Design, evaluation, and control of nexus: a multiscale additive manufacturing platform with integrated 3D printing and robotic assembly.

Additive manufacturing (AM) technology is an emerging approach to creating three-dimensional (3D) objects and has seen numerous applications in medical implants, transportation, aerospace, energy, consumer products, etc. Compared with manufacturing by forming and machining, additive manufacturing techniques provide more rapid, economical, efficient, reliable, and complex manufacturing processes. However, additive manufacturing also has limitations on print strength and dimensional tolerance, while traditional additive manufacturing hardware platforms for 3D printing have limited flexibility. In particular, part geometry and materials are limited to most 3D printing hardware. In addition, for multiscale and complex products, samples must be printed, fabricated, and transferred among different additive manufacturing platforms in different locations, which leads to high cost, long process time, and low yield of products. This thesis investigates methods to design, evaluate, and control the NeXus, which is a novel custom robotic platform for multiscale additive manufacturing with integrated 3D printing and robotic assembly. NeXus can be used to prototype miniature devices and systems, such as wearable MEMS sensor fabrics, microrobots for wafer-scale microfactories, tactile robot skins, next generation energy storage (solar cells), nanostructure plasmonic devices, and biosensors. The NeXus has the flexibility to fixture, position, transport, and assemble components across a wide spectrum of length scales (Macro-Meso-Micro-Nano, 1m to 100nm) and provides unparalleled additive process capabilities such as 3D printing through both aerosol jetting and ultrasonic bonding and forming, thin-film photonic sintering, fiber loom weaving, and in-situ Micro-Electro-Mechanical System (MEMS) packaging and interconnect formation. The NeXus system has a footprint of around 4m x 3.5m x 2.4m (X-Y-Z) and includes two industrial robotic arms, precision positioners, multiple manipulation tools, and additive manufacturing processes and packaging capabilities. The design of the NeXus platform adopted the Lean Robotic Micromanufacturing (LRM) design principles and simulation tools to mitigate development risks. The NeXus has more than 50 degrees of freedom (DOF) from different instruments, precise evaluation of the custom robots and positioners is indispensable before employing them in complex and multiscale applications. The integration and control of multi-functional instruments is also a challenge in the NeXus system due to different communication protocols and compatibility. Thus, the NeXus system is controlled by National Instruments (NI) LabVIEW real-time operating system (RTOS) with NI PXI controller and a LabVIEW State Machine User Interface (SMUI) and was programmed considering the synchronization of various instruments and sequencing of additive manufacturing processes for different tasks. The operation sequences of each robot along with relevant tools must be organized in safe mode to avoid crashes and damage to tools during robots’ motions. This thesis also describes two demonstrators that are realized by the NeXus system in detail: skin tactile sensor arrays and electronic textiles. The fabrication process of the skin tactile sensor uses the automated manufacturing line in the NeXus with pattern design, precise calibration, synchronization of an Aerosol Jet printer, and a custom positioner. The fabrication process for electronic textiles is a combination of MEMS fabrication techniques in the cleanroom and the collaboration of multiple NeXus robots including two industrial robotic arms and a custom high-precision positioner for the deterministic alignment process

Positioning accuracy characterization of assembled microscale components for micro-optical benches

International audienceThis paper deals with the measurement of microscale components' positioning accuracies used in the assembly of Micro-Optical Benches (MOB). The concept of MOB is presented to explain how to build optical MEMS based on out-of-plane micro-assembly of microcomponents. The micro-assembly platform is then presented and used to successfully assemble MOB. This micro-assembly platform includes a laser sensor that enables the measure of the microcomponent's position after its assembly. The measurement set-up and procedure is displayed and applied on several micro-assembly sets. The measurement system provides results with a maximum deviation less than +/- 0.005°. Based on this measurement system and micro-assembly procedure, the article shows that it is possible to obtain a positioning errors down to 0.009°. These results clearly state that micro-assembly is a possible way to manufacture complex, heterogeneous and 3D optical MEMS with very good optical performances

White paper on the future of plasma science and technology in plastics and textiles

This is the peer reviewed version of the following article: “Uros, C., Walsh, J., Cernák, M., Labay, C., Canal, J.M., Canal, C. (2019) White paper on the future of plasma science and technology in plastics and textiles. Plasma processes and polymers, 16 1 which has been published in final form at [doi: 10.1002/ppap.201700228]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."This white paper considers the future of plasma science and technology related to the manufacturing and modifications of plastics and textiles, summarizing existing efforts and the current state‐of‐art for major topics related to plasma processing techniques. It draws on the frontier of plasma technologies in order to see beyond and identify the grand challenges which we face in the following 5–10 years. To progress and move the frontier forward, the paper highlights the major enabling technologies and topics related to the design of surfaces, coatings and materials with non‐equilibrium plasmas. The aim is to progress the field of plastics and textile production using advanced plasma processing as the key enabling technology which is environmentally friendly, cost efficient, and offers high‐speed processingPeer ReviewedPostprint (author's final draft

Micro-manufacturing research : drivers and latest developments (Keynote Paper)

Increased demands on micro-products and miniaturised systems/devices may have been a main driver to the rapid growth of the interest in research in micro- and nano-manufacturing. It seems, however, not to be the only reason why so much funding has been made available for researchers to be able to conduct research in this emerging field. A review was conducted recently with a view to gaining a clearer view of demands on the applications and on trends in developments in micro-manufacturing, by looking at the market, research topics, projects, interactions with industry, outcomes and applications. It was found that there have been significant changes/advances in micro-manufacturing research, compared to what had been undertaken and achieved in 5 ~ 10 years ago, being reflected especially by: (i). micro-manufacturing research bridging “nano-manufacturing” and “macro-manufacturing” and hence, bringing nano-technology into real-life and affordable products; (ii). addressing multi-length scale manufacturing problems and hence, linking it to macro-sized product manufacturing, which adds its relevance to general manufacturing and wide-sector applications; (iii). micro-manufacturing research being shifted from “process focus” to “market/product” driven research and technological development addressing production capability, product quality, pilot production line demonstration and delivery; and (iv). micro-manufacturing research playing roles in helping to transform traditional industry and products. These new developments may justify past and current significant investment in research and technological development in micro- and nano-manufacturing, and suggest more significant impacts to come in near future

Plasma sprayed titanium coatings with/without a shroud

Abstract: Titanium coatings were deposited by plasma spraying with and without a shroud. The titanium coatings were then assessed by scanning electron microscopy. A comparison in microstructure between titanium coatings with and without the shroud was carried out. The results showed that the shroud played an important role in protecting the titanium particles from oxidation. The presence of the shroud led to a reduction in coating porosity. The reduction in air entrainment with t he shroud resulted in better heating of the particles, and an enhanced microstructure with lower porosity in the shrouded titanium coatings were observed compared to the air plasma sprayed counterpart

Modular and Reconfigurable 3D Micro-Optical Benches : Concept, Validation and Characterization.

International audienceIn this paper, we present an approach to design MOEMS based on Reconfigurable Free Space Micro-Optical Benches (RFS-MOB). The proposed concept enables to design modular and reconfigurable MOEMS by using a generic structure of silicon holders and non defined position in the substrate. Various micro-optical elements, e.g. microlenses or micromirrors, can be integrated within holders. Their assembly is achieved with an active microgripper, after high precision alignement within guiding rails of silicon substrate. Flexible parts are used to maintain a final position. The concept is validated by successful assembly of holders. A characterization method of assembled holders is proposed and provides an accuracy better than 0.04 for an angle measurement

Agenda: Second International Workshop on Thin Films for Electronics, Electro-Optics, Energy and Sensors (TFE3S)

University of Dayton’s Center of Excellence for Thin Film Research and Surface Engineering (CETRASE) is delighted to organize its second international workshop at the University of Dayton’s Research Institute (UDRI) campus in Dayton, Ohio, USA. The purpose of the new workshop is to exchange technical knowledge and boost technical and educational collaboration activities within the thin film research community through our CETRASE and the UDRI

Surface Engineering for Phase Change Heat Transfer: A Review

Among numerous challenges to meet the rising global energy demand in a sustainable manner, improving phase change heat transfer has been at the forefront of engineering research for decades. The high heat transfer rates associated with phase change heat transfer are essential to energy and industry applications; but phase change is also inherently associated with poor thermodynamic efficiencies at low heat flux, and violent instabilities at high heat flux. Engineers have tried since the 1930's to fabricate solid surfaces that improve phase change heat transfer. The development of micro and nanotechnologies has made feasible the high-resolution control of surface texture and chemistry over length scales ranging from molecular levels to centimeters. This paper reviews the fabrication techniques available for metallic and silicon-based surfaces, considering sintered and polymeric coatings. The influence of such surfaces in multiphase processes of high practical interest, e.g., boiling, condensation, freezing, and the associated physical phenomena are reviewed. The case is made that while engineers are in principle able to manufacture surfaces with optimum nucleation or thermofluid transport characteristics, more theoretical and experimental efforts are needed to guide the design and cost-effective fabrication of surfaces that not only satisfy the existing technological needs, but also catalyze new discoveries