A1 Journal article (refereed), original research

Surface Fracture Prevention in Paperboard Press Forming with Advanced Force Control


Open Access publication

Publication Details
Authors: Tanninen Panu, Leminen Ville, Pesonen Antti, Matthews Sami, Varis Juha
Publisher: Elsevier: Creative Commons Attribution Non-Commercial No-Derivatives License
Publication year: 2020
Language: English
Related Journal or Series Information: Procedia Manufacturing
Volume number: 47
Start page: 80
End page: 84
Number of pages: 5
ISSN: 2351-9789
JUFO-Level of this publication: 1
Open Access: Open Access publication

Abstract

Press forming is a
three-dimensional forming process used for industrial converting of
large quantities of fibre-based composite materials such as barrier
coated paperboard. The technology enables the production of plate and
tray packages of such high quality that it is possible to lid seal them
to create a gas-tight package. The method is primarily based on the
controlled folding and compression of materials using high forming
forces and elevated tool temperatures.

The corner
of the container is folded utilizing creases and a certain amount of
force is needed to achieve the desired result. Sliding of the package
blank is restrained with blank holding force which defines the overall
forming force. The magnitude of blank holding force is determined by the
shape and dimensions of the package and the properties of the material
to be moulded.

In some cases, the force optimized
to produce high-quality packages will cause fractures, which are only on
the surface layer of the paperboard, at corners of the tray. The
packaging is still fully functional, but the visual disadvantage makes
it look defective. The phenomenon is accentuated in converting of
printed paperboard, where the potentially brittle surface layer breaks
more easily and the colour difference makes the fractures eye-catching.

This
study investigated how by adjusting the blank holding force, paperboard
surface layer breakage can be prevented during processing. Various
ramps were programmed to control the forming cycle, which changed the
magnitude of the force during the pressing stroke. The results show that
there is no need to compromise the quality of the package as long as
the average magnitude of the blank holding force is maintained. If the
strength properties of the material to be formed are not sufficient to
apply a constant blank holding force, by reducing the force slightly at
certain points in the process cycle, material damage can be reduced or
prevented completely.


Last updated on 2020-10-08 at 10:51

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