Received: 1 March 2021 Revised: 9 August 2021 Accepted: 5 November 2021 DOI: 10.1002/pts.2619
RESEARCH ARTICLE
Tray forming operation of paperboard: A case study using implicit finite element analysis
Gustav Lindberg | Artem Kulachenko
Solid Mechanics, Department of Engineering Mechanics, Royal Institute of Technology, Stockholm, Sweden Correspondence Gustav Lindberg, Solid Mechanics, Department of Engineering Mechanics, Royal Institute of Technology, Stockholm, Sweden. Email: gulindbe@kth.se
Abstract The possibility to perform advanced forming operations of initially plane paperboard paves the way to making products like food trays, plates, cups and other containers as a part of shifting towards a circular bioeconomy. As a part of the ongoing efforts of expanding the product range using paperboard, we performed analyses of the for- ming operation using simulations. An implicit non-linear finite element model is built to more accurately than previous studies simulate the tray forming process of paper- board. Two different commercial paperboards are investigated. The use of an implicit solver enabled the inclusion of the creasing pattern into the geometry of the paper- board blank resolving the formation of wrinkles during forming. The material data is extracted from tensile test curves of the investigated paperboards and was fitted accurately using Hill's plasticity with difference in tension and compression accounted for with subsequent failure evaluation. The results showed that the inclu- sion of the creases in the geometry is vital for getting a correct shape of the formed tray and important for decreasing the risk of failure. The results also showed that fric- tion has a big impact on the formed shape and hence on the stress levels, and there- fore supports the means of lowering friction between the blank holder and the blank during the tray forming operation. A stochastic approach is proposed to determine the probability of failure for the boards. The performed failure evaluation is consis- tent with the field observations. The developed approach enables more precise simu- lations of paperboard tray forming.
Funding information Swedish National Infrastructure for Computing
(SNIC), Grant/Award Number: SNIC 2020/5-428 and SNIC 2021/6-51
KEYWORDS creases, Hill's plasticity, non-linear finite elements, paperboard, tray forming
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INTRODUCTION
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time, paperboard is an important part of shifting towards a circular bioeconomy and the effort to increase formability and the processes enabling the forming operation is ongoing. There are several types of forming operations for paperboard, such as hydroforming, press (tray) forming, deep drawing and molding. The first three of them are all variants of pressing down a sheet of paper or paperboard, called the blank, into a die. Hydroforming pres- ses the blank downwards utilizing air pressure. The press forming uses
Today, the possibility to perform advanced forming operations of paperboard has a big interest in the industry to create products like food trays, plates, cups and other containers. 1 – 3 However, compared to plastics and sheet metal, paperboard has lower formability. Deep drawing of sheet metal is widely used in many industries, 4 – 6 and plas- tics are used to form a variety of trays and containers. 7,8 At the same
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2021 The Authors. Packaging Technology and Science published by John Wiley & Sons Ltd.
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Packag Technol Sci. 2021;1 – 16.
wileyonlinelibrary.com/journal/pts
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