How do you control yarn imperfections?
Higher fiber openness results in less imperfection in yarn due to the fact that higher fiber openness results in better fiber individualization in card sliver, which in turn produces quality yarn. The carding process has a major impact on yarn imperfection.
What are the faults of yarn?
From all the above yarn faults, some important yarn faults have discussed in the following:
- Slubs: Slubs are fish-shaped thick places from 1-4cm long and about 5-8 times longer than the average yarn diameter at the thickest portion.
- Cracker: …
- Spinners Doubles: …
- Bad Piecing and Double Gaiting: …
- Slough Off: …
How faults are generated in yarn?
POSSIBLE REASONS OF FAULT
Bad condition of carding, blow room, trash in yarn. Fluffs foreign matters, dirty drafting zones, neps. Ring front zone dirty, fly waste in trumpet. Fibres damaged in process, spindles without aprons.
How do you reduce thin spots in yarn?
are a few points to be looked into in ring frames for the control of long thin places. Optimum back-zone settings with a reduced break drafts helps to produce yarns with less number of thick/thin places and slubs.
How do you increase yarn strength?
Factors that affect yarn strength are as follows –
- Staple length. Longer staple cotton gives higher strength and this is true even in the case of synthetic staple fibre such as nylon and terylene. …
- Fibre fineness. …
- Fibre strength. …
- Twist. …
- Evenness. …
- Fibre length variation and distribution. …
- Fibre finish. …
- General factors.
What is yarn imperfection?
Imperfections can be defined as the total number of neps, thick and thin places in a given length of yarn. … A yarn with more imperfections will exhibit poor appearance grade, lower strength and poor performance in weaving is likely to produce fabric with low quality.
What is yarn irregularity?
The irregularity or unevenness of a yarn is commonly deﬁned as the variation in ﬁneness along its length and more appropriately as the variation in mass per unit length along the yam’. It is expressed as U% or CV%.
What is CV in yarn?
2. C.V% A statistical measure of the variation of the individual readings (Coefficient of observed variation). In general the lower the C.V.% the better is the measured value of the yarn.
How is yarn IPI calculated?
The imperfection index (IPI) is the sum of yarn thin places/ km (-50%), thick places/km (+50%) and neps/km (+200%) per kilometer of tested yarn for ring spun yarn [2, 59] .
What do you mean Classimat?
The classification of yarn defects according to their size and length into 23 standard classes is used extensively to certify yarn quality, to help control spinning processes and to optimize yarn clearing at the winding stage. …
What process is used after simplex?
The drawn sliver is used as a feeding material in a simplex machine. After completion of this process, the resulting material is called roving. We can say that “a simplex is a machine which converts the drawn sliver into a thin strand of fibres having some amount of twist”.
What is Classimat?
The next-generation USTER® CLASSIMAT 5 features innovative and powerful technology for defect classification and prevention. It enables both yarn producers and users to achieve significant improvements in quality consistency across an extended range of parameters.
What is Neps yarn?
Textile terms and definitions define a `Nep’ as a small knot of entangled fibers that usually comprises dead or immature fibers. Neps in cotton continue to be a major problem in the cotton yarn manufacturing process. The two main factors affecting nep formation are fiber characteristics and mechanical processing.
What is the main difference of thick place and Neps?
Thin places indicate the mass reductions, thick places indicate the mass increase and neps indicates the increase of short mass. Average of ten tests was taken for final result at each trial.