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The aim of this paper was to investigate the effect of carbon fibre (CF) length and preparation prior to carding on the mechanical properties of hybrid yarns as well as composites consisting of CF and polyamide 6 (PA 6). The hybrid yarns are manufactured using an optimised process route of carding and drawing with a flyer machine from virgin staple CF (40/60/80/100 mm) and PA 6. In order to explore the effect of fibre preparation on the mechanical properties of hybrid yarns as well as composites, virgin staple CF and PA 6 fibres were prepared by varying the mixing type prior to the carding process. For this purpose, the fibres were mixed either by a fibre-opening device or supplied directly to the carding machine without prior mixing. The CF content of the card webs produced is kept at 50 volume %. Hybrid yarns were produced with a twist of 102 twist/m and then thermoplastic unidirectional (UD) composites were manufactured from them. The investigations revealed the influence of the input CF length and mixing type on the mechanical properties of hybrid yarns and thermoplastic UD composites. [ABSTRACT FROM AUTHOR]

The quality of web produced by a carding machine is largely influenced by the shape and height of the gaps between card clothings of workers and the doffer cooperating with the main cylinder as well as between the doffer clothing and doffing blade. The following paper describes the methodology of selection of a structural form and basic dimensions of the carding machine shafts and cylinders taking into account the gap shape in the zones of card clothing cooperation. For the study to be complete, optimisation of the blade and comb shaft cross-sections was also performed. The benefit from optimisation of the carding machine components is the improvement in the quality of the web - the final product of carding. [ABSTRACT FROM AUTHOR]

In this paper, flow patterns, such as the velocity distribution along the radius of the nozzle block at section A-A and static pressure distributions along the nozzle block axis and its radius at section A-A, affected by the nozzle block's structure parameters and the velocity at the jet orifice exit in Murata vortex spinning are investigated by the method of numerical computation. The results show that the tangential, axial and radial velocities inside the nozzle block are significantly affected by the jet orifice angle and velocity at the exit of the jet orifice as well as by the diameter at the inlet of the nozzle block. Static pressure distributions inside the nozzle block are significantly affected by the jet orifice angle, the velocity at the exit of the jet orifice, the outer diameter of the hollow spindle and the distance from the inlet of the nozzle block to the inlet of the hollow spindle. [ABSTRACT FROM AUTHOR]

The goal of this research work was an exhaustive analysis of the influence of carding units (double and triple ones) on the quality of wool yarn. Certain factors that greatly influence the inequality of woolen yarn were analysed. A description of measurement methods used for the determination of the inequality of linear density are presented in this article. The technological parameters of double and triple carded units, as well as their influence on the production of woollen yarns is discussed. For measurement of differences in the inequalities of yarns of the same linear density but produced form different carding units an Uster testing set was used. The influence of three carding units of different technological parameters on the formation of periodic irregularity in the yarn linear density was exhaustively analysed. [ABSTRACT FROM AUTHOR]

This paper is one of a series of studies on the carded-web forming process with the application of static electricity to carded nonwoven fabric process. Electrostatic carding technology was used to apply static electricity to the worker-roller of the carding machine, in which the electrostatic application could change the fibre transformation, to improve the fibre loading of carding and then increase the carding performance and fibre web uniformity. Furthermore, the fibre load of the carding element, the surface potential on the roller and the uniformity and nep count of the fibre web would be measured to investigate the effect of the applied static electricity on the carding performance of different types of fibres at various process parameters. The results showed that there was a relationship between the applied static electricity and the fibre loading of carding roller. It signified that the electrostatic method affected the uniformity of nonwoven fabric. In addition, it was found that the change of fibre loading on the worker-roller depended on the polarities in those tribo-electrification process, as well as those that the static electricity was applied to. [ABSTRACT FROM AUTHOR]