Paper Technology International 2024 - Journal - Page 43
PAPERTECHNOLOGYINTERNATIONAL
P
Prediction models for paper
processing and usage behavior
based on material properties
Toma Schneider, (Project Manager Methods & Simulation at Papiertechnische Stiftung)
Dr. Martin Zahel, (Head of Division Fibres & Composites at Papiertechnische Stiftung)
Benjamin Hiller, (Project Manager Methods & Simulation at Papiertechnische Stiftung)
INTRODUCTION:
In recent years, several methods have been increasingly used to analyze natural 昀椀ber-based materials with regard to their
processing properties and behavior in use. These include the 昀椀nite element method as well as methods based on automated machine
learning using arti昀椀cial neural networks. All of these methods make it possible to investigate the loads acting on the materials and draw
conclusions from them in order to develop improved processes and products. Time-consuming and cost-intensive tests at prototype level
can be reduced and developments can be implemented more ef昀椀ciently. The following three examples of recent research work at PTS will
explain application oriented opportunities in more detail:
Flexibilization of Hexagonal Honeycomb Cores
and Production of Double-Curved Honeycomb
Moulded Parts
The use of lightweight construction principles
in the mobility sector enables resources to be
conserved during production and use. A distinction
must be made between the use of materials and
energy to generate the structures and the use of
energy for movement during use and recycling, in
the sense of the circular economy. Due to their low
density, 昀氀at, closed lightweight components usually
also have low thermal conductivity, which enables
thermal insulation in addition to the enveloping and
supporting function. The combination of shell and
honeycomb construction is a possibility for realizing
advantageous lightweight structures, but requires
a curvature capacity of the component elements.
Thus the subject of a ZIM R&D cooperation project
“2k WaFo” was the realization of multi-curved
lightweight construction elements based on the
innovative FlexCore process.
Honeycomb core panels are a widespread
lightweight construction application, but until now
only 昀氀at geometries have been available in the
medium and lower price segments. This is due to
the fact that specially mouldable honeycomb cores are required to
generate curved components, which are considerably more complex
and therefore more cost-intensive in production than conventional
hexagonal honeycomb cores, for example. Based on this situation,
a process for producing mouldable honeycomb cores from virtually
endless honeycomb cores was developed at TU Dresden. Several
challenges were identi昀椀ed and cooperatively solved within the
research project in order to achieve the operational maturity of novel
honeycomb moulded parts based on hexagonal honeycomb cores.
The various project objectives, such as reproducible 昀氀exibilization,
material conservation, ef昀椀cient joining process, process prediction
and process monitoring, were distributed among the project partners
SmartPac Verpackungsmaschinen GmbH (SmartPac, machine
manufacturer), Deutsche Werkstätten Hellerau GmbH (DWH, 昀椀rst
user) as well as the Chair of Wood Technology and Fibre Materials
Figure 1: Flexibilizing element with aluminium honeycomb core.
Engineering at TU Dresden (HFT, project coordination and process
development) and the Papiertechnische Stiftung (PTS, process
prediction and optimization).
The existing FlexCore process for the production of
mouldable honeycomb cores was improved in several details by
HFT, expanded to include block processing and implemented in
the form of a format-昀氀exible forming unit by the project partner
SmartPac (detail in Fig. 1). An ef昀椀cient manufacturing process for
single and double-curved honeycomb moulded parts was developed
and successfully implemented by HFT and DWH for the honeycomb
cores 昀氀exibilized in this way (see Fig. 2 overleaf). Alongside the
process development, various prediction models were developed at
PTS.
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