In elastomer technology, mold-filling part production is generally associated with high energy costs and waste due to partly empirically obtained process parameters resulting in defective goods, whether directly seen after production or as short-runners returning from the application field.
Hence, efforts to understand rheological effects and their characterization for rubber compounds as basis for the layout of more reliable production process are of high interest from a commercial view.
All-in-all, these problems lead to an increasing amount of energy consumption and rubber waste, aggravating the environmental problems. In addition, the generation of rubber waste contributes to the loss of natural resources and by a consequence to an increased carbon footprint. These features are now pushing stakeholders active in rubber manufacturing to reinvent their fabrication to align these production processes with the priorities of the resource-consumptive- economy/industries and the policy of the European Commission.
In this context, the 2 years OptiMold project aims at rethinking the process design of rubber material production by implementing highly efficient and close-to-practice compound characterization concepts allowing most reliable mold filling simulations to identify highly efficient mold layout criteria and process parameters.
State of the Art
Recently, advanced rheological characterization methods have been developed based on improved high-pressure capillary with the evaluation of the pressure dependency of viscosity. This method has been proven useful in generating rheological data appropriate for mold filling simulation with consideration of the pressure drop along the fill channel path and the associated changes in viscosity, whereby the well-known dependency on shear rate and temperature are also taken into account. Nonetheless, further investigations seem necessary, especially considering the compressibility of the in-flow material and, possibly strongly correlated to this, wall slippage behavior.
Methods
This will be achieved by investigating and developing strong-coupled rheological modeling, rheological testing, mold filling simulation, and injection molding tests with advanced machinery equipped with multi-sensoring for local pressure and temperature. The main point is, to achieve already the rheological data by considering in-parallel occurring rheological effects generally not taken into account in standard material characterization and in most mold-filling simulations. Verification of the methods for industrial production processes and the correlation with final part performance is essential. To ensure the consistency of developed concepts, this will be validated for rheological measurement, for laboratory test molds and industrial production molds, each by processing and simulation.
Principal objectives and deliverables:
- Identification of improved rheological equipment and modelling for rubber compounds
- Adaption of models into mold filling simulation to optimize the prediction reliability
- Verification of rheological and simulative concepts by injection trials with multi-sensor equipped test molds
- Correlation of simulation with injection processing for industrial part molding and with part performance
- Recommendations for reliable mold evaluation procedure aimed for reduction of defective good
Scientific Partners | Contact |
Deutsches Institut für Kautschuktechnologie e.V. Eupener Str. 33, 30519 Hannover Germany | Dr. Jens MEIER Dr. Benjamin Klie |
Bursa Uludağ University, Engineering Faculty, Automotve Eng. Department TR16059, Nilüfer/Bursa/Türkiye | Prof. Dr. Murat YAZICI myazici@uludag.edu.tr |