| 1. |
- Reinhold, Ingo, 1981-, et al.
(författare)
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A hybrid approach combining 3D and conductive inkjet printing for the generation of linear ion traps for mass spectrometry applications
- 2014
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Ingår i: International Conference on Digital Printing Technologies. - : Society for Imaging Science and Technology. ; , s. 133-136, s. 133-136
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Konferensbidrag (refereegranskat)abstract
- Printed conductors have attracted strong interest in academia as well as the industry. While first applications using printed conductors on flat as well as curved surfaces are establishing in the market, extensive research still is conducted on the postprocessing technologies needed for high-volume fabrication of solution processed conductors. With regards to the potential low-cost, high-throughput manufacturing of conductors on inexpensive polymeric foils, new applications start to evolve that call for an even more elaborate investigation of the printing and post-processing steps included. This paper assesses the potential of inkjet-printed conductors for the use in low-pressure environments, such as linear ion-traps for mass spectrometry. In these environments remainders of trapped air or organic solvents affect the performance and lifetime of the getter pump systems used. Additionally, high frequency characteristics of the processed conductors are investigated as these are essential for the sensitivity of an ion trap. In this contribution we establish the framework for the application of conductive Inkjet printing on curved surfaces for sensing application in low-pressure environments. Inkjet-deposited nanoparticle inks were investigated with respect to their characteristics under vacuum conditions. The deposits on polymeric foils as well as on DLP processed three-dimensional semi-finished parts were subjected to thermal post-processing and measured with respect to their electrical characteristics as well as their outgassing behavior.
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| 2. |
- Reinhold, Ingo, 1981-, et al.
(författare)
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Analysis of Formation of an Individual Droplet Using a High-ResolutionMulti-Exposure Imaging System
- 2013
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Ingår i: International Conference on Digital Printing Technologies and Digital Fabrication. ; , s. 354-358
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Konferensbidrag (refereegranskat)abstract
- Localized dispensing of precious functional materials has attracted considerable interest in the academic as well as the industrial society. While the number of publications show numerous fields of applications in printed electronics, photovoltaics, display technologies and thin functional coatings, the transition into the industrial sector is often hindered by challenges resulting from ink-printhead combinations and their implications on reliability and stability of the process, as well as side-effects such as mist accumulation in heavy duty printing equipment.While measuring equipment to quantify various rheological and interfacial parameters foor fluid optimization has been developed with the accompanying mathematical models, the physical jetting experiment as well as high-duty printing trials cannot yet be substituted by these methods. In order to quantify the generation of a droplet alongside with its tailing behavior and mist formation as well as statistics based on cross-talk effects and relaxation-related effects, high-resolution and high-speed imaging are required.This paper examines the optical setup and outlines the required calculations for establishing sharp, high-resolution images using a combination of a high power laser diode with a resonant MEMS micro mirror with a theoretical resolution of 1.8 μm. The limitations of the setup regarding the achievable resolution as well as potential improvements are assessed. Furthermore, the experimental setup, including repetitive generation of nanosecond-pulses necessary for motion-blur-free images, will be discussed. Additionally, results from imaging a droplet formation process using a Xaar 126 printhead are discussed.
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| 3. |
- Reinhold, Ingo, 1981-
(författare)
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Industrial Digital Fabrication Using Inkjet Technology
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The use of acoustic waves initiated by the deformation of a microchannel is one method for generating monodisperse, micrometer-sized droplets from small orifices and is employed in piezo-electric inkjet printheads. These printheads are used in both graphical printing and digital fabrication, where functionalities, such as optical, biological, electrical or mechanical, are being produced locally. The processes leading to detrimental artifacts such as satellite droplets or nozzle outages, however, are not fully understood and require profound experimentation. This thesis presents both novel techniques to study jetting for optimal droplet formation and reliability, as well as the post-processing techniques required for solution-based production of a conductive feature on low-cost polymeric substrates.A multi-exposure imaging system using laser light pulses shorter than 50 ns and a MEMS micro-mirror enabled the imaging of the droplet formation at ten instances on the droplet's travel towards the substrate. The technique allows for the study of droplet formation, satellite droplet break-up and secondary tail formation allowing for better control and understanding of the process.Reliability measurement using a linescan camera was introduced to record every droplet ejected from the width of a printhead. The variations in droplet velocity and misalignment of the printhead required the use of a constant background illumination to reliably capture the droplets. The resulting low-contrast images were post-processed using statistical analysis of the graylevel distributions of both, the droplet and background pixels, and were subsequently used in a histogram matching algorithm to enable reliable identification of the threshold value required for unhindered detection of missing droplets based on the printed image. Using temporal oversampling the technique was shown to qualitatively describe droplet velocity variations introduced by the actuation of the printhead. The conversion of inkjet-printed metallic nanoparticle inks to conductive structures was investigated with a focus on the applicability to industrial processes. Intense pulsed light (IPL) processing achieved comparable results to convective oven sintering in less than ten seconds. The dynamics of IPL sintering were found to be strongly dependent on the spectral composition of the light resonating in the processing chamber. By implementing a passive filtering concept, thermal runaway was prevented and the line conformation was optimized irrespective of the underlying substrate. Alternatively, pulse-shaping, to tailor the energy flux into the deposit and incorporate drying in the IPL process, was found to generate conductive copper features without pre-drying.The findings were applied to applications comprising small droplet generation for nanoimprint lithography, the fabrication of conductors for blind via connections to buried LED dies as well as the hybrid generation of hyperbolic ion-trap electrodes for mass spectrometry applications. The addition of the non-contact and high accuracy of the inkjet process enabled suitable performance that lies beyond that of conventional processes.
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| 4. |
- Reinhold, Ingo, 1981-, et al.
(författare)
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Quantitative Assessment of Inkjet Reliability under Industrial Conditions : Measuring All Drops during Extended High‐Duty Printing
- 2018
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Ingår i: Handbook of Industrial Inkjet Printing. - Weinheim : Wiley-VCH Verlagsgesellschaft. - 9783527338320 - 9783527687169 ; , s. 445-458
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Bokkapitel (refereegranskat)abstract
- Reliability is one of the key challenges in inkjet technology. Nozzles perform unreliably for a number of reasons, such as drying, clogging through air‐ and inkborne contaminants, ingestion of air, or nozzle plate flooding. To extract quantitative information about the number of missing droplets from the acquired images, suitable algorithms need to be applied. To identify the presence of the droplet, a value derived from the characteristics of the area of interest needs to be compared with the threshold value. The Line Scan approach for the measurement of reliability offers a convenient way to assess reliability of a printhead in a laboratory environment providing quantitative and statistical data about location, duration, and time of misfire events. With the knowledge of the printhead frequency and the hypothetical print resolution applied in the printing experiments, the length of such tic marks as a number of subsequent missing droplets can be calculated.
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| 5. |
- Zapka, Werner, et al.
(författare)
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Drucken jenseits der Farbe
- 2013
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Ingår i: Elektronik. - 0013-5658. ; :12, s. 34-39
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Tidskriftsartikel (refereegranskat)
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