Yarn Twist Essay Example
iram gul
Twist
1/4
1) Introduction:
Twist is the measure of the spiral turns given to yarn in order to hold the fibres or threads together. Twist is necessary to give a yarn coherence and strength. Twist is primarily instructed in to a staple yarn in order to hold the constituent fibres together, thus giving strength to the yarn. False twist is used in textured yarns. The effects of the twist are twofold: As the twist increases, the lateral force holding the fibres together is increased so that more of the fibres are contributed to the overall strength of the yarn. As the twist increases, the angle that the fibres make with the yarn axis increases, so preventing them from developing their maximum strength which occurs when they are oriented in the direction of the applied force. As a result, at certain point the yarn strength reaches a maximum value after which the strength is reduced as the twist is increased still further (Fig 1). The twist value required for the maximum strength of yarn is higher than the normal use since increased twist also has an effect on other important yarn properties. A small amount of twist is used in continuous filament yarn to keep the filaments together, but as twist is increased the yarn strength decreases below its maximum value. But because of the variability of the individual filament strengths, the initial effect of twist is to support the weaker filaments in the yarn (Fig 2). A filament yarn will be stronger than the equivalent staple fibre yarn as a comparatively large amount of twist is always needed in a staple yarn. Sometimes intermingling is used instead of twist.
2) Types of twists: 3) Twist effects on yarn and fabric properties:
a) Handle: • As the twist level in a yarn is increased it becomes more compact because the fibres are held more tightly together, so giving a harder feel to the yarn. • Because of decrease in the yarn diameter, its covering power is reduced. • A fabric made from a high-twist yarn
Twist
1/4
1) Introduction:
Twist is the measure of the spiral turns given to yarn in order to hold the fibres or threads together. Twist is necessary to give a yarn coherence and strength. Twist is primarily instructed in to a staple yarn in order to hold the constituent fibres together, thus giving strength to the yarn. False twist is used in textured yarns. The effects of the twist are twofold: As the twist increases, the lateral force holding the fibres together is increased so that more of the fibres are contributed to the overall strength of the yarn. As the twist increases, the angle that the fibres make with the yarn axis increases, so preventing them from developing their maximum strength which occurs when they are oriented in the direction of the applied force. As a result, at certain point the yarn strength reaches a maximum value after which the strength is reduced as the twist is increased still further (Fig 1). The twist value required for the maximum strength of yarn is higher than the normal use since increased twist also has an effect on other important yarn properties. A small amount of twist is used in continuous filament yarn to keep the filaments together, but as twist is increased the yarn strength decreases below its maximum value. But because of the variability of the individual filament strengths, the initial effect of twist is to support the weaker filaments in the yarn (Fig 2). A filament yarn will be stronger than the equivalent staple fibre yarn as a comparatively large amount of twist is always needed in a staple yarn. Sometimes intermingling is used instead of twist.
2) Types of twists: 3) Twist effects on yarn and fabric properties:
a) Handle: • As the twist level in a yarn is increased it becomes more compact because the fibres are held more tightly together, so giving a harder feel to the yarn. • Because of decrease in the yarn diameter, its covering power is reduced. • A fabric made from a high-twist yarn