Spun yarns frequently have “objectionable faults” inclusive of very thick or very thin places. The thick places, known as slubs, may be the end result of a collection of badly drafted fibers twisted collectively to shape a pretty quick period withinside the yarn, numerous instances the yarn diameter. Poor piecing of yarn breaks in the course of spinning, the twisting in of unfastened airborne fibers, and the faulty operation of equipment also can bring about slubs and skinny places. Ineffective starting and cleansing and/or infection of uncooked material can reason ugly overseas remember withinside the yarn. Chapter 6 describes ordinary yarn faults that may stand up in the course of processing and which have degrading outcomes on fabric quality. In ring-spun yarn manufacturing, such faults are eliminated on the winding stage of the manufacturing sequence. In unconventional spinning systems, inclusive of rotor and air-jet spinning, the clearing of faults takes place on computerized machines.
Generally, Yarn fault clearer are classified on working principle.
- Mechanical yarn clearer
- Electronic yarn clearer
Electronic yarn clearer are more
precise and efficient. so that’s why now a day electronic yarn mostly replaced
mechanical yarn clearer.
Mechanical Yarn Clearer are working with two different principle;
- Fixed blade
- Swinging blade type
Fixed
Blade Type
In this type of mechanical yarn clearer yarn pass out between two fixed metallic blades. The gap between the two blades depends on the yarn diameter, type of yarn, percentage of clearing required. When a yarn tries to pass out with greater thickness. In this case, yarn is jammed between two blades and breaks. Optimum setting generally set between a range of 1.5-2.0 times higher than yarn diameter.
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| Credit:- Fundamentals of yarn winding by Milind Koranne |
Swinging
blade type
The principle
of operation of the oscillating blade type mechanical yarn cleaner or the trap
type, which is composed of a spring-loaded inclined blade that remains in an inclined position due to a spring. There is enough
space between the knife and the deck for the normal thread to pass through. The thick place of thread
presses the blade, forcing it to move in the direction of the thread running. This will close the gap between the blade and the platform
to do not allow the thread to pass through and break the thread. The gap between
blade and platform is depending on the thread and type of blade. Normally gap
is 3 and 5.5 times bigger than the thread diameter.
Electronic Yarn Clearer
Electronic yarn clearer recognizes yarn faults on the basis
of electronic principles and is able to eliminate a wide range of yarn faults
very efficiently.
Instrumental measurement of yarn Yarn
The result of the electronic measurement of the yarn defects can also be used to quantify and classify the defects present in the yarn.
Dimensions Fault
- Thickness
- Length
- Thickness
The thickness
or diameter of the fault can be expressed as a number that indicates how often the thickness of the fault is compared to
the mean thickness. Therefore, the number “2” indicates that the thickness of the fault is twice the average. The
change in cross-sectional area is displayed in. Therefore 0% means that there is no change in the mean cross-sectional area. A change in the
cross-sectional area of 100% means a thick point with a cross-sectional enlargement of 100%. Area, e.g.,
Double Diameter from normal.
The thinnest point in relation to the diameter can be indicated as follows: If an error is displayed regarding a multiple of the mean diameter (or thickness) of the thread, the
number '1' indicates the normal diameter, so a thinner one Place can be indicated by a fraction. times 0.63 means that the thread is thinnest 0.63 times than the normal diameter of the thread.
Length
Whether a given diameter/mass deviation is objectionable depends on the length over which it continues. A slight increase in wire diameter / cross-sectional area that continues over a long length is objectionable. individually objectionable, but its frequent frequency in non-periodic/periodic intervals can be objectionable.
Yarn fault classification
Graphical Representation
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| Credit:- Fundamentals of yarn winding by Milind Koranne |
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| Credit:- Fundamentals of yarn winding by Milind Koranne |
Ref:- Fundamentals of yarn winding by Milind Koranne
Fundamentals of Spun Yarn Technology by Carl A. Lawrence
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