x % Span length is the distance spanned by x %of fibers in the specimen being tested when the fibers are parallelized and randomly distributed and where the initial starting point of the scanning in the test is considered 100%. This length is measured using "Digital Fibrograph‘.
Yarn Engineering
Fibrograph Method
The original idea of the photoelectric scanning or Fibrograph method has been developed by Hertel in 1940 for testing cotton lint. This test method is much faster than the array method and is used widely in fiber laboratories for measuring fiber length and length distribution.
Effective Length of Cotton Fiber
The effective length is the upper quartile of the fiber length distribution obtained by ignoring short fibers whose length is below half the effective length.
Length parameters of cotton fibers
The most frequent length in a fibrous sample is called staple length. Staple length is one of the most important factors of cotton quality because both fiber fineness and fiber tensile strength are associated with staple length. The longer staples are usually finer and stronger than the shorter staples.
Fiber length measurement
The fiber sorter is an instrument which enables the sample to be fractionalized into length groups. The Baer sorter, the Shirley comb sorter, and the Suter-Webb sorter are the most popular method of the fiber sorter. Basically, the operation involves four main steps:
Preparation of a fringe or tuft with all fibers aligned at one end.
The separation or withdrawal of fibers in order of decreasing length.
The preparation of a sorter diagram by laying the fibers on a black velvet pad in decreasing order of length, the fibers parallel and their lower ends aligned along a horizontal base line as shown in Figure.
The analysis of the sorter diagram.
Fiber Length and Length Distribution
After fineness, length is the most important property of a fiber. The length of cotton is directly related to its spinning performance. Knowledge of fiber length is necessary to manufacture a yarn of specific size on ring spinning system and typically longer fibers are used to manufacture fine yarns. Longer fibers are generally more uniform, finer, and stronger than shorter ones.
Graphical Representation of Mass Variations
0shares Facebook Twitter LinkedIn Tumblr Digg Print Reddit Weibo Xing Blogger MySpace Graphical Representation of Mass Variations Graphical representations are aimed at providing easy analysis possibilities as well as providing more complete information than the numerical estimates. The following graphical representations are common with the latest generation evenness testers. Spectrogram 3D Spectrogram Variance Length Curve […]
Yarn Evenness II It’s Classification
0shares Facebook Twitter LinkedIn Tumblr Digg Print Reddit Weibo Xing Blogger MySpace Yarn Evenness & It’s Classification Evenness, Unevenness, regularity, and irregularity are common terms used to describe the degree of uniformity of a textile product. In the textile field, the uniformity of products like the lap, sliver, roving or yam is expressed in terms […]
Study on four truck circular knitting machine.
Most single-jersey fabric is produced on circular machines whose latch needle cylinder and sinker ring revolve through the stationary knitting cam systems that, together with their yarn feeders, are situated at regular intervals around the circumference of the cylinder. The yarns is supplied from cones, placed either on an integral overhead bobbin stand or on a free-standing creel, through tensioners, stop motionsand guide eyes down to the yarn feeder guides.
Methods of Evenness Testing
The optical method measures the variations in diameter of a yarn and not in its mass. The instrument an infra-red transmitter and two identical receivers. The yarn passes at speed through one of the beams, blocking a portion of the light to the measuring receiver. The intensity of this beam is compared with that measured by the reference receiver and from the difference in intensities a measure of yarn diameter is obtained.