Twist Test Methods and Influencing Factors
Twist test is an important part of yarn inspection. It is related to the strength, elongation, appearance, style, etc. of yarns and fabrics. Different yarns have different structural characteristics, and their twist testing methods are also different.
Basic concept
To understand twist testing, you must first understand what twisting is. Twisting is a necessary condition for yarn formation. Short fibers can be made into yarns with certain physical and mechanical properties through twisting; filaments often need to be twisted in order to increase the tightness between single filaments, facilitate processing, and improve fabric properties.
Number of twists
Twisting is to cause two cross-sections of parallel straight fiber slivers to rotate relative to each other. The number of relative rotations of the two cross-sections is called the number of twists.
Twist
Twist refers to the number of twists per unit length of yarn.
Twist coefficient
In actual production, the twist coefficient is often used to express the degree of twist of the yarn. The twist coefficient is a physical quantity that is directly related to the twist angle of the fibers on the surface of the yarn. When the volume weight of the yarn is constant, the twist coefficient can represent the degree of twisting of yarns of different thicknesses.
Twist direction
According to the direction in which the fibers on the surface of the yarn are tilted, the twist directions of the yarn include Z twist and S twist. For example, a double-stranded yarn is ZS twisted, which is composed of two Z-twist single yarns plied in the S twist direction.
Z twist: After twisting, the tilt direction is from bottom to top and from left to right, which is called Z twist.
S twist: After twisting, the tilt direction is from bottom to top and from right to left, which is called S twist.
Twist shrinkage
Yarn twist shrinkage refers to the length of yarn shortened or extended by twisting, expressed by twist shrinkage.
Twisting is to cause two cross-sections of parallel straight fiber slivers to rotate relative to each other. The number of relative rotations of the two cross-sections is called the number of twists.
Twist
Twist refers to the number of twists per unit length of yarn.
Twist coefficient
In actual production, the twist coefficient is often used to express the degree of twist of the yarn. The twist coefficient is a physical quantity that is directly related to the twist angle of the fibers on the surface of the yarn. When the volume weight of the yarn is constant, the twist coefficient can represent the degree of twisting of yarns of different thicknesses.
Twist direction
According to the direction in which the fibers on the surface of the yarn are tilted, the twist directions of the yarn include Z twist and S twist. For example, a double-stranded yarn is ZS twisted, which is composed of two Z-twist single yarns plied in the S twist direction.
Z twist: After twisting, the tilt direction is from bottom to top and from left to right, which is called Z twist.
S twist: After twisting, the tilt direction is from bottom to top and from right to left, which is called S twist.
Twist shrinkage
Yarn twist shrinkage refers to the length of yarn shortened or extended by twisting, expressed by twist shrinkage.
Yarn twist tester
To determine yarn twist in double or plied yarns for traditional or twist/re-twist technique manually, a twist tester is utilized. For S and Z twist yarns, the test length is adjustable up to 30 cm (12 inches).
Click here to get more details about the yarn twist tester.
Right yarn grip rotation can be done in either the clockwise or the counterclockwise way. It is capable of adding pre-tension and has a magnifier to verify the level of yarn parallelization.
On the dial, there are 10 broad scales, each of which incorporates 10 small scales. Each wide scale corresponds to one round of the clip rotating.
Calculate the twist of 1m yarn according to the following equation,
T=1000/L×n
Where, n— the number of the untwist
L—the length of the yarn (mm)
Click here to get more details about the yarn twist tester.
Right yarn grip rotation can be done in either the clockwise or the counterclockwise way. It is capable of adding pre-tension and has a magnifier to verify the level of yarn parallelization.
On the dial, there are 10 broad scales, each of which incorporates 10 small scales. Each wide scale corresponds to one round of the clip rotating.
Calculate the twist of 1m yarn according to the following equation,
T=1000/L×n
Where, n— the number of the untwist
L—the length of the yarn (mm)
.jpg)
Comments
Post a Comment