2 edition of new technique for the measurement of single yarn twist found in the catalog.
new technique for the measurement of single yarn twist
Raymond Geoffrey Taylor
Ph.D thesis, November 1975, Postgraduate School of Studies in Textile Technology, University of Bradford.
|The Physical Object|
|Number of Pages||193|
Digital image analysis techniques in the spatial and frequency domains for twist measurement of yarns are described. A spatial technique is developed to extract the twist angle through the analysis of the yarn core image. Then, a Fourier transformation technique is applied to yarn images to measure the orientation of the fibre on the yarn surface. Finally, a hybrid method that incorporates Cited by: Determination of the amount and direction of twist by yarn twist tester Introduction: Twist is defined as the measure of spiral turns genre to a yarn in order to help the constituent fibres or threads to yelhen according to indicate a standard method for determination of yarn twist.
Yarn Twist. In all yarn spinning systems, twist is used to hold the fibers together. The frictional forces created by the twist determine the yarn’s strength and elongation characteristics. “Twist multiple” is the measure of twist per unit length, and twist direction is described as “S” or “Z.”. Twisting, in yarn and rope production, process that binds fibres or yarns together in a continuous strand, accomplished in spinning or playing operations. The direction of the twist may be to the right, described as Z twist, or to the left, described as S twist.. Single yarn is formed by twisting fibres or filaments in one direction. Ply yarn is made by twisting two or more single yarns.
Variation per yarn. Twist is needed in yarn to hold the fibres together, and is added in the spinning and plying processes. The amount of twist varies depending on the fibre, thickness of yarn, preparation of fibre, manner of spinning, and the desired result. Fine wool and silk generally use more twist than coarse wool, short staples more than long, thin more than thick, and short drawn more. Chenille yarn (which will be denoted as CY in the subsequent parts of the paper) is produced as a result of placing a yarn (pile yarn) spun from various fibers in the periodic twist gaps aligned along the axes of the two distinct yarns (core yarns) which are spun around one another while following a helical model with elliptical cross-section is given in Fig. 1, in which the approach Cited by: 4.
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The paper presents a new method for determining yarn twist that eliminates the drawbacks of the presently used 'reverse-twisting method'. The new method may be described as a.
This technique is also known as the ‘direct count method‘, as the twist in the yarn is directly counted. Construction: The below ﬁgure depicts the salient features of a single yarn twist tester incorporating the straightened ﬁber technique.
The instrument consists of two pillars, A and B, mounted on a rigid base C. That’s (for me) the only difference so no new technique, therefore I would only give 1 star to this book. The technique of the stitches used in this book, is clearly explained, there are some beautiful patterns in it; only 9 projects from which half can please me.
The snood on the flap is the most beautiful pattern therefore 3 stars/5(62). Amount Of Twist-For many practical purpose this method of expressing the amount of twist serves quite well,but the expression contains no reference to the count of the yarn.A coarse yarn with 20 T.P.I has vastly different twist characteristics to a fine yarn with 20 using an expression known as the "twist factor" or "Twist Multiplier" it is possible to appreciate the twist character.
Effect of single-yarn twist and ply to single-yarn twist ratio on hairiness Table 3 and 4 shows the hairiness of tex × 2 and tex × 2 yarns respectively. The results show that the hairiness value decreases as the single-yarn twist increases. This is due to the increase in the. This is the relation between yarn twist and yarn count where constant K is termed the “twist factor” or twist multiplier” and is directly proportional to the tangent of the twist angle.
Math: Calculate the twist angle of a spun cotton yarn twisted to give a twist factor of 7. Twist multiplier: A course yarns with 20 TPI has vastly different twist characteristics to a fine yarn with 20 TPI.
following terms used in this standard: direction of twist, single yarn, spun yarn, twist, twist factor, twist multiplier, and yarn. Refer to Terminology D and Terminology D for deﬁnitions of other terms used in this standard. Summary of Test Method A speciﬁed length of specimen is mounted in a twist device.
A New Technique for the Measurement of Single Yarn Twist. Author: Taylor, R. ISNI: Awarding Body: University of Bradford Current Institution: University of Bradford Date of Award: Availability of Full Text: Access from EThOS. Twist has important effects on the physical properties of yarn.
Low-twist yarn is lofty and is usually preferred for knitting because of its softness, covering power, and warmth. Increasing the amount of twist causes an increase in yarn strength by increasing fiber cohesion, but as the twist angle increases beyond an optimum point, strength decreases due to a loss in effective fiber.
and the number of ﬁbers per yarn cross section (yarn number). Hence, twist content alone cannot provide a measure of the twist hardness of a yarn. Twist multiplier and twist factor are proportional to each other and differ only in the units used.
The two are related by Eq 2 and Eq 3: TF 5 k 3 TM (2) k 5 /=L (3) where. How to Grow Roses From Cuttings Fast and Easy | Rooting Rose Cuttings with a 2 Liter Soda Bottle - Duration: Mike Kincaid Recommended for you. Twist Testing of Yarn - Duration: বস্ত্র প্রকৌশল (Textile Engineering) 6, views.
You can twist in either direction. If you hold a length of fiber one end and twist the far end to the left you get an S twist in your yarn. If you twist to the right instead you get a Z twist. Most manufactured single plies are spun with a Z twist.
To ply these Z-spun singles together they are spun with an S twist to give a balanced plied yarn. Special Reserve – Preciosa. Given the nature of single-ply yarns, they work best when avoiding high-abrasion projects like socks, mittens, or gloves.
The friction of normal wear and tear is concentrated onto one single strand of fiber, causing it to weaken and grow thin. Description Application. Twist Tester, is used to get the coefficient of twist, which is a measurement of the level of twist of the yarn, suitable for testing single or plied yarns, equipped with auto stop & reverse for conventional or untwist/re-twist methods, makes yarn twist testing an easy task for textile testing labs or 5/5(2).
on the twist in the yarn. With increase in twist, the yarn strength increases first, reaches a maximum and then decreases. Depending on the end use, two or more single yarns are twisted together to form "plied yarns" or "folded yarns" and a number of plied yarns twisted together to form "cabled yarn".
A 'twisted' cable cast-on for single ply yarns. The cable cast-on technique normally involves wrapping the yarn around the needle in a clockwise direction and then collecting the new stitch onto the left hand needle by moving it through the loop of the stitch from back to front.
Both of these movements remove twist from a single-ply (Z-twist. Digital image analysis techniques in the spatial and frequency domains for twist measurement of yarns are described. A spatial technique is developed to extract the twist angle through the analysis of the yarn core image. Then, a Fourier transformation technique is applied to yarn images to measure the orientation of the fibre on the yarn surface.
Yarn twist is defined as the spiral deposition of the components of a twist is the measure of the spiral turns given to a yarn in order to hold the constituent fibres or threads together – Skinkle. When a strand is twisted the component fibres tend to take on a spiral formation, the geometric perfection of which depends on their original formation – Morton.
Principles of Twist Measuring Methods: The two common methods used in twist measurement are straightened fibre method and untwist/re-twist method. (1) Straightened Fibre Method: This method involves counting of the number of turns required to untwist the yarns until the surface fibres appear to be straight and parallel to yarn axis.
The diameter and twist angle of cotton yarns and jute-blended yarns were assessed by an image analysis technique. The diameter of rotor-spun yarns does not follow the conventional Peirce's equation. The modified equation shows very good correlation (r = ) with measured yarn diameter.
The rotor-spun yarn is found to be 10% bulkier than ring-spun by: When a yarn is incorporated into or removed from a more complex structure, alterations may occur as a result of the plying, untwisting, or raveling operation.
For example, when determining the twist in plied yarn by the procedure for determining original twist, as the plied yarn is untwisted, a comparable amount of twist is reinserted in, or removed from, the single-yarn components. 2) Increase tensile properties of yarn due to twist.
3) The inter-cohesion affinity of fibres increases due to twist and do not open the fibres easily. METHODS OF MEASURING YARN TWIST 1) Single untwist method 2) Fibre straightened method 3) Single twist-untwist method 4) Double twist-untwist method 5) Multiple twist –untwist method