Study of Beaming Large High-Modulus Fiber Tows

Abstract

A warp beam used to supply warp to the loom instead of a creel, will provide convenience in weaving fabrics manufactured from large tows of high modulus fibers as it will require less floor space and reduced frequency of changing the supply packages. Winding and unwinding large tows is a problem since individual filaments tend to break under variable stress-strain conditions. It is therefore necessary to optimize the manufacturing processes. A review of the previous work done in this area showed that only limited amount of work has been published. Available published research has been studied and documented.

Theories describing the cross-sectional behavior of conventional yarns have been studied and correlated to the large tows. Normal beaming and weaving conditions were simulated to understand the problems faced. Experiments were conducted to simulate the beaming of large tows and their results were analyzed to study the behavior during this process by applying a variety of twist and tension level combinations on the tows. Packing factor was used to analyze the experimental data since it normalizes any variations in the tow dimensions. Abnormality in the value of packing factor, which influences the behavior of tows during winding and unwinding, was found for a particular load value, independent of the twist level.

This work clearly proved that the application of tension during beaming causes a change in the cross-sectional area of large tow, resulting in the disintegration of the binder holding the individual filaments together. The disintegration of the binder allows the cross-section of the tow to vary on application of tension since there will be no external force holding the filaments together. A further increase in tension at this point may bring the filaments close together in a compact configuration and may result in the tow applying more pressure on the tows of previous layers wound. As a result, filament or tow breaks may occur during further processing. Future recommendations for a different approach to the problem and to understand the abnormality have been discussed.