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The Global ETD Search service is a free service for researchers
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Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Showing 1 to 10 of 14 (0.068 seconds)| 1 |
Super-stretchable paper-based materials for 3D formingKhakalo, Alexey, Kouko, Jarmo, Retulainen, Elias, Rojas, Orlando J. 30 May 2018 (has links)
Paper is renewable, recyclable, sustainable and biodegradable material and, as a result, paper-based materials are widely used in the world packaging market. However, paper-based materials cannot compete with plastics in terms of processability into various 3D shapes. This is due to poor formability of paper, which is closely associated with its toughness. To improve paper formability, we report on a facile and green method that combines fiber and paper mechanical modifications at different structural levels as well as biopolymer treatment via spraying. As a result, a remarkable elongation of ∼30% was achieved after proposed combined approach on the laboratory scale. At the same time, a significant increase in tensile strength and stiffness (by ∼306% and ∼690%, respectively) was observed. Overall, an inexpensive, green, and scalable approach is introduced to improve formability of fiber networks that in turn allows preparation of 3D shapes in the processes with fixed paper blanks such as vacuum forming, hydroforming, hot pressing, etc.
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Gastight Paperboard PackageHauptmann, Marek, Schult, Andre, Zelm, Roland, Gailat, Tilo, Lenske, Alexander, Majschak, Jens-Peter, Großmann, Harald 28 October 2013 (has links) (PDF)
Packages made from coated paperboard are currently used in food packaging for frosted or microwave food. These cups are usually deep drawn from flat paperboard blanks. The blanks are pre-creased to control the material overflow that appears during drawing. The resulting wrinkles in the sealing area have to be considered as capillary tubes allowing the gas exchange between the package and the environmental atmosphere. A new technological approach in 3D forming enables the prevention of capillary tubes in the sealing area. The result is a gas-tight sealable paperboard cup which is limited by its coating concerning the degree of gas tightness.
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Super-stretchable paper-based materials for 3D formingKhakalo, Alexey, Kouko, Jarmo, Retulainen, Elias, Rojas, Orlando J. 30 May 2018 (has links) (PDF)
Paper is renewable, recyclable, sustainable and biodegradable material and, as a result, paper-based materials are widely used in the world packaging market. However, paper-based materials cannot compete with plastics in terms of processability into various 3D shapes. This is due to poor formability of paper, which is closely associated with its toughness. To improve paper formability, we report on a facile and green method that combines fiber and paper mechanical modifications at different structural levels as well as biopolymer treatment via spraying. As a result, a remarkable elongation of ∼30% was achieved after proposed combined approach on the laboratory scale. At the same time, a significant increase in tensile strength and stiffness (by ∼306% and ∼690%, respectively) was observed. Overall, an inexpensive, green, and scalable approach is introduced to improve formability of fiber networks that in turn allows preparation of 3D shapes in the processes with fixed paper blanks such as vacuum forming, hydroforming, hot pressing, etc.
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Advances on Geometrical Limits in the Deep Drawing Process of PaperboardHauptmann, Marek, Kaulfürst, Sebastian, Majschak, Jens-Peter 06 September 2018 (has links)
The geometrical limits of the deep drawing process of paper to advanced shapes are not known. This report examines the technological limits of convex elements of the base shape in relation to the drawing height and shows the material behavior in the bottom radius of 3D shapes with regard to special material properties. In the bottom radius, non-compressed wrinkles occurred due to the in-plane compression, but wrinkles were reduced by an increased blank holder force or tool temperatures and improved extensibility or in-plane compressive strain. The forming ratio during deep drawing (drawing height related to base diameter) was increased to a value of more than 1 by a blank holder force, which increased with the drawing height such that the initial blank holder force was reduced concurrently. Straight sections in the base shape reduced the risk for ruptures in the edge radii of rectangular shapes, producing a forming ratio in these radii of 2.5. The forming ratio was further supported by a pattern of creasing lines at the blanks with a radial orientation and a number near the expected maximum number of wrinkles. The spring-back at rectangular shapes mainly depended on the drawing height and edge radius.
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Neue Einsatzpotentiale naturfaserbasierter Materialien in der Konsumgüterproduktion durch die technologische Entwicklung des Ziehverfahrens am Beispiel der Verpackung / New application potential of biofibre-based materials in the production of consumer goods by technological development of the deep drawing process on the example of packagingHauptmann, Marek 11 July 2017 (has links)
Die Produktion verschiedener Arten von Gütern ist im globalen Kontext gesellschaftlicher Entwicklung fortwährend an die Verfügbarkeit von Ressourcen gebunden und durch diese zunehmend begrenzt. In den bis heute entstandenen Wertschöpfungsketten basiert die verlustarme und effiziente Verteilung von Produkten, Zwischenprodukten, Halbzeugen sowie auch Rohstoffen auf den spezifisch auf die jeweiligen Erfordernisse eingestellten Funktionen ihrer Verpackungen. Als Bindeglied in nahezu allen Teilen der Produktion werden die Verpackung und ihre Herstellung innerhalb des mit Abstand größten Teils ihrer Anwendung, den Konsumgüterverpackungen als Beispiel für die Diskussion von Einsatzpotentialen naturfaserbasierter Materialien verwendet. Die Habilitationsschrift stellt die Ausgangssituation in der weltweiten Konsumgüterproduktion und Ressourcenverfügbarkeit dar und ordnet die Position naturfaserbasierter Packmittel in diese ein. Es werden Technologien zur Formgebung naturfaserbasierter Materialien zu Packmitteln zusammenfassend dargestellt. Die Ziehtechnik wird im Speziellen in Form eines Leitfadens in ihren Wirkmechanismen und Prozessvarianten sowie in Bezug auf ihre technische Umsetzung dargestellt. Es werden Beispiele konkreter Anwendungsmöglichkeiten diskutiert.
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Neue Einsatzpotentiale naturfaserbasierter Materialien in der Konsumgüterproduktion durch die technologische Entwicklung des Ziehverfahrens am Beispiel der Verpackung / New application potential of biofibre-based materials in the production of consumer goods by technological development of the deep drawing process on the example of packagingHauptmann, Marek 23 August 2017 (has links) (PDF)
Die Produktion verschiedener Arten von Gütern ist im globalen Kontext gesellschaftlicher Entwicklung fortwährend an die Verfügbarkeit von Ressourcen gebunden und durch diese zunehmend begrenzt. In den bis heute entstandenen Wertschöpfungsketten basiert die verlustarme und effiziente Verteilung von Produkten, Zwischenprodukten, Halbzeugen sowie auch Rohstoffen auf den spezifisch auf die jeweiligen Erfordernisse eingestellten Funktionen ihrer Verpackungen. Als Bindeglied in nahezu allen Teilen der Produktion werden die Verpackung und ihre Herstellung innerhalb des mit Abstand größten Teils ihrer Anwendung, den Konsumgüterverpackungen als Beispiel für die Diskussion von Einsatzpotentialen naturfaserbasierter Materialien verwendet. Die Habilitationsschrift stellt die Ausgangssituation in der weltweiten Konsumgüterproduktion und Ressourcenverfügbarkeit dar und ordnet die Position naturfaserbasierter Packmittel in diese ein. Es werden Technologien zur Formgebung naturfaserbasierter Materialien zu Packmitteln zusammenfassend dargestellt. Die Ziehtechnik wird im Speziellen in Form eines Leitfadens in ihren Wirkmechanismen und Prozessvarianten sowie in Bezug auf ihre technische Umsetzung dargestellt. Es werden Beispiele konkreter Anwendungsmöglichkeiten diskutiert.
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Gastight Paperboard Package: A new Step in Food PackagingHauptmann, Marek, Schult, Andre, Zelm, Roland, Gailat, Tilo, Lenske, Alexander, Majschak, Jens-Peter, Großmann, Harald January 2013 (has links)
Packages made from coated paperboard are currently used in food packaging for frosted or microwave food. These cups are usually deep drawn from flat paperboard blanks. The blanks are pre-creased to control the material overflow that appears during drawing. The resulting wrinkles in the sealing area have to be considered as capillary tubes allowing the gas exchange between the package and the environmental atmosphere. A new technological approach in 3D forming enables the prevention of capillary tubes in the sealing area. The result is a gas-tight sealable paperboard cup which is limited by its coating concerning the degree of gas tightness.
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Characterization of Influences on the Wall Stability of Deep Drawn Paperboard ShapesHauptmann, Marek, Majschak, Jens-Peter 08 June 2016 (has links) (PDF)
Deep drawn shapes with orthogonal wall components are usually evaluated by shape accuracy and visual quality. There have been only a few investigations on the stability of such structures; however, the effect of the wrinkles on the stability of the wall is important for packaging applications and can support the shape accuracy. This paper focuses on the influences of process parameters on the stability of orthogonal walls of shapes produced by deep drawing with rigid tools and immediate compression. The wall stability was evaluated by tensile testing orthogonal to the direction of the wrinkles. The stability distribution was characterized with regard to the drawing height, and a comparison was made between the two different materials. The wall stability decreased with increases in the forming height. Furthermore, a blank holder force design and z-directional compression level improved the wall stability. Together with an elevated moisture content of the material and thermal energy supply that delivered two to three times higher resistance against wrinkle extension, these effects drastically improved the wall stability.
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Evaluating the Factors Influencing the Friction Behavior of Paperboard during the Deep Drawing ProcessLenske, Alexander, Müller, Tobias, Penter, Lars, Schneider, Matti, Hauptmann, Marek, Majschak, Jens-Peter 28 June 2018 (has links) (PDF)
Deep drawing of paperboard with rigid tools and immediate compression has only a small presence in the market for secondary packaging solutions due to a lack of understanding of the physical relations that occur during the forming process. As with other processes that deal with interactions between two solids in contact, the control of the factors that affect friction is important due to friction’s impact on runnability and process reliability. A new friction measurement device was developed to evaluate the factors influencing the friction behavior of paperboard such as under the specific conditions of the deep drawing process, which differ from the standard friction testing methods. The tribocharging of the contacting surfaces, generated during sliding friction, was determined to be a major influence on the dynamic coefficient of friction between paperboard and metal. The same effect could be examined during the deep drawing process. With increased contact temperature due to the heating of the tools, the coefficient of friction decreased significantly, but it remained constant after reaching a certain charging state after several repetitions. Consequently, to avoid ruptures of the wall during the forming process, tools that are in contact with the paperboard should be heated.
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Characterization of Influences on the Wall Stability of Deep Drawn Paperboard ShapesHauptmann, Marek, Majschak, Jens-Peter 08 June 2016 (has links)
Deep drawn shapes with orthogonal wall components are usually evaluated by shape accuracy and visual quality. There have been only a few investigations on the stability of such structures; however, the effect of the wrinkles on the stability of the wall is important for packaging applications and can support the shape accuracy. This paper focuses on the influences of process parameters on the stability of orthogonal walls of shapes produced by deep drawing with rigid tools and immediate compression. The wall stability was evaluated by tensile testing orthogonal to the direction of the wrinkles. The stability distribution was characterized with regard to the drawing height, and a comparison was made between the two different materials. The wall stability decreased with increases in the forming height. Furthermore, a blank holder force design and z-directional compression level improved the wall stability. Together with an elevated moisture content of the material and thermal energy supply that delivered two to three times higher resistance against wrinkle extension, these effects drastically improved the wall stability.
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