Novel 3D manufacturing method combining microelectrial discharge machining and electrochemical polishing

Richter, Claudia; Krah, Thomas; Büttgenbach, S.

doi:10.1007/s00542-012-1452-x

Cited by 30 publications

(7 citation statements)

References 9 publications

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“…Homogenization of the pre‐emulsion was performed in a customized microchannel high‐pressure emulsification setup as described in previous work . In brief, the sample was processed three cycles at a pressure drop of 1250 bar through a consecutive double orifice microsystem (depth: 50 µm; orifice widths: 80 µm; orifice length: 300 µm; inter‐orifice distance: 5169 µm) made of stainless steel . Afterwards, the sample was allowed to cool to ambient conditions, if applicable.…”

Section: Methodsmentioning

confidence: 99%

Coumarin 6 as a fluorescent model drug: How to identify properties of lipid colloidal drug delivery systems via fluorescence spectroscopy?

Finke

Richter

Gothsch

et al. 2014

Euro J Lipid Sci & Tech

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In the development of colloidal lipid drug delivery systems (DDS), the localization of the drug within the DDS, the protective potential of the DDS as well as the compatibility of the drug with the excipients are of special interest. In this study, Coumarin 6 (C6), a fluorescent dye frequently used to facilitate the traceability of DDS in vitro, is demonstrated as a tool to gain insight into the aforementioned properties by fluorescence spectroscopy. Both ways of loading C6 to solid colloidal DDS (pre‐loading to the lipid matrix or post‐loading to the ready DDS after its processing) led to a localization of C6 in the interfacial layer between solid lipid nanoparticles (SLN) and aqueous medium. In the case of pre‐loading, C6 is homogenously distributed in emulsion droplets and expelled from the lipid matrix due to crystallization. Nanoemulsions distributed C6 in the liquid lipid matrix itself and cause a hypsochromic shift of fluorescence spectra. Larger surface areas of emulsion droplets due to smaller droplet sizes displayed more interaction of C6 with the aqueous phase as a bathochromic shoulder in fluorescence spectra. Measured fluorescence intensity was linearly dependent on light scattering of colloidal DDS of the same excipients. A simple method to evaluate the protective properties of DDS was presented and displayed that (i) nanoemulsions provide more protection compared with SLN and (ii) higher phospholipid concentration improve the protection within SLN. Practical applications: In the development of colloidal DDS, it is important to identify the localization and distribution of a (model) drug in compartments within the disperse system. The simple approach by fluorescence spectroscopy presented in this study supplies information about the localization of drug substances with properties comparable with the fluorescent probe used. The results assist formulation development as a quick screening tool to elucidate (i) the localization of the probe, (ii) the microenvironment of the probe (e.g., differentiation of the physical state of the disperse phase), and (iii) the protection of the probe against damaging agents from the aqueous phase. The fluorescent dye Coumarin 6 was applied as model drug in colloidal lipid drug delivery systems. Fluorescence spectroscopy proved able to identify the localization of the model compound, the physical state of the dispersed phase, and the protective potential of the DDS, especially dependent on phospholipid concentration.

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Section: Methodsmentioning

confidence: 99%

Coumarin 6 as a fluorescent model drug: How to identify properties of lipid colloidal drug delivery systems via fluorescence spectroscopy?

Finke

Richter

Gothsch

et al. 2014

Euro J Lipid Sci & Tech

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“…Styli with ruby spheres of diameters between 300 µm and 120 µm are commercially available. Styli with tips down to 50 µm diameter can be produced using wire electro-discharge grinding (using SX200 from Sarix) as detailed in [23,29].…”

Section: Fabrication and Assemblymentioning

confidence: 99%

“…The combination of a microprobe and a GMI has made possible for measuring geometries with a small tip diameter down to 50 µm [23,29]. In the first part of this work, the microprobe, its working principle, its production and its new assembly, and its properties are presented.…”

Section: Introductionmentioning

confidence: 99%

Integration of a piezoresistive microprobe into a commercial gear measuring instrument

Metz

Ferreira

Chaillot

et al. 2019

Precision Engineering

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Various microprobes have been developed in the last decade to address the needs of micrometrology. However, most microprobes are only employed in specialized measuring machines located in a few research institutes and are not widespread in the industry. This work aims to extend the capabilities of conventional coordinate measuring machines (CMMs) towards measuring microgeometries through the low-cost integration of a tactile microprobe. In order to demonstrate this, a gear measuring instrument (GMI), which is a commercial CMM not specialized for measurements at the microscale, has been equipped with a recently developed silicon-membrane-based microprobe. In the first part of this work, the working principle of the microprobe, its assembly and its integration into the GMI are described. Two different mounting setups of the microprobe onto the GMI were evaluated and tested. Measurements on the GMI were performed solely with the microprobe or by combining the microprobe and the measurement system already present on the GMI. This combination makes it possible to use the microprobe advantageously and to exchange it in a comfortable semi-automatic way. To test these two mounting setups, a new involute scanning artifact (SAFT) with superimposed waviness was measured.

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“…Micro-EDM has small macro cutting force and can process a variety of super-hard and brittle material. Due to these advantages, scholars have applied micro-EDM for processing 3D micro-cavity molds [1][2][3], micro-parts [4][5][6], and micro-holes [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Laminated fabrication of 3D queue micro-electrode and its application in micro-EDM

Lei

Cheng

et al. 2015

Int J Adv Manuf Technol

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3D micro-electrode used in micro electrical discharge machining (micro-EDM) is difficult to be fabricated. Based on laminated object manufacturing (LOM) process, this paper superimposed multilayer 2D micro-structures together to fit out 3D micro-electrode and applied it in micro-EDM to process 3D micro-cavity mold. Firstly, 100-μm-thick Cu foils were cut by wire-electrical discharge machining (WEDM) to obtain multilayer 2D micro-structures, and then these 2D micro-structures were connected together to fit out 3D micro-electrode through vacuum pressure thermal diffusion welding. Secondly, under the effect of 80-V voltage, 0.2-MHz pulse frequency, 800-ns pulse width, and 4200-ns pulse interval, the 3D micro-electrode was applied in micro-EDM and 3D micro-cavity mold with high surface quality was obtained. Thirdly, in order to reduce the adverse impact of electrode wear on machining precision of 3D micro-cavity mold, 3D queue micro-electrode was used to process the same 3D micro-cavity mold, in which the first electrode is for rough machining and the others for fine machining. Finally, based on the above studies, two kinds of 3D queue micro-electrodes were fabricated, and the 3D micro-cavity molds with surface roughness Ra=0.48 μm were obtained through micro-EDM. Compared with the scanning 3D micro-EDM process, the 3D micro-cavity mold can be obtained through up and down reciprocating method of the 3D queue micro-electrode, featuring simple machining process and high efficiency.

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Novel 3D manufacturing method combining microelectrial discharge machining and electrochemical polishing

Cited by 30 publications

References 9 publications

Coumarin 6 as a fluorescent model drug: How to identify properties of lipid colloidal drug delivery systems via fluorescence spectroscopy?

Coumarin 6 as a fluorescent model drug: How to identify properties of lipid colloidal drug delivery systems via fluorescence spectroscopy?

Integration of a piezoresistive microprobe into a commercial gear measuring instrument

Laminated fabrication of 3D queue micro-electrode and its application in micro-EDM

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