| People | Locations | Statistics |
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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Grunwald, Tim
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (16/16 displayed)
- 2024Friction in glass forming: Tribological behaviors of optical glasses and uncoated steel near glass transition temperaturecitations
- 2023Machine learning-based predictions of form accuracy for curved thin glass by vacuum assisted hot forming processcitations
- 2023Variationskraftgeregeltes 5-Achs-Schleifen ; The variation force-controlled finishing of curved tool steel surfaces with mounted points
- 2022Mold protective coatings for precision glass molding
- 2022Simulation of the Refractive Index Variation and Validation of the Form Deviation in Precisely Molded Chalcogenide Glass Lenses (IRG 26) Considering the Stress and Structure Relaxationcitations
- 2022Simulation of the Refractive Index Variation and Validation of the Form Deviation in Precisely Molded Chalcogenide Glass Lenses (IRG 26) Considering the Stress and Structure Relaxationcitations
- 2022Enabling Sustainability in Glass Optics Manufacturing by Wafer Scale Molding
- 2022Modeling nonequilibrium thermoviscoelastic material behaviors of glass in nonisothermal glass moldingcitations
- 2021Machine learning-based predictive modeling of contact heat transfercitations
- 2020Modeling of thermo-viscoelastic material behavior of glass over a wide temperature range in glass compression moldingcitations
- 2020Thermo-viscoelastic modeling of nonequilibrium material behavior of glass in nonisothermal glass moldingcitations
- 2020Precision Glass Molding of infrared optics with anti-reflective microstructurescitations
- 2019Experimental investigation of contact heat transfer coefficients in nonisothermal glass molding by infrared thermographycitations
- 2019Approaches and Methodologies for Process Development of Thin Glass Formingcitations
- 2019Molded anti-reflective structures of chalcogenide glasses for infrared optics by precision glass moldingcitations
- 2018Scalability of the precision glass molding process for an efficient optics productioncitations
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article
Experimental investigation of contact heat transfer coefficients in nonisothermal glass molding by infrared thermography
Abstract
Nonisothermal glass molding has recently become a promising technology solution for the cost‐efficient production of complex precision glass optical components. During the molding process, the glass temperature and its temperature distribution have crucial effects on the accuracy of molded optics. In nonisothermal molding, the glass temperature is greatly influenced by thermal contact conductance because there is a large temperature difference between the glass and mold parts. Though widely agreed to be varied during the molding process, the contact conductance was usually assumed as constant coefficients in most early works without sufficient experimental justifications. This paper presents an experiment approach to determine the thermal contact coefficient derived from transient temperature measurements by using infrared thermographic camera. The transient method demonstrates a beneficially short processing time and the adequate measurement at desirable molding temperature without glass sticking. Particularly, this method promises the avoidance of the overestimated contact coefficients derived from steady‐state approach due to the viscoelastic deformation of glass during the inevitably long period of holding force. Based on this method, the dependency of thermal contact conductance on mold surface roughness, contact pressure, and interfacial temperature ranging from slightly below‐to‐above glass transition temperature was investigated. The results reveal the dominance of interfacial temperature on the contact conductance while the linear pressure‐dependent conductance with an identical slope observed for all roughness and mold temperatures. The accurate determination of the contact heat transfer coefficients will eventually improve the predictions of the form accuracy, the optical properties, and possible defects such as chill ripples or glass breakage of molded lenses by the nonisothermal glass molding process