely used in experiments looking for rare events due to their unique electrical and mechanical characteristics. However, past studies have found copper-polyimide flexible cables to contain 400-4700 pg 238U/g, 16-3700 pg 232Th/g, and 170-2100 ng natK/g, which can be a significant source of radioactive background for many current and next-generation ultralow background detectors. This study presents a comprehensive investigation into the fabrication process of copper-polyimide flexible cables and the development of custom low radioactivity cables for use in rare-event physics applications. A methodical step-by-step approach was developed and informed by ultrasensitive assay to determine the radiopurity in the starting materials and identify the contaminating production steps in the cable fabrication process. Radiopure material alternatives were identified, and cleaner production processes and treatments were developed to significantly reduce the imparted contamination. Through the newly developed radiopure fabrication process, fully-functioning cables were produced with radiocontaminant concentrations of 20-31 pg 238U/g, 12-13 pg 232Th/g, and 40-550 ng natK/g, which is significantly cleaner than cables from previous work and sufficiently radiopure for current and next-generation detectors. This approach, employing witness samples to investigate each step of the fabrication process, can hopefully serve as a template for investigating radiocontaminants in other material production processes.

Resumo. O setor de máquinas e implementos agrícolas desempenham atualmente um importante papel tanto para a economia quanto para geração de empregos no Brasil. Mesmo com todo o crescimento apresentado pelo setor, existem aspectos que precisam ser observados, tendo em vista um mercado consumidor cada vez mais exigente por produtos de qualidade que atendam suas necessidades e expectativas. Logo, tendo em vista que a gestão da qualidade é indispensável para que uma organização consiga estar ativa no mercado e levando em consideração que não existem na literatura muitos materiais que relatem o gerenciamento da qualidade em indústrias deste segmento, o presente trabalho se propôs a realizar uma pesquisa objetivando identificar o estado da arte da gestão da qualidade no setor de máquinas e implementos agrícolas em publicações brasileiras. Para tanto foi realizada uma pesquisa bibliográfica com abordagem bibliométrica de produções científicas publicadas entre os anos 2000 e 2021. Mediante a revisão dos trabalhos selecionados foi possível verificar que a gestão da qualidade tem baixa representatividade nas publicações que tratam especificamente do setor de máquinas e implementos agrícolas. Os enfoques com maior prevalência dentro das indústrias deste segmento foram a qualidade baseada no usuário e a qualidade baseada no processo, as ferramentas mais utilizadas foram o 5S e o QFD, que inclusive trouxeram benefícios em termos de melhoramento dos processos, do envolvimento dos colaboradores com o ambiente de trabalho, e do atendimento às expectativas e necessidades dos clientes.

Flexible circuits (copper clad polyimide) are an integral part of the majority of multifunctional structures. Multifunctional structures have been cited over recent years as an enabling techno logy for lightweight flight vehicles such as microspacecraft and interceptors. Although flexible circuits have found a wide acceptance in commercial electronics, their usage in flight hardware particularly in module -to -module interconnects has been almost non -existent. The primary reasons include lack of familiarity, minimal design rules, concerns with shielding systems and interfaces with standard circular and rectangular connectors. AFRL and MDA have funded both an STTR Phase II and an SBIR Phase II to provide solutions to these problems and provide demonstration hardware and methodology. Key advantages of defense programs' use of this technology include large savings in cable mass and volume (> 50%), cost savings through the elimination of touch labor , test point exposure through flex extensions at any location and the use of distributed active and passive components for data processing and sensors. The efforts in both the Phase I and Phase II tasks have focused on Northrop Grumman Global Hawk cabling systems and the Boeing Delta IV launch vehicle. Methods have been developed to provide a mix of shielding depending upon environmental and signal integrity needs. The shielding can be designed to be continuous from one end to the other while still suppo rting rework. Cladding materials are in development to prevent abrasion and damage in flight environments. A novel interconnect to a standard D38999 connector has been developed to permit carrying the shield layers through and permitting a transition cab le to be manufactured that interfaces to existing hardware. Design rules and guidelines are in place to support contractors as they transition into flexible circuit design and incorporation.

CSP's and /spl mu/BGA's are becoming more common in the market place and present new challenges for stacking of devices. An investigation into possible methods of stacking these devices was undertaken. New materials such as z-axis epoxies and combination flux/underfill epoxies were considered as well as the possibilities of adhesiveless copper on flex for fine line etching. This paper describes the basic approach and the results of combining the new technologies into a versatile and novel stacking approach.