Accepted Manuscripts

Vahid Nasrollahi, Pavel Penchev, Stefan Dimov, Lars Korner, Richard Leach and Kyunghan Kim
J. Micro Nano-Manuf   doi: 10.1115/1.4037645
Laser micro processing is a very attractive option for a growing number of industrial applications due to its intrinsic characteristics, such as high flexibility and process control and also capabilities for non-contact processing of a wide range of materials. However, there are some constrains that limit the applications of this technology, i.e. taper angles on side walls, edge quality, geometrical accuracy and achievable aspect ratios of produced structures. To address these process limitations a new method for two-side laser processing is proposed in this research. The method is described with a special focus on key enabling technologies for achieving high accuracy and repeatability in two-side laser drilling. The pilot implementation of the proposed processing configuration and technologies is discussed together with an in-process inspection procedure to verify the achievable positional and geometrical accuracy. It is demonstrated that alignment accuracy better than 10 µm is achievable using this pilot two-side laser processing platform. In addition, the morphology of holes with circular and square cross-sections produced with one-side laser drilling and the proposed method was compared in regards to achievable aspect ratios and holes' dimensional and geometrical accuracy and thus to make conclusions about its capabilities.
Yifei Jin, Danyang Zhao and Yong Huang
J. Micro Nano-Manuf   doi: 10.1115/1.4037646
Multi-layered encapsulation has been of great interest for various pharmaceutical, chemical and food industries. Fabrication of well-defined capsules with more than one shell layer still poses a significant fabrication challenge. This study aims to investigate the feasibility of using a coaxial nozzle to fabricate double-layered (core-shell-shell) capsules during vibration-assisted dripping. A three-layered coaxial nozzle has been designed, manufactured, and tested for double-layered capsule fabrication when using sodium alginate solutions as the model liquid material for inner and outer shell layers and calcium chloride solution as the core fluid. To facilitate the droplet formation process, a vibrator has been integrated into the fabrication system to provide necessary perturbation for effective breakup of the fluid flow. It is demonstrated that double-layered alginate capsules can be successfully fabricated using the proposed three-layered coaxial nozzle fabrication system. During fabrication, increasing the core flow rate leads to an increase in capsule and core diameters while the inner and outer shell layer thicknesses decrease. Increasing annular flow rate results in an increase in capsule diameter and inner shell layer thickness while the outer shell layer thickness decreases. An increase in the sheath flow rate leads to an increase in capsule diameter and outer shell layer thickness but has no significant effect on the core diameter and inner shell layer thickness.
Robert Altman, James F. Nowak and Johnson Samuel
J. Micro Nano-Manuf   doi: 10.1115/1.4037574
This paper is focused on developing an in-process intervention technique that mitigates the effect of built-up edges (BUEs) during micro-milling of aluminum. The technique relies on the intermittent removal of the BUEs formed during the machining process. This is achieved using a three-stage intervention that consists first of the mechanical removal of meso-scale BUEs, followed by an abrasive slurry treatment to remove the micro-scale BUEs. Finally, the tool is cleaned using a non-woven fibrous mat to remove the slurry debris. An on-machine implementation of this intervention technique is demonstrated, followed by a study of its influence on key micro-machining outcomes such as tool wear, cutting forces, part geometry, and burr formation. In general, all relevant machining measures are found to improve significantly with the intervention. The key attributes of this intervention that makes it viable for micro-machining processes include: (i) An experimental setup that can be implemented within the working volume of the micro-scale machine tool; (ii) No removal of the tool from the spindle, which ensures that the intervention does not change critical process parameters such as tool runout and offset values; and (iii) Implementation in the form of canned G-code subroutines dispersed within the regular micro-machining operation.
Technical Brief  
Maxym Rukosuyev, Syed Baqar and Martin Jun
J. Micro Nano-Manuf   doi: 10.1115/1.4037473
The importance of coatings in modern science and industry is great and the system presented in this manuscript attempts to provide a method of creating high quality nanoparticle coatings with in situ sintering of nanoparticles. Dual regime nozzle creates close to optimum conditions for particle delivery and deposition and the addition of in situ thermally assisted coating makes it more productive. Preliminary results show systems uniform coating and in situ sintering capability.
TOPICS: Coatings, Nanoparticles, Flames, Sintering, Nozzles, Particulate matter
Ciarán M. Maguire, Katherine Sillence, Matthias Roesslein, Claire Hannell, Guillaume Suarez, Jean-Jacques Sauvain, Sonja Capracotta, Servane Contal, Sebastien Cambier, Naouale El Yamani, Maria Dusinska, Agnieszka Dybowska, Antje Vennemann, Laura Cooke, Andrea Haase, Andreas Luch, Martin Wiemann, Arno Gutleb, Rafi Korenstein, Michael Riediker, Peter Wick, Patrick Hole and Adriele Prina-Mello
J. Micro Nano-Manuf   doi: 10.1115/1.4037124
One of the greatest challenges in the manufacturing and development of nanotechnologies is the requirement for robust, reliable and accurate characterization data. Presented here are the results of an interlaboratory comparison brought about through multiple rounds of engagement with NanoSight Malvern and 10 pan-European research facilities. Following refinement of the Nanoparticle Tracking Analysis technique, the size and concentration characterization of nanoparticles in liquid suspension was proven to be robust and reproducible for multiple sample types in mono-modal, binary or multi-modal mixtures. The limits of measurement were shown to exceed the 30 nm to 600 nm range (with all system models), with percentage coefficients of variation being calculated as sub 5 % for monodisperse samples. Particle size distributions were also improved through the incorporation of the Finite Track Length Adjustment algorithm, which most noticeably acts to improve the resolution of multimodal sample mixtures. The addition of a software correction to account for variations between instruments also dramatically increased the accuracy and reproducibility of concentration measurements. When combined, the advances brought about during the ILCs allow for the simultaneous determination of accurate and precise nanoparticle sizing and concentration data in one measurement.
TOPICS: Nanoparticles, Algorithms, Instrumentation, Nanotechnology, Computer software, Particle size, Manufacturing, Resolution (Optics)

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