Projects and research

The most important processing methods in the plastics industry are injection moulding and extrusion. However, when it comes to producing long, narrow and structured components, both technologies have decisive disadvantages: In injection moulding, the clamping platens limit the component length. The pressure required for filling also increases proportionally with the flow path length. This means that the technical limits of the injection moulding machine are quickly reached, especially with highly viscous moulding compounds (e.g. elastomer compounds). In the extrusion of elastomers, there is no mould constraint during vulcanisation. Extruded sealing profiles therefore usually have a lower dimensional stability. Furthermore, only comparatively simple sealing geometries can be extruded without assembly elements.

Within the framework of the FFG Bridge project RubExject II (duration 2016 - 2019), existing limits of elastomer processing are overcome based on the patented Exjection® technology and the advantages of both processing methods are combined. The process concept of the Exjection® technology is based on a cavity moulded into a sliding carriage. During the injection process, the cavity is moved perpendicular to the injection unit at a speed adapted to the flow front. With long, narrow components, this considerably reduces the injection pressure at the injection moulding machine.

For the first time, an Exjection® research mould specially designed for rubber compounds has been
has been developed. This allows possible process variants, including their process windows, as well as component and surface quality to be investigated in detail, thus laying the foundation for the injection moulding of very large, functionally integrated and at the same time cost-effective sealing profiles (e.g.: for wind turbines). 

At a glance

Funding: FFG Bridge
Project partners: IB Steiner, SKF Sealing Solutions Austria GmbH, ELMET Elastomere Produktions- und Dienstleistungs-GmbH

Contact
DI DI Sebastian Stieger
sebastian.stieger@unileoben.ac.at
+43 3842 402 2905

Due to their wide range of applications, polyurethanes are among the most important synthetic polymers with an annual production of more than 22 million tonnes (as of 2018). In addition to polyurethane foams and PUR rigid foams, advanced polyurethane elastomers, which are used as vibration insulation in the construction, railway and industrial sectors, are becoming increasingly important. Unwanted oscillations and vibrations do not only occur in technical areas, but are increasingly caused by public traffic (Fig.1). Damping materials protect machines from damage, but also reduce the impact of noise and vibration, which leads to an increased quality of life and work for residents.

PU elastomers, which consist of two components (polyol and isocyanate), are characterised in particular by high strength combined with high elongation and very good resilience. A considerable disadvantage of the production of PU elastomers is the intensive use of toxic isocyanate. For this reason, the development of new isocyanate-free elastomers is becoming increasingly important. 

In this project, the aim is to form a structure comparable to polyurethane on the basis of long-chain, modified polyols in combination with functional monomers, but also nanoparticles, and thus to generate corresponding material properties. The modified polyols carry terminal acrylate or methacrylate groups and can be light-induced polymerised. First successes were achieved by combining different acrylate macromonomers with silican nanoparticles.

At one glance

Project partners: KC, WPK, Getzner Werkstoffe (Bürs)

Contact
Mag.rer.nat. Catharina Ebner 
catharina.ebner@unileoben.ac.at
+43 3842 402 2368

The development of stretchable, conductive materials opens up the possibility of easy integration of electronic, multifunctional sensor systems, for example in clothing, or three-dimensional surfaces of machines, human skin or plastic. The motivation for the development of such sensor systems stems from the vision of realising intelligent clothing, the integration of sensor technology on textile surfaces (smart textiles, e-textiles) and the production of artificial skin (electronic skin, e-skin).

In addition to the need for simple and cost-effective production of these elastic components, the stretchability of electrical connections and contacts is an essential functional requirement. The aim of our research is to develop novel materials and processes that enable large-scale production of current-conducting, stretchable electrodes and conductor paths.

For this purpose, within the framework of the CD labs for functional polymer-based printer inks and the FFG project "CELCOS" developed new methods for the production of metallic nanoparticles without the need for toxic chemicals in an elastomeric matrix.

The metallic nanoparticles are produced by self-reduction of a stable silver complex. Based on this complex, pastes were developed that can be applied in a structured manner to sufficiently large surfaces by means of screen printing. The printed conductive tracks and electrodes show a very low change in resistance at an elongation of up to 100 % . In cooperation with Joanneum Research Weiz, AT&S and the Human Research Institute, it was possible to develop a sensor patch (strain sensors, see Fig. 1) for monitoring and detecting cardiac and respiratory activity.

At a glance
Promotion: CDG, FFG 
Project partner: Joanneum Research Weiz, AT&S, Human Research Institut

Contact
assoz.Prof. Dr. Thomas Griesser 
thomas.griesser@unileoben.ac.at
+43 3842 402 2358
 

Conveyor belts transport bulk material over several kilometres and transmit longitudinal forces of up to 8000 kN. Due to these enormous loads, elastomeric belts are reinforced with steel cables. These very long belts are assembled from shorter belt sections, which are easier to transport, and connected endlessly on site. In the area of the splices, the belt sections are joined according to a specific laying pattern of the steel cords. There are many design possibilities for this laying pattern. With strengths of only about 50 % of those of the rest of the belt, the belt joints represent the weak point of the conveyor belts, as the longitudinal forces have to be transferred here via the rubber between the ropes. 

In the 3-year bridge project of the FFG beltSim with Semperit as project partner, simple and inexpensive test specimens are to be developed that map the failure in the belt joints (reduction). For this purpose, it is necessary to know exactly the mechanical stresses in the conveyor belt but also in the possible test specimens. Finite element (FE) models are developed that automatically construct any belt joints and test specimens. At the test specimen level, physically-based damage models are developed whose parameters are determined by the tests. The developed damage models are used in the FE model for the conveyor belt and thus predict strengths of the belt. The procedure can be validated by comparing the predicted strengths with belt tests. This provides the basis for optimising belt structures, rubber compounds and ropes. 

At a glance
Promotion: Bridge-Projekt der FFG 
Project partner: Semperit

Contact
Dipl.-Ing. Dr. Martin Pletz 
martin.pletz(at)unileoben.ac.at 
+43 3842 402 2507
 

While classical polymer research usually deals with materials characterised by a passive structural function, dynamic polymer systems that can adapt to their environmental conditions have recently become the focus of basic research in Leoben. 

A new generation
In cooperation with the MUL, new elastomeric materials with switchable chemical groups are being synthesised at the PCCL. These functional elastomers react selectively to an external stimulus, such as temperature, light or pH value, and thereby change their chemical and/or physical properties. Above all, the incorporation of light-sensitive groups opens up new avenues in the production of "intelligent" elastomers, as reactions with light are subject to temporal and local control.

Self-healing with light
The light-controlled reaction of anthracene groups is used to endow elastomers with self-healing properties. Cross-linking occurs when irradiated with UV light above 300 nm while the network sites formed undergo controlled cleavage at a lower wavelength. This mechanism enables the intrinsic healing of damage in the elastomer and the repeated repair of macroscopic cracks.

Future applications

With the help of reversible switching of the cross-link density, targeted control of a wide variety of material properties such as tensile strength, elongation, adhesion or solubility is achieved. Due to this versatility, switchable elastomers can be used in a wide variety of industries such as microelectronics (Fig. 2) or the automotive sector. In addition, controlled network degradation enables the development of new recycling concepts for elastomers.

At a glance 
Promotion: FFG COMET-K1, BMDW,  bmvit, Countries STMK, NÖ & OÖ
Partner: PCCL, MUL (KC, WPK, SGK, Institute for Physics)

Contaxt
Priv.-Doz. Dr. Sandra Schlögl
sandra.schloegl(at)pccl.at 
+43 3842 402 2352
 

Starting with the first concepts in the 1960s, tape laying technologies have been used commercially since the 1980s. Among the laying technologies, the thermoplastic-processing variants are very limited and are still under development. Due to the high material costs and the high laying speeds aimed for, consolidation after the laying process is necessary to achieve a sufficient industry standard. Another complicating factor is that it is hardly possible to record and influence the material quality during the laying process and the process is only run under predefined boundary conditions. In order to better exploit the potential of the technology, in situ consolidation is to be achieved via in-line control.

"InP4 - In-Line Process Control for TP Placement Process" aims to achieve homogeneous consolidation by adapting the compaction force based on a continuously adaptive, inverse process model. For this purpose, the change of the tape geometry is recorded in-line by means of light-section sensors. The Chair for Processing of Composite Materials at the MUL, uses a modular laying system for this purpose: The system developed in-house allows the simple integration of new units such as heating or compacting systems.  

Another aspect of tape laying is the heat input. The type of heat source, the amount and the type of transfer have an influence on the component quality. Within the project, a flash lamp system (humm3TM), a relatively new heating method, is used and tested. With the system, the heating parameters can be continuously adjusted and thus serve as an element in a control loop.

The financial support provided by the bmvit as part of the RTI initiative "Production of the Future" and administratively coordinated by the FFG is gratefully acknowledged.

At a glance
Promotion: FFG, Produktion der Zukunft, 24. AS
Project partner: FACC Operation GmbH 

Contact
Neha Yadav, MA
neha.yadav@unileoben.ac.at
+43 3842 402 2721
 

Why polypropylene?

The use of additive material extrusion (filament process, FFF) is currently subject to a strong material constraint, as most commercially available filament types are made of PLA or ABS. Polypropylene (PP), on the other hand, is hardly used, but offers a number of advantages for 3D printing applications, such as higher toughness, good modifiability, low moisture absorption, and better temperature and chemical resistance. In addition, PP meets the industry's increasing demands for technically sophisticated and reliable materials. A decisive disadvantage of PP, however, is the high shrinkage caused by the high degree of crystallinity of the material. This not only affects adhesion to the print bed, but also the dimensional stability of 3D-printed components.

Warpage optimisation of 3D-printed PP compoundsAs part of the national FFG project NextGen3D (848624), up to 30% by volume of spherical fillers and fibres were added to the PP in order to minimise both material shrinkage and warpage. In order to ensure at least consistent mechanical properties and good printability of the compounds, the developed materials were optimised based on the morphology. The filament production as well as a suitable choice of parameters during the printing process played a decisive role in order to be able to generate an optimised 3D-printed component made of PP without distortion. The materials obtained were versatile and, in addition to their unproblematic processability, were particularly convincing due to the wide range of properties that could be achieved, which is a decisive advantage for users such as the BMW Group - Steyr plant.

At a glance

Promotion: FFG, Production of the future, 848624
Partner: Profactor, iRed, Hage Sondermaschinenbau, JKU Linz - Institute for Chemical Technology of Organic Substances, BMW Group - Steyr Plant

Contact
Dipl.-Ing. Stephan Schuschnigg
stephan.schuschnigg(at)unileoben.ac.at 
+43 3842 402 3511 
 

The aim of the FlexiFactory3Dp project (2017-2019) is to develop a sustainable, robust and flexible production process for complex metallic and ceramic components to be manufactured using additive material extrusion. Two case studies are being investigated: a monolithic catalytic converter for air purification and a component from the automotive sector.

The main task of the Chair of CT is to develop and improve the SDS (Shaping-Debinding-Sintering) manufacturing route. In this process, polymer components are mixed with metallic or ceramic powders and filaments are extruded from them. These are formed into components by means of material extrusion, an additive manufacturing method. This is followed by the debinding step, in which parts of the polymer are removed. The remaining powder particles are sintered together to obtain dense metallic or ceramic components. 

Highly filled systems of titanium, steel, copper, aluminium oxide and zirconium powder have already been processed into filaments at the chair. In collaboration with the project partners, different constructions of a catalytic converter for air purification were designed and produced in FlexiFactory3Dp. The project partner RHP optimised the sintering process required for this and designed a component from the automotive sector.

At a glance

Promotion: FFG, 22. AS Production of the Future 2016 China University Shanghai, 860385
Project partner: RHP-Technology GmbH, Shanghai University Research Centre of Nanoscience and Technology, Shanghai Industrial Technology Institute Intelligent Manufacturing Department

Contact
Dr. Joamin Gonzalez-Gutierrez
joamin.gonzalez-gutierrez@unileoben.ac.at
+43 3842 402 3541
 

The FFG lead project AddManu (849297) was a national research network with an international scientific advisory board and the goal of establishing additive manufacturing in the Austrian economy. The focus was on four additive manufacturing technologies that have the greatest potential for industrial application for metals as well as for ceramics and plastics. Between May 2015 and July 2018, 19 partners from research and industry from a wide range of sectors worked intensively on the further development of additive manufacturing in Austria.

The filament diameter as a decisive quality featureWithin this project, the Chair of Plastics Processing has focused exclusively on increasing the quality of additive material extrusion (filament process, FFF). In addition to successful strategies for increasing the strength of technical components and optimising the adhesion of the first deposited layer, a system for automated filament production was developed in particular. A high diameter consistency and a low ovality of the filament are basic prerequisites for a stable and reliable 3D printing process. Even small deviations in the filament diameter can significantly reduce the filling level of the print or clog the nozzle. As part of the project, a filament extrusion system with integrated diameter and speed measurement as well as a fully automated winding unit was developed. In combination with various cooling methods and a wide range of extruders, this project enables the Chair of Plastics Processing to process any thermoplastic material, no matter how complex, into filament for additive material extrusion.

At a glance
Promotion: FFG, 849297
Project partner: Airbus DS, Böhler Edelstahl GmbH, CEST Kompetenzzentrum für elektrochemische Oberflächentechnologie GmbH, FOTEC Forschungs- und Technologietransfer GmbH, GE Jenbacher GmbH, Hage Sondermaschinenbau GmbH, Joanneum Research Forschungsgesellschaft (laser production technology, functional surfaces), LAM Research AG, Lithoz GmbH, Magna Steyr Engineering AG, Mahle Austria Filtersystems GmbH, MUL (external institute chairs for forming technology, KV, SGK, KC, structural and functional materials), O. K.+Partner GmbH, PKT Präzisionskunststofftechnik Bürtlmair GmbH, PROFACTOR GmbH, RHI AG, RHP-Technology GmbH, TIGER Coatings GmbH, TU Wien (Chair of Non-Metallic Materials, Institutes of Management Sciences and Applied Synthesis Chemistry)

Contact
Dipl.-Ing. Stephan Schuschnigg
stephan.schuschnigg@unileoben.ac.at
+43 3842 402 3511 
 

Additive Fertigung (AM) in der Medizin

One strength of additive manufacturing processes is that they can produce individualised products. This characteristic makes AM particularly interesting for medical technology. Due to the currently very strong development activity, both in materials and technologies, more and more medical applications are becoming possible.

CAMed

The COMET project, funded by the FFG, brings together 18 project partners from Austria and Germany under the leadership of the Medical University of Graz. In the project, the possibilities of two materials for additive manufacturing are being researched: on the one hand, there is AM with metallic materials, which is mainly based on powder bed technologies. On the other side are plastics; the Chair of Plastics Processing is responsible for the additive material extrusion of polymer materials in the project. Among other things, metallic implants are to be replaced by plastics, which are advantageous not only because of their lower weight and defined stiffness, but also because of their permeability to X-rays.

Through the use of customised polymers and different additive manufacturing technologies for polymer materials, high-quality, personalised implants are to be manufactured directly in the hospitals, thus saving time and costs. The focus is on the well-being of patients both in the clinic - through fewer and shorter operations - and in the daily use of the implants.

At a glance

Promotion: FFG, 7. AS COMET Projects 2017, 865768

Contact
Dipl.-Ing. Stephan Schuschnigg
stephan.schuschnigg(at)unileoben.ac.at 
+43 3842 402 3511 

Dr. Joamin Gonzalez-Gutierrez
joamin.gonzalez-gutierrez(at)unileoben.ac.at 
+43 3842 402 3541
 

Additive manufacturing of plastic components by means of material extrusion

Additive manufacturing has experienced a worldwide boom in recent years. Based on this trend, 3D-printed components made of plastic are also becoming more and more interesting for various applications. Due to the low purchase costs for machines, additive manufacturing via material extrusion (Fused Filament Fabrication - FFF) in particular is becoming accessible to a wide audience. However, due to the processing method, many components produced in this way often have relatively low mechanical properties. However, in-depth studies of the processing conditions have shown that a clever selection of the process parameters can significantly increase the mechanical properties. This makes it possible to use components manufactured using the FFF process in structurally stressed parts.

Optimisation of mechanical properties

In current investigations, both classical mechanical characteristic values, such as stiffness and strength, as well as fracture-mechanical toughness parameters are determined depending on the process parameters. As can be seen from the illustrations, immense differences in properties can be achieved depending on the settings selected. Some materials can even be optimised in terms of process control to such an extent that they exhibit almost homogeneous properties in all spatial directions. This offers immense advantages, especially for components subject to high mechanical loads and their design.

At a glance

Promotion: This work was supported by the FFG as part of the AddManu project ("Strengthening Austrian value chains for generative manufacturing in industrial production", grant agreement 849297).

Contact
Dr. Florian Arbeiter
florian.arbeiter(at)unileoben.ac.at 
+43 3842 402 2122

The development of biocompatible materials for 3D printing opens up the possibility of digital fabrication of complex, geometric structures in medical technology. Of the common 3D printing processes for plastics, stereolithography is particularly convincing due to its very high resolution. This technology, which is based on the photopolymerisation of liquid resins, is particularly suitable for the production of biomedical products, where high fitting accuracy and high surface quality are required. Commercially used resin systems are largely based on acrylate and methacrylate monomers, which are only suitable to a limited extent for the manufacture of medical products that come into contact with tissue or mucous membranes due to their great brittleness and comparatively high cytotoxicity.

As part of the research activities of the CD Laboratory for functional polymer-based printing inks, biocompatible resin systems are being developed for the additive manufacturing of medical applications and devices adapted to the patient (e.g. orthodontic dental splints, see Figure 1). These resin systems are based on the radical reaction of multifunctional alkyne and thiol monomers (see Figure 2) and exhibit significantly higher biocompatibility than stand-der technology resins. The special polymerisation mechanism of this curing reaction leads to the formation of very homogeneous polymeric network structures, resulting in unique thermo-mechanical properties (ductility and toughness). 
The research work of the CD Laboratory on the development of biocompatible resins for the additive manufacturing of orthodontic splints was recently awarded the Science Prize of the German Society for Orthodontic Aligners. 

At a glance

Promotion: Christian Doppler Research Society
Project partner:  Schmid Rhyner AG,  Lithoz GmbH, Wollsdorf Leder Schmidt & Co Ges.m.b.H.

Contact
assoz.Prof. Dr. Thomas Griesser 
thomas.griesser(at)unileoben.ac.at 
+43 3842 402 2358
 

Photoinitiators are used to trigger radical or cationic polymerisations under UV light. In a new research approach, the extent to which photoinitiators can be coupled to the surface of inorganic particles to obtain migration-free photoinitiators for UV curing was investigated. 

Within the framework of the FFG lead project AddManu and in a strategic project of the PCCL, five types of photoinitiators (acylphosphine oxides and other Norrish type 1 initiators) with coupling-capable trialkoxy silyl groups were prepared. These photoinitiators were coupled to the surface of silica particles via condensation. 

The curing of acrylate resins based on tetrahydrofuran acrylate was investigated with the functionalised particles and with the free photoinitiator (as a comparative component) by photo-DSC and real-time FTIR. Indeed, the photo-polymerisation of the acrylate using the coupled photoinitiators occurs with similar reaction rate and comparable double bond conversion as with free initiators. For thiol-ene resins, the coupled photoinitiators show a lower reaction rate, but ultimately a comparable double bond conversion. 

The extractable fraction of photoinitiator (or its cleavage products) was investigated by Soxhlet extraction followed by GC/MS analysis. With a high degree of functionalisation of the silica particles, the extractable content of photoinitiator (or its cleavage products) is below the detection limit. For industrial applications, e.g. printing inks for food packaging, coupled photoinitiators can thus ensure a quantitative conversion of the monomers and a low extractability of the photoinitiator. 

At a glance 

Funding: FFG lead project addmanu
Project partner: ETH Zurich (Prof. H. Grützmacher), PCCL (Dr. S. Schlögl)

Contact
Univ.-Prof. Dr. Wolfgang Kern
wolfgang.kern(at)unileoben.ac.at 
+43 3842 402 2351
 

The future of flying

In civil aviation, the demand for transport is expected to double within the next 15 years. Not least due to growing environmental awareness, increased social acceptance and increasing scarcity of resources, the demand for environmentally friendly, resource-saving and low-noise aircraft will increase significantly for all leading global aircraft manufacturers. 

Fibre-reinforced polymer composites play a crucial role when it comes to manufacturing modern aircraft. Compared to metals, the ratio of mass to stiffness can be exceeded by up to four times. This holds enormous potential for saving fuel or increasing range and payload.

Developments in manufacturing

Within the framework of Evolution#4, strategies are being developed for the fourth industrial revolution in aircraft manufacturing, which is currently still largely characterised by manual activities. Automated production options based on the resin transfer moulding process with integrated quality control as well as concepts of the digital twin are developed and demonstrated using the production of a wing component.

Support through Take Off

The Evolution#4 project is funded by the Federal Ministry for Transport, Innovation and Technology (bmvit) as part of the Austrian research programme "Take Off" and administered by the Austrian Research Promotion Agency FFG. The project consortium includes the industrial partners Alpex Technologies GmbH, aerospace & advanced composites GmbH, Fill GmbH and Brimatech Services GmbH as well as the University of Leoben as a research partner.

At a glance

Funding: bmvit RTI initiative "Take Off", administered by the FFG
Project partner: Alpex Technologies GmbH, aerospace & advanced composites GmbH, Fill GmbH, Brimatech Services GmbH, MUL

Contact
assoz.Prof. Dr. Ewald Fauster 
ewald.fauster(at)unileoben.ac.at 
+43 3842 402 2708
 

Initial situation

For many technical applications, a fine balance must be found between stiffness and toughness. Materials with high stiffness often have the disadvantage that they exhibit very brittle fracture behaviour. Many biological materials, on the other hand, are both stiff and tough at the same time, which is due to their filigree microstructure. The skeleton of the deep-sea sponge Euplectella aspergillum, for example, consists of more than 99 % SiO2 (bioglass) and is interspersed with wafer-thin, concentric protein layers. These layers act as crack stoppers and give the glass skeleton remarkable toughness.

Imitation of nature

As part of an FFG Bridge project, research is now to be carried out to find out whether such concepts can also be adapted for polymer materials. Highly mineral-reinforced and toughness-modified polypropylene will be used instead of bioglass and protein. Using methods of elastic-plastic fracture mechanics, it can be shown that the soft intermediate layers represent a significant obstacle to the growth of cracks.

Application

The knowledge gained should, in conjunction with FE simulations, enable the design of an optimised multilayer composite. As a result, particularly resistant materials with targeted layer architecture are expected. As a result, new areas of application for plastics can be opened up or existing challenges can be met more efficiently and in a way that conserves resources.

At a glance

Funding: FFG - Bridge 
Project partner:  ESI, MCL

Contact
Dr. Florian Arbeiter
florian.arbeiter(at)unileoben.ac.at 
+43 3842 402 2122
 

Advancing digitalisation has already massively expanded the possibilities for controlling and monitoring industrial processes, and will continue to bring significant changes to the way products are made in the future. Key technologies of the digital factory include the Internet of Things, IPv6 and OPC/UA, cloud solutions, Big Data, artificial technology and intelligent sensor-actuator combinations. These systems are increasingly being used by industry in high-wage countries to simultaneously increase the efficiency and flexibility of production processes and thus stay one step ahead of competitors from low-wage countries. 

In the SORIM project, a control system for rubber injection moulding machines is to be developed which, taking into account the material and process status, can react independently to critical deviations and ensure consistent moulded part quality.

This task represents a particular challenge in rubber injection moulding because (1) the rubber compound is a living chemical system and its properties are significantly influenced by the mixing process and storage, and (2) even slightly deviating process conditions in the injection moulding process can cause major changes in the quality of the moulded part, i.e. the goal of zero-defect production can only be achieved by analysing all available data and a precise knowledge of the influencing factors.

In the SORIM project, the knowledge gained from previous projects about the influencing factors that determine quality in rubber injection moulding is expanded to include the component of online process monitoring. This will make it possible to create a machine control system that regulates the quality of the moulded parts independently and without operator intervention.

At a glance

Funding: FFG COMET Competence Centre Programme (PCCL)
Project partners: PCCL, MUL-SGK, SKF Group, Engel Austria GmbH, Simcon kunststofftechnische Software GmbH and Dr. Gierth Ingenieurgesellschaft mbH, Woco 

Contact
Dipl. Ing. Thomas Hutterer
thomas.hutterer(at)pccl.at 
+43 3842 429 6229

assoz.Prof. Dr. Gerald Berger-Weber
gerald.berger-weber(at)unileoben.ac.at 
+43 3842 402 2904
 

Hollow-body composite components based on fibre-reinforced plastics can be produced very efficiently using bladder-assisted resin transfer moulding (BARTM). However, the high flow resistance of the textile reinforcement structure limits the technically feasible and economical production, especially for long components. This becomes even more critical when the process is implemented with a fast-curing or a highly viscous resin. In order to meet these process-inherent challenges, cascade infiltration in BARTM was investigated as part of the bmvit-funded NoVoTube project (FFG No. 853453). The approach pursues a significant reduction of the effective flow path length and, concomitantly, the filling time. This could be achieved by sequential filling via several resin feed points along the longitudinal axis of the component.

During implementation, ring gates proved to be clearly advantageous compared to point gates. In addition, the risk of air pockets in the component could be reduced by venting points at the cascaded ring gates. For the realisation of a fully automated cascade infiltration process, an efficient process control was implemented. This enables accurate switching of the individual infiltration cascades according to the filling state reached. A suitable fill front detection system was integrated for this purpose. NIR sensor technology has proven to be a reliable technique for detecting the flow front. Furthermore, the NIR sensor technology offers the possibility to additionally detect the mixing ratio resin/hardener and the curing state of the reaction resin. This makes inline quality monitoring possible.

At a glance
Funding: bmvit programme "Production of the Future" administered by FFG
Project partners: Thöni Industriebetriebe GmbH, superTEX composites GmbH, Research Center for Non Destructive Testing GmbH

Contact
Univ.-Prof. Dr. Ralf Schledjewski
ralf.schledjewski(at)unileoben.ac.at 
+43 3842 402 2701
 

The InQCIM project addresses the flexible production of plastic components without loss of quality and pursues a new, interdisciplinary solution approach with an "intelligent injection moulding tool".

The intelligent injection moulding tool (iSGW) is to be fully integrated into the production cell as a cyber-physical system that can independently monitor component quality and react in situ and automatically to external disturbances and (internal) process fluctuations. 

For this purpose, the iSGW needs: 

• New, robust structure-borne sound sensors for comprehensive condition monitoring in the injection mould.
• An optical full inspection of the component quality directly in the production cell.
• New and comprehensive OPC/UA information models for injection moulding machines, injection moulds and peripherals. Implementation as a bidirectional OPC/UA interface injection moulding machine - quality controller - injection mould.
• A new machine learning based FDC (Fault Detection and Classification) system.
• An integrated, adaptive and intelligent quality controller with the ability to automatically and specifically react to quality deviations during production.
• A modern, networked injection moulding production cell.
• In the long term, intelligent injection moulds will enable Austrian and European injection moulders to further increase the quality of their products and to maintain their competitiveness against competitors from the Far East with consistently high quality.

At a glance

Project partners: SGK (management), TU Vienna (Institute of Production Engineering and High-Performance Laser Technology), PCCL, Wittmann Battenfeld GmbH, Miraplast Kunststoffverarbeitungs GmbH, MAHLE Filtersysteme Austria GmbH, Julius Blum GmbH, automotive supplier (anonymous)

Contact
assoz.Prof. Dr. Gerald Berger-Weber
gerald.berger-weber(at)unileoben.ac.at 
+43 3842 402 2904

Priv.-Doz. Dr. Dieter P. Gruber
dieter.gruber(at)pccl.at 
+43 3842 429 6228
 

The term "hybrid material combination" has been challenging various research disciplines for several years. Nevertheless, the possibilities that can be achieved through such material combinations in terms of material properties seem limitless. Especially in processing, however, hitherto unknown questions arise: How can an interface of the two materials be produced in a sufficient quality? How can an economical production be guaranteed? The HybridRTM project was designed to answer precisely these questions.

The goal was defined as the development of a one-step manufacturing process that enables the production of a hybrid composite made of carbon fibre reinforced plastic (CFRP) and steel. The result is the One-Shot-Hybrid Resin Transfer Moulding (OSH-RTM) process. In this process, the epoxy resin required to produce the CFRP material is used simultaneously as a matrix material and also as an adhesive for the steel component. This integration of the bonding process into the component manufacture reduces the work steps required in the conventional manufacturing process (component manufacture and subsequent bonding) and thus enables an increase in efficiency.
 
As an example, the illustration shows the production of a roof bow with steel connection points for welding to the rest of the vehicle body. By using a foam core, the weight of the component can be kept low despite high stiffness values. With the help of model-based process monitoring and control, it was also possible to ensure a consistently high quality of the components.

At a glance

Funding: bmvit programme "Production of the Future" administered by the FFG
Project partner: Alpex ­Technology GmbH, Austrian Institute of ­Technology GmbH, SGL Composites GmbH, bto-Epoxy GmbH

Contact

assoz.Prof. Dr. Ewald Fauster 
ewald.fauster@unileoben.ac.at
+43 3842 402 2708

The CDL for High Efficiency Composite Processing aims to develop fundamental understanding of the manufacturing processes for high quality composite aerospace components. One of these processes is (fibre) winding, a very energy and cost efficient automated process. Winding is already an established process in composite processing. Nevertheless, even more possibilities can be opened up with the large-scale use of robotics and state-of-the-art digital manufacturing methods. 

At CDL, the relatively new, innovative process of dry winding of fibre bundles (rovings) and unidirectional tapes is being researched. This process has great potential to become a fully automated part of a process chain whose goal is to replace the expensive and time-consuming production in an autoclave ("out of autoclave"). The main questions are: Can pre-formed semi-finished products (preforms), which are subsequently liquid impregnated, be produced by winding dry fibres? Can existing winding equipment be further developed so that it is suitable for high-speed winding of different materials? 

To investigate the fundamental aspects of the process, a multifunctional robotic cell is currently being developed. The flexible design of the robot head enables not only the winding of rovings but also the discontinuous depositing of pre-impregnated semi-finished products. The process properties as well as the influence of the manufacturing process on the material properties and process parameters are being investigated. The aim is to obtain information on different steps of the process chain and to better understand the process limits. The main challenges are:  Winding complex structures without slipping the fibre,, avoiding fibre damage due to excessive yarn tension, impregnating the wound preform and controlling different interdependent process parameters. Ultimately, the aim is to develop a sound knowledge base for this technique that extends from virtual production to complete mastery of the real process.

The author would like to thank the BMDW as well as FACC Operations GmbH as a partner of the CDL for funding the research carried out. He would also like to thank the CDG for its support.

At a glance

Funding: BMDW 
Supervision: CDG
Project partner: FACC Operations GmbH

Contact
Univ.-Prof. Dr. Ralf Schledjewski
ralf.schledjewski(at)unileoben.ac.at 
+43 3842 402 2701
 

Due to their high specific strength and low specific weight, continuous fibre-reinforced polymers are increasingly gaining ground as substitutes for metals. However, the available material data for this class of materials is mostly limited to quasi-static characteristic values, such as the elastic modulus or the strength.
For the design of dynamically-cyclically loaded components, knowledge of the local Wöhler curves (S/N curves) of the materials is a prerequisite, which are significantly influenced by component-specific aspects such as fibre orientation, load type, medium stress, temperature, etc.. For the prediction of the service life of cyclically loaded components, a method was developed that takes into account the above parameters but also typical failure mechanisms in this class of materials, such as fibre breakage, inter-fibre breakage or delamination, in the calculations. When analysing the structural stresses via finite element methods, the local orthotropic material behaviour of the individual laminate layers is included.

Although the characterisation of the fatigue behaviour of continuous fibre-reinforced polymers is complex and a large number of tests are necessary to record the essential influencing parameters, it has been possible to set up a hypothesis for the prediction of the fatigue strength of orthotropic composites taking into account a puck criterion modified for cyclic loads and to implement it in existing software (FEMFAT®). The methodology is also applicable for load spectra and multi-axial loads. First results on components underline the potential of the methodology, but also show limitations that need to be addressed in the future.

At a glance

Project partner: Magna Powertrain, Engineering Center Steyr

Contact
Univ.-Prof. Dr. Gerald Pinter
gerald.pinter(at)unileoben.ac.at 
+43 3842 402 2101
 

This project aims at the development, characterisation and technological implementation of a new class of composite materials (functional, hierarchical composites for structural applications). These new materials have adjustable structural parameters at all size levels (micro- and nanoscale). This makes it easy to develop materials that have improved mechanical properties. In addition, nanoscale structure makes it possible to monitor components during their operation. Epoxy-based fibre composites are used as a reference point for the materials developed in the project. 

The properties of the matrix are changed with the help of nanoscale fillers as follows:

• By functionalising the particle surfaces with reactive organic groups, controllable interactions between particles and polymer matrix are achieved. These can be adjusted by radiation, so that on the one hand fillers with weak (to increase toughness) and on the other hand with strong matrix interaction (increase strength and modulus) can be produced.
• An electrically conductive network consisting of conductive fillers is created in the composite. This provides the opportunity to make damage accumulations in the material visible during operation.

The integration of the developed material into industrial production is initially being carried out at prototype level, e.g.: Wind turbines (Compozite Ltd.) and applications in the automotive sector (SGL Composites GmbH). Likewise, opportunities are being created to develop special epoxy resins for further applications (bto-Epoxy GmbH).

At a glance

Funding: Transnational call for proposals "M-era-net" with Austrian and Romanian participation. Austrian part: Production of the Future (FFG)
Project partners: bto-epoxy GmbH, University POLITEHNICA of Bucharest, SC COMPOZITE SRL, SGL Composite GmbH 

Contact
Dipl.-Ing. Dr. Michael Feuchter
michael.feuchter(at)unileoben.ac.at 
+43 3842 402 2110
 

Composite structures play a key role in the constant effort to optimise mechanical structures in all areas of engineering with regard to load-oriented design and low weight at the same time. 

In order to fully exploit the potential of innovative materials, it is necessary, contrary to current design practice, to consider the optimisation of structure and material in a coupled manner.  This requires both the determination of the optimal spatial distribution and the optimal utilisation of the material, i.e. orientation and anisotropy of the material tensor, controlled by the microstructure (see figure).

So far, this is not possible with the current methods of structure optimisation based on numerical optimisation (topology and shape optimisation, dimensioning). Existing approaches to material optimisation concentrate on directly finding physically meaningful solutions by providing a limited number of predefined candidate angles for optimising the material orientation (Discrete Material Optimisation), with the problem of local optima. Other approaches that circumvent this limitation (Free Material Optimisation) face the problem that the optimisation results in a theoretically optimal, but not always physically realisable structure.

The aim is therefore to develop a method that, based on a reasonable number of design variables, provides a physically realistic material configuration without unnecessarily restricting the design space. This leads to more efficient, lighter structures that have applications not only in the aerospace industry, but in many areas of engineering.

Contact
Univ.-Prof. Dr. Clara Schuecker
clara.schuecker(at)unileoben.ac.at 
+43 3842 402 2501 

The legal requirements of the EU on the circular economy pose great challenges for the Austrian textile industry, especially since textiles often consist of two or more materials, which makes material recycling very difficult. In the course of the Tex2Mat project, a separation process based on an enzymatic process is to be developed for cotton-PET blended fabrics. The pure PET obtained in the process (from towels, hotel and hospital linen) is to be reprocessed in such a way that it can be used again for the spinning process and ultimately for the original purpose. 

For this purpose, the reprocessed PET fibres were systematically analysed in the first step to determine the extent to which the material properties have changed through processing and use compared to virgin material. Based on these findings, the material is brought back to a level from which it can be spun by means of appropriate additivation or recondensation.

Suitable for injection moulding

Furthermore, PA mixtures that were originally used in industrial textiles are to be tested for their suitability as a material for technical injection moulding components. The requirements for the material properties for spinning differ considerably from those for injection moulding. 

After corresponding material analyses, injection moulding tests were carried out to determine optimal setting parameters. These tests showed that the fibre material can be injection moulded well with only small changes to the process parameters. Mechanical tests have shown that although the modulus of elasticity and strength meet the requirements for technical components, the notched impact strength is below expectations. Extensive trials are underway to improve this.

At a glance

Funding: FFG/BMWFW - COIN Programme
Project partners: ecoplus.Niederösterreichs Wirtschaftsagentur, Kunststoff-Cluster, TU Wien, BOKU Wien,
DI Monika Daucher Engineering, Ing. Gerhard Fildan GmbH, Herka GmbH,
Huyck.Wangner Austria GmbH, Multiplast Kunststoffverarbeitung GmbH, Starlinger & Co Gesellschaft m.b.H., Salesianer Miettex GmbH, Thermoplastkreislauf GmbH

Contact
Dipl. Ing. Uta Jenull-Halver 
uta.jenull-halver(at)unileoben.ac.at 
+43 3842 402 3542
 

Development and processing of bio-based fibre-matrix composites

Bio-based composites have experienced growing interest in recent years and are establishing themselves in more and more market segments such as the automotive, transport, furniture and consumer goods industries. The combination of renewable plant-based reinforcing fibre and bio-based polymers allows the production of ecologically efficient composite components. The property profile of the fibre-matrix composite materials can be specifically adjusted over a wide range, which makes the material interesting for a variety of applications.

Within the framework of the FFG project RSBC, resin synthesis on the basis of vegetable oils is being investigated. The research focus on the MUL side is the systematic analysis of suitable resin-hardener mixtures for the production of high-performance, bio-based duromers. In the liquid impregnation process, the natural fibre reinforcement and the polymeric matrix material are subsequently processed into the composite component. The analysis of the material properties during processing by using different sensor technologies and the development of a suitable method for process monitoring make a decisive contribution to ensuring reproducible component quality and reliable processing of the bio-based composites. 

The practical implementation is being tested with the production of a cladding component for agricultural and construction machinery. The comparison of the process and component properties with the glass-fibre reinforced composite material used as standard for this application shows the potential of the bio-based materials used. The research work is accompanied by an evaluation from ecological and economic points of view as part of an eco-efficiency analysis.

At a glance

Funding: bmvit - RTI Programme: "Production of the Future" of the FFG
Project partners: Jaksche Kunststofftechnik GmbH, Kompetenzzentrum Holz GmbH, bto-epoxy GmbH, R&D Consulting GmbH, Kästle GmbH

Contact
Moritz Salzmann, MSc
moritz.salzmann(at)unileoben.ac.at 
+43 3842 402 2717

Foamed plastics can now be found in many areas of everyday life, from packaging to sports and leisure articles. By foaming plastics, a material with very special characteristics can be produced: in addition to weight and cost reduction, properties such as high electrical resistance, low thermal conductivity and high sound absorption can be achieved, for example. These properties are mainly influenced by the foam structure. For example, an improved insulating effect is achieved by increasing the number of foam cells. However, this high number leads to a reduction in the polymer content, which is responsible for the mechanical stability. By cross-linking polymer chains, both the stability can be improved and the field of application of plastics can be shifted to higher temperatures.

Extruded polymer foams are produced by introducing gas into the polymer melt. The gas can be added in different ways, for example by using physical blowing agents (e.g. carbon dioxide). In this type of foaming, the gas is injected directly into the cylinder of the extruder. However, a nucleating agent is additionally needed here for the formation of the gas cells.

The idea of the MULTIFOAMREX project is to chemically modify a nucleating agent that is typical in the plastics industry. Through this modification, the filler should support both the formation of the cells and the cross-linking between the individual polymer chains during the foaming process. The aim is to improve the foam structure of polyolefin foams and at the same time develop a more stable foam product.

At a glance

Funding: FFG
Project partner: KC, KV, Steinbacher Dämmstoff GmbH

Contact
Ass.Prof. Dr.rer.nat. Gisbert Rieß
gisbert.riess(at)unileoben.ac.at 
+43 3842 402 - 2311

It is impossible to imagine life today without components made of plastics. In order to survive in global competition, component developers and manufacturers - many of which are SMEs - must constantly present innovative solutions made of plastic and hybrid components. To do this, they must master (while reducing costs) weight reduction and miniaturisation, increasing functionality and the use of material combinations and new manufacturing processes.

They are thus faced with the challenge of constantly keeping track of the many innovations on the market and in research and quickly integrating them into their own products, which can hardly be solved without customised training. This is where the qualification network InKuBa came in. 

The one-year training InKuBa was designed and implemented together with all project partners and the KVKL Leoben (see also p. 69). In 15 days of training, 41 experts from industry and research taught the 27 participants about materials, surfaces and sustainability, about systematic product development and integrative simulation, and about (new) production methods for large series and additive manufacturing. The participants had to pass on what they had learned in their own companies, apply it to practical, business-relevant issues under the supervision of experts from the participating universities and finally present their findings to all partners. 

The proof of competence was provided by a final examination (written examination, presentation and examination discussion). Afterwards, the participants received a personal certificate according to ISO 17024 from the accredited certification body SystemCert. With this procedure, it was possible to sustainably build up innovation competence in the companies.

At a glance

Funding: FFG Research Competences for the Economy
Project partners: Chairs of the Dept. KT., AMB, External Institute, Vienna University of Technology (Institute of Materials Science and Technology), University of Linz (Institute of Polymer Injection Moulding and Process Automation), ANTEMO Anlagen & Teilefertigung GmbH, Oberhumer Klaus und Partner Gesellschaft m.b.H., KSZ GmbH, Schöfer GmbH, Miraplast Kunststoffverarbeitungsgesellschaft m.b.H., Jabil Circuit Austria GmbH, Seletec Plastic Products GmbH & Co.KG, KEBA AG, IB STEINER, PADESIGN/product & automotive design e.U., SWARCO FUTURIT Verkehrssignalsysteme Ges.m.b.H., Joh. Fuchs & Sohn Gesellschaft m.b.H., Wild GmbH, FT-TEC GmbH, Philips Austria GmbH

Contact
assoz.Prof. Dr. Gerald Berger-Weber
gerald.berger-weber(at)unileoben.ac.at 
+43 3842 402 2904
 

Professional recycling processes and cycles enable the long-term optimal use of a material and the sustainable use of raw material sources. In addition to the direct reuse of products, mechanical recycling (i.e. the recovery of polymer material from plastic residues including production waste), which is characterised by the extensive preservation of the polymer structure as well as the entire energetic material value, represents a particularly sustainable recycling option for polymer materials. 

Technical biopolymers have not yet been separately collected and thus recycled in terms of waste technology, as they only account for 1% of the total plastics market. However, the predicted growth in production volumes requires the establishment of appropriate ecologically and economically sensible recycling routes for technical biopolymers as soon as possible, as well as their integration into waste material flows, for which comprehensive knowledge of their general recyclability is necessary. In a comprehensive study, the principle mechanical recyclability of representative biopolymers based on renewable raw materials was therefore analysed. Special focus was placed on the identification of processing-related degradation mechanisms and times and their effects on the material characteristics. Although there is a partial need to stabilise the materials, especially against hydrolytic degradation, the results demonstrate a high potential of the investigated biopolymers for mechanical recycling. Further work addresses the optimisation of recyclate quality and the integration of technical biopolymers into existing recycling processes.

At a glance

Funding: bmvit/Comet programme, PCCL project V-2.S2
Project partner: PCCL

Contact
Assoz.Prof. Dr.mont. Katharina Resch-Fauster
katharina.resch-fauster(at)unileoben.ac.at 
+43 3842 402 - 2105

During the injection moulding of short glass fibre reinforced thermoplastics, increased abrasive wear occurs in the melt-bearing components of the machine and the mould, which leads to process fluctuations, component defects and high maintenance costs.

In the COMET project XTribology (duration 2015-2018) at the Tribology Competence Centre AC2T research, wear test methods were further developed to simulate the so-called "hedgehog effect" occurring in the melting area and material combinations were investigated to minimise adhesive wear. At MUL, the influence of dissipative heating on abrasive wear was also investigated experimentally and by means of simulation. 

The most remarkable result in the application-related platelet wear test was a massive drop in hardness of a high-alloy powder metallurgical steel at the wear surface from originally 770 HV0.5 to 450 HV0.5 after spraying 50 kg PA66 filled with 50 wt.% short glass fibres (total 210 spraying cycles). The cause was assumed to be a massive near-surface temperature increase in the steel caused by dissipation due to the high injection volume flows and pressures as well as micro-chipping. The cyclically introduced heat flow changed the near-surface microstructure and thus massively accelerated the wear. Simulations using SigmaSoft® showed a melt temperature rise to 700 °C, 0.9 µm from the wall. This resulted in an increase of the temperature at the steel surface to 465 °C after only one injection process. 

In the future, the influence of dissipation on the wear of plastic mould steels will have to be investigated in more detail for both low-alloy and high-alloy steels and the wear-resistant steels will have to be further developed in the direction of longer service lives.

At a glance

Funding: Comet
Project partners: Wittmann Battenfeld GmbH, AC2T research GmbH, TU Vienna - Institute of Materials Science and Technology

Contact
Dipl.-Ing. David Zidar
david.zidar(at)unileoben.ac.at 
+43 3842 402 2910