Experimentelle Validierung eines neu entwickelten Verarbeitungsverfahrens für Elastomere

Translated title of the contribution: Experimental validation of a novel processing method for rubbers

Manuel Treitler

    Research output: ThesisMaster's Thesis

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    Abstract

    Rubbers exhibit a property profile that optimally meets the requirements of the sealing industry. However, production of seals is associated with above-average costs, especially in the case of large dimensions and complex geometries. As part of the FFG Bridge project "RubExject" (project number: 855873), a new processing method for rubber parts was developed which is based on Exjection®-Technology and compensates for the disadvantages of current manufacturing methods. The Exjection®-Technology is a combination of extrusion and injection molding, in which the cavity is integrated into a movable sliding carriage. The major benefit is the possibility of forming complex geometries with high dimensional accuracy, and at the same time, low injection pressure and clamping force. Within the scope of this master thesis, the system limits and the possible process window of the RubExject process for a carbon black filled, sulfur-curing Nitrile Butadiene Rubber (NBR) were first determined for the subsequent experimental validation of the RubExject process. This showed that good parts can only be produced with a closed cavity and injection times shorter than the scorch time. Using a statistical design of experiments (DoE), the effects of the vulcanization time and the injection volume flow on sealing-relevant target parameters such as compression set, tensile stress at break and elongation at break of the manufactured parts were investigated. Longer process times lead to lower compression set, i.e. to higher degrees of cross-linking, independent of the composition of the process time (injection time and vulcanization time). The comparison of RubExject parts with compression molded reference plates showed that similar part properties can be achieved with the RubExject process. Moreover, significantly lower injection pressures and cavity pressures were measured compared to the classic injection molding of rubbers. Although the RubExject process can be used successfully to produce parts, it is not yet suitable for manufacturing large seals. However, there is the potential to transfer the process to other part geometries.
    Translated title of the contributionExperimental validation of a novel processing method for rubbers
    Original languageGerman
    QualificationDipl.-Ing.
    Awarding Institution
    • Montanuniversität
    Supervisors/Advisors
    • Berger-Weber, Gerald, Supervisor (internal)
    • Stieger, Sebastian, Co-Supervisor (internal)
    Publication statusPublished - 2020

    Bibliographical note

    embargoed until 02-03-2022

    Keywords

    • Rubbers
    • injection molding
    • extrusion
    • Exjection
    • Nitrile Butadiene Rubber
    • seals
    • Design of Experiments

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