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Title: The measurement of weft velocity and its application in the optimisation of weft insertion in air-jet weaving
Author: Junaid, Fadi
Awarding Body: University of Leeds
Current Institution: University of Leeds
Date of Award: 2013
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This research project was aimed at studying the air-jet weft insertion process by computer simulation for optimising air usage. Initial studies showed the need of a suitable instrument for measuring the dynamic weft velocity profile on the weaving machine, for validating the accuracy of computer simulation. Trials carried out using the weaving machine stroboscope proved its inadequacy for the purpose. With the unavailability of a better device, it was decided to develop an instrument fit for the purpose. A novel opto-electronic weft velocity measuring instrument was developed, having the necessary performance for up to 50 or more weft insertions without stopping the weaving machine, and provide data files for obtaining weft velocity profiles of individual weft insertions. The initial single weft sensor based design was developed into a dual sensor based design which enabled data analysis based on cross-correlation. Due to the ease with weft insertion velocity profiles of successive weft insertions could be obtained, it was realised that the 'average weft insertion profile' can be calculated, which gave what could be considered the 'true' dynamic weft velocity curve. The new measuring instrument and the determination of the dynamic weft insertion velocity profile are totally new outcomes. Further research led to the realisation that the twin sensor based design enabled weft velocity measurement without having to mark the weft, and hence the ability to use this technique during actual weaving operations, since the fabric is not spoilt by weft markings. This outcome was not considered possible previously. The above developments enabled carrying out a computer simulation of the insertion process, results of which compare favourably with the measured weft velocity profile. This also enabled optimising weft insertion parameters when changing the weft yarn as well as giving the potential for continuous optimisation.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available