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Fiber migration to yarn | how to migrate fiber to yarn | parameters of fiber migration to yarn



According to the Textile Institute the fiber migration may defined as the change in distance of a fiber or filament from the axis of a yarn during yarn production process.

PARAMETERS FOR FIBER MIGRATION:
A)    Staple Length of Fiber: With the increase of staple length migration will also increase.
B)    Tension: With the increase of tension of fiber migration will also increase.
C)    Mode of Spinning:- Fiber migration in yarn depends on the methods of manufacturing processes.

FIBER MIGRATION IN YARN:
If a particular fiber were to process into a variety of staple and continuous filament structures, textured and un textured, one could expect substantially different characteristics in each yarn. To fully understand or predict the performance of yarns, it is necessary to explore the structure of yarn in details.
The study of fiber geometry (spatial configuration of fibers) in yarn was initiated in the early 1950’s by Morton and Yen, who developed a fiber tracing technique to indicate the position of individual fibers relative to the fiber axis. A small portion (less than 1 % by weight) of dyed fiber is thoroughly blended with similar but un dyed fiber before conversion into yarn. The yarn is immersed into a liquid media of the same refractive index as that of the fibers, causing the un dyed fibers to become practically transparent and allowing the dyed (tracer) fiber to be observed and scanned microscopically.
The successive segments of the fiber or filament being scanned are usually shown to be positioned in various annular zones in the yarn structure from core to surface to core in migration patterns of various periodicities. The term fiber migration is used to describe the relative fiber movement during processing and the position of fiber in final yarn structure. Fiber migration, which is expressed by various parameters and indices, depends on many fiber  properties , characteristics of the fiber assemblages, and processing

IDEAL MIGRATION OF FIBER IN YARN:

The ideal migration pattern is defined as one in which the fiber migrates regularly & uniformly from outside to the center of the yarn and the back to outside in such a way that the density of packing of fibers in the yarn is constant throughout the yarn.


This was developed by Morton & Yen, who developed a fiber tracing technique to indicate the position of individual fibers relative to the yarn axis. A small proportion (less than 1% by weight) of dyed fiber is thoroughly blended with similar but un dyed fiber before conversion into yarn. The yarn is immersed into a liquid media of the same refractive index as that of the fibers, causing the un dyed fibers to become practically transparent and allowing the dyed (tracer) fiber to be observed and scanned microscopically and thus the migration is measured. Here the colored fiber is called tracer fiber.


B. Measurement of Fiber Migration by Riding’s Experiment:
Riding used a different technique to estimate the measurement of migration. He did it by measuring the relative radial positions.


From the above ratio r/R he measured the amount of fiber migration of colored filament in yarn.
He used the liquid in which the yarn is immersed and which had the same refractive index as that of viscose and nylon (i.e. continuous filament yarn). He used a mirror to carryout the experiment for analytical analysis. He has used one black filament in the yarn to study the migration behavior. He carried out experiments at an interval of half a turn of twist & 200 such measurements were taken to get the result.


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