YARN TWIST AND SEWING THREAD

YARN TWIST AND SEWING THREAD

YARN TWIST:-

    Twist is the spiral arrangement of the fibres around the arts of the yarn. The twist binds the fibres together and also contributes to strength of the yarn. The amount of twist inserted in a yarn defines the appearance and the strength of the yarn. The number of twist is referred to as turns per inch.

       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 fibers or threads together

TYPES OF TWIST:-

ü S-twist

ü Z-twist

 

S-twist:-

       S-twist yarn is a yarn spun counter-clockwise and is normally used to create right-handed twill, while Z-twist yarn is used for left-handed twill. By opposing the direction of the yarn and the direction of the twill, the finished material is softer than fabric created with a corresponding yarn and twill weave.

Z-twist:-

       Z-twist. When a twisted yarn is held vertically, the individual filaments are appearing in this case as the diagonal in the letter "z". The same can apply if several yarns have been twisted together: their combined twist can again appear as the diagonal of the letter "z".

TWIST DIRECTIION:

       The direction of the twist at each stage of manufacture is indicated by the use of letters S or Z in accordance with the following conversation:

       A single yarn has S twist if, when it is held in the vertical position, the fibers inclined to the axis of the yarn conform in the direction of the slope to the central portion of the letter S. Similarly the yarn has Z twist if the fibres inclined to the axis of yarn conform in the direction of slope to the central portion of the letter Z.

       The Amount of Twist: In B.S. 946: 1952 it is started that the amount of twist in a thread at each stage of manufacture is denoted by a figure giving the number of turns of twist per unit length stage. It affects the characteristics and properties of a yarn including appearance, behavior and durability.

       The amount of twist is an important factor in finished consumer goods. It determines the appearance as well as the durability and serviceability of a fabric. Fine yarns require more twist than coarser yarns. Warp yarns, which are used for the length wise threads in a woven fabric, are given more twist than filling yarn which is used for cross wise threads.

The amount of twist also depends upon the types of the fabric to be woven:

1.  Yarns intended for soft surfaced fabric are given slack twist. They are called as soft twisted yarns.

1.  Yarns intended for smooth surfaced fabrics are given optimum twists. Such twisted yarns contribute strength, smoothness and elasticity.

2.  Yarns intended for crepe fabrics are given maximum amount of twists.

Effect of yarn

•    Yarn strength
• Handle
• Moisture absorption
• Wearing properties
•  Aesthetic effect
•  Crepe effect
•  Curling effect

SEWING THREAD

SEWING THREAD TYPES ANDPROPERTIES

INTRODUCTION:

    Sewing thread is an important trimming which are vastly used in readymade garments sector. Sewing thread contains some properties.

Cotton threads:

       Cotton thread has very little “give” and tends to break easily. However, it’s a good choice when sewing delicate fabrics or for lingerie sewing projects. Choose a medium thickness cotton thread for working with lightweight to medium-weight cottons, linens and rayon’s.

    Polyester thread is a true all-purpose thread, and it’s a good choice for most sewing projects, both machine- and hand-sewn. The thread has some give to it, so it won’t break when you are working with stretchy knits. Polyester thread often has a wax silicone finish that allows it slip through the fabric easily.

Heavy-Duty Thread:

       Heavy-duty thread is also a polyester thread, but the weight of the thread is not suitable for most garment sewing projects. It is, however, the perfect choice when sewing upholstery and canvas, so you might find yourself reaching for it when you’re tackling home décor sewing projects.

Silk thread

       Silk thread is very fine. It’s also flexible and won’t leave holes, so it makes an excellent choice for bastling thread. It’s also great to use when sewing silk or wool.

Wool thread:

       Wool thread is not used for regular use. When sewing garments, as it trends to be used for embroidery projects, but it is an extremely strong thread that’s good choice when working with heavy fabrics like wool and canvas.

Metallic thread:

Metallic thread is often featured on handbags; it is available in gold, silver and copper verities. It’s used often in machine embroidery, and would be a good choice if a thread with a little flair for topstitching.

Designer thread:

These are typically made from combining two or more types of thread, like a silk and rayon blend.

Properties:

       There are different key properties of sewing thread which are mentioned in the following:

1.  Tensile strength,

2.  Tenacity,

3.  Loop strength,

4.  Loop strength ratio,

5.  Minimum loop strength,

6.  Elongation at break,

7.  Stress strain at break,

8.  Elasticity,

9.  Shrinkage,

10. Abrasion resistance,

11. Color fastness.

1.Tensile strength:

       The minimum load which is needed to break the sewing thread is termed as tensile strength of that thread.

2. Tenacity:

       The ratio of tensile strength and thickness or count of sewing thread is known as tenacity. Strength and quality of various count thread are verified by tenacity. Tenacity is denoted by gm per tex or gm per denier in textile and apparel industry.

3. Loop strength:

Thread has minimum strength in its loop position and the minimum load needed to break the loop is termed as loop strength. It is deeply related with stitch strength of a thread.

4. Loop strength ratio:

       The ratio of sewing thread tenacity and loop strength of that thread is termed as loop strength ratio.

5. Minimum loop strength:

       The loop strength of weaker loop is termed as minimum loop strength. It is used to determine the performance of sewing thread in the stitch.

6. Elongation at break:

       Elongation at break is the extension od sewing thread at breaking point. It is expressed in percentage. It is too much important for extensibility of seam.

7. Stress strain curve:

       Stress strain curve iis the drawing curve of tenacity which opposes the elongation of sewing thread. It has great importance to compare the value of two threads.

8. Elasticity:

       Elasticity is the property by means of which the sewing thread returns back to its original position when deforming force is released.

9. Shrinkage:

       The dimensional change of sewing thread after washing with or heat is called shrinkage. Shrinkage is expressed as percentage. Due to the shrinkage of threads, seam pucker is occurred.

10. Abrasion resistance:

       Abrasion resistance is the frictional resistance of one sewing thread to another. It has great importance to determine the sewing performance of thread which is measured by using special machine and method.

11. Color fastness:

       Color fastness is very important factor for the sewing thread. The color durability of sewing thread against sunlight and wash must be as like as garments.