ENGINEERING THERMOPLASTICS | INNOVATION
nation with the thermoplastic composite sheets are to be used to create a demonstrator for a rear seat backrest, which was designed by project partner Brose Fahrzeugteile. The TPRC (Thermoplastic
Composites Research Center) in Enschede, The Nether- lands, reports that it has developed structural analysis capabilities for over- moulded structures that take into account the strength of the interface between the injection moulded and continuous fibre reinforced material domains. The virtual environment consists of several software packages, as well as a Degree of Melting (DoM) model which was developed in the Composites OverMolding Production TEchnology (COMPeTE II) project. The stamp forming step is simulated with AniForm from which the fibre directions are exported to the structural simulation Abaqus. The injection moulding step of the over-moulding process is simulated in Autodesk Moldflow. The interface temperature history is exported to the DoM model and the short fibre orientations and initial strain-state are exported to Abaqus via the Autodesk Advanced Material Exchange. The DoM model predicts the amount of crystal-
lites that is being dissolved in the insert during the over-moulding process for semi-crystalline materials. This determines the maximum attainable interface strength as the crystallites severely impair the bonding process between the two material domains. The DoM prediction is then correlated with mechanical testing data, using a newly developed test geometry, to create a quantitative
Left: Demonstrator geometry with woven insert developed during COMPeTE II
Below: Structural analysis of the demonstrator geometry
interface strength prediction. A demonstrator geometry part developed in the
COMPeTE II project allows for mechanical testing and is used to validate the structural analysis capabilities. The simulation results show good correlation with the observed deformation mode and strength during mechanical testing of the demonstrator geometry, says TPRC.
Materials Ineos Styrolution introduced a new generation of thermoplastic over-mouldable composites called StyLight at K 2016. The company says the material, based on a modified SAN (styrene acrylonitrile) matrix reinforced with glass or carbon fibres, produces parts with very good surface aesthetics.
Tape inserts in injection moulding
Tape inserts offer enormous potential for injection moulding parts. That’s the conclusion of a major consortial project led by the Aachen Center for Integrative Lightweight Production, AZL, and the Institute for Plastics Processing at RWTH Aachen University, IKV. For suitable components, product costs and component properties can be positively influenced, they say. “We are so satisfied with the
progress and results of the study that we have already defined several follow-up projects and are also forming a consortium for the short- term identification and implementa-
www.injectionworld.com
tion of new applications,” says Prof. Christian Hopmann, founding profes- sor of the AZL and head of the IKV. In cooperation with 20 industrial
partners, the AZL and IKV carried out a detailed analysis of tape inserts in injection moulded components over a period of eight months. The tapes, which are a few tenths of a millimetre thick, are continuous fibres, typically made of glass or carbon, completely impregnated and embedded in a thermoplastic matrix. The tapes can be precisely aligned to the loads in a component and are used primarily in high-performance applications with
the aim of weight reduction. The aim of the conducted analysis was the identification of potential applications and the estimation of a wider range of applications. “We know that the integration of small amounts of high-performance tapes into typical injection moulded parts can contribute significantly to material savings in their manufacture. Light- weight construction is only a second- ary effect, one of the main drivers for establishing the technology is cost reduction,” says Dr. Kai Fischer, who heads the fibre-reinforced production technology unit at the AZL.
January/February 2020 | INJECTION WORLD 29
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