Potential für die Heizzeitverkürzung beim Kautschukspritzgießen unter Nutzung von Scher- und Dehnerwärmung

Translated title of the contribution: Potential for cure time reduction in rubber injection moulding utilising shear and elongational heating

Georg Chaloupka

    Research output: ThesisMaster's Thesis


    The cure time has the biggest portion in the overall cycle time in the production of thick-walled moulded rubber parts. Especially rubber injection moulding provides a great potential for process optimisation. The FFG-Bridge-project “Heizzeitverkürzung”, in which´s context this thesis takes place, pursues an approach of targeted use of shear and elongation heating by using conical nozzles. The present study examines in practical experiments the influence of different nozzle-geometries on the mass temperature and the curing behaviour in rubber injection moulding. Compared to former approaches within the project “Heizzeitverkürzung”, the injection work has been kept constant by limiting the hydraulic pressure. It is of special interest if nozzles with variant types of angles and capillary length would lead to divergent cure times at the same state of cure. The measurements of the compression set, as an indicator for the degree of cross-linking, showed that neither the feed angle nor the capillary length has an impact on the minimal cure time. The pressure loss was identified as the main factor, which itself depends on the attainable injection pressure and the diameter of the nozzle. A series of tensile tests could not reveal molecular damage, caused by excessive shear stress, or pre-cured spots. Finally a parameter study was carried out by means of a calculation programme to determine the heating time reduction as a function of part thickness. Different thermal conductivities as well as varying tool and mass temperatures were taken into consideration. This data clarify that an increased injection temperature results in reaching the defined significance threshold of 5 % cure time reduction for parts of only 5 mm thickness. Up to 38 % of cure time reduction can be achieved under optimum process control. These statements are valid only for the tested SBR-material and require extensive and sophisticated material characterisation. Process optimisation for cure time reduction requires a profound set-up of material, tool and machine.
    Translated title of the contributionPotential for cure time reduction in rubber injection moulding utilising shear and elongational heating
    Original languageGerman
    Awarding Institution
    • Montanuniversität
    • Friesenbichler, Walter, Supervisor (internal)
    Award date15 Dec 2017
    Publication statusPublished - 2017

    Bibliographical note

    embargoed until 08-11-2019


    • rubber
    • injection moulding
    • cure time reduction
    • injection work

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