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The air-jet texturing process for synthetic continuous multi-filament yarns is more versatile than any other texturing process and provides the most effective simulation of natural staple spun yarns. The process itself is inadequately understood, and the ultimate goal of the work is to achieve a better understanding of the mechanism of the texturing process and to make suggestions for more efficient nozzle designs in order to increase productivity and thereby reduce production costs.

Two completely different approaches have been used to study the mechanism of the air-jet method of bulking filament yarns. Part A is an aerodynamic study of the nature of the air flow and of its characteristics, and of the yarn's behaviour during the bulking process. The experimentation involves the use of scaled-up models of the du Pant type 9 commercial Taslan air-jet and of a typically used parent yarn. The study is extended to include a modification of the jet suggested by earlier workers. The results of these investigations provide new evidence regarding the mechanism of the process and the construction of bulked yarns of this type. It is also concluded that the commercially used air-jet on which the model study has been based, is not ideally designed from the stand-point of efficiency, stability and ease of operation. In Part B, a suggested mechanism of the air-jet bulking action is simulated by a purely mechanical means. The simulation of the process has been so effective that yarns of the air-jet bulked type are produced by a method not requiring any compressed air. The preliminary work leading to the design of an experimental apparatus is briefly reported. Theoretical and experimental investigations of the process are made, and the bulked yarn properties for various parent yarn particulars and processing conditions are measured and assessed. An economic evaluation of the process has been attempted, based on a comparison with the limited cost figures available for Taslan processing. - The individual nature of each of the two main investigations has necessitated that the results should be separately discussed in the ultimate Chapter of each Part of the thesis. Suggestions for further work are also made for each of the two techniques.

An investigation has been carried out into the twist blockage which may occur when yarns pass over guides or other surfaces. The influence of primary physical parameters such as surface curvature, are and length of contact, yarn twist level and tension and yarn/surface friction have been investigated together with secondary parameters such as yarn surface, pressure, angle of approach etc. As a result of these investigations, three mechanisms of blockage have been identified. The first of these occurs especially with doubled yarn in which the components lie side by side on the guide surface and blocked twist builds up until sufficient torque is developed to turn the yarn over against the couple generated by the components of yarn tension and reaction on the guide surface. In the second mechanism blocking torque is generated by components of friction on the yarn surface at right angles to the yarn axis. These orthogonal friction components may arise from interaction between the topography of the twisted yarn surface and the guide surface or may be generated by forces arising from an angular orientation of yarn to guide. The third mechanism is intermediate between the other two where a singles yarn (or its equivalent) is flattened on the surface and resistance to twist transmission is generated partly by internal friction within the yarn and partly by yarn/guide frictional forces. The main circumstances under which these different mechanisms may operate, have been identified and suggestions made for minimising the blockage of twist.

Productivity in every sector is essential, Production areas like textile require more production, more profit with less cost. Everyone should play their own role in achieving better production rate in these working sectors.There are many factors which can improve the productivity, but here we will focus on some specific areas. By working on these issues or factors, we can achieve our productivity goal. There are challenges for production managers and they need to take healthy measures for the enhancement in their production rates e.g. to find the best raw material available, to train its team and keep them updated to the latest technologies etc.This thesis is comprised of different factors which can affect the productivity in textile field. Here we will discuss the textile sector of Pakistan. All the information and collection of data is taken out and is referenced to the textile industry of Pakistan. / Program: Magisterutbildning i Applied Textile Management