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Oral Poster

Ceramic Fibre Processing with the 3D braiding machine

Tuesday (21.02.2017)
18:09 - 18:12
Part of:


Structural materials for applications over 1000 °C in a corrosive atmosphere are key elements for the development of traffic engineering and metallurgy. Oxidic fibre composites are appropriate for these applications because of their damage tolerance behavior towards high temperatures and gradients. In the research project “fibre reinforced oxide composites” a porous matrix is reinforced with a load capable optimised three-dimensional ceramic fibre structure. In order to process brittle ceramic fibres with the braiding process, tribological adaptions of the 3D braiding machine are crucial. Thus new bobbins have to be developed. The scientific background for the development of new bobbins is systematical tribological testing. The braiding process is analysed by the use of the 5-Step-Tool for systematic tribological investigations. In the first step all contacts between braiding yarn and braiding machine are identified. As result, eight relevant influence factors have been identified. Six tribological systems are modeled on a tribological test bench called Tribometer. Firstly the number of contacts between yarn and machine elements and the resulting wrap angle are evaluated. Secondly different bobbin elements and recently existing bobbins are compared regarding their filament breakage rate. Process parameters are tested to identify the operation point for ceramic fibre processing. As 3D braiding requires dynamic yarn storage for flexible bobbin movements, the cylinder diameter of the bobbins is investigated to minimise fibre breakage during constant on and off winding of fibres. Ceramic fibres have to endure friction stresses to itself. Thus fibre/fibre friction is examined. With all these trials fundamental information for choosing a braiding bobbin concept is given. For further reduction of ceramic fibre breakage during processing, different coatings are tested. This tribological study is used for three dimensional braiding of highly brittle ceramic fibres. Based on this study specialized bobbins are produced and three dimensional braided prototypes are manufactured.

 

Speaker:
Dipl.-Ing. Lisa Papenbreer
RWTH Aachen University
Additional Authors:
  • Prof. Dr. Thomas Gries
    RWTH Aachen University