How Much Do You Know About Suture?

- Dec 24, 2017-

 Sewing thread is used to stitch all kinds of clothing materials, with practical and decorative dual functions. Suture quality is good or bad, not only affect the sewing effect and processing costs, but also affect the appearance of the finished product quality. Therefore, especially the general concept of the formation of sutures, twist, twist and strength of the relationship between the suture classification, characteristics and main purposes, the selection of sutures for the introduction, to facilitate business standards and related tests, targeted Determine the suture.

The general concept of line formation

Carded (carding) --- only one end of the yarn and combed.

Combing - yarn combed on both ends of a fiber by a comber with fewer impurities and more straight fibers.

Blended --- two or more different nature of the fiber mixed together yarn.

Single yarn --- spinning machine directly formed, once untwisted will spread, referred to as yarn.

Strands --- two or more than two yarn and twist together, referred to as line.

Sewing thread --- clothing and other sewing products together with the line.

New spinning --- different from the traditional ring spinning, one end of the free end, such as air spinning, friction spinning. Yarn tangle together, no twist.

Yarn --- yarn used to indicate the degree of fineness indicators, the main British imperial count, metric count, special number, denier.

About twist

Definition: Twisting through the fiber structure of a thread causes a relative angular displacement between the cross-sections of the thread and changes the structure of the thread by tilting the straight fiber with the axis. Twisting allows the thread to have a certain degree of strength, elasticity, elongation, gloss, feel and other physical and mechanical properties, expressed in twisting number per unit length, commonly used in the number of turns per inch (TPI) or number of turns per meter (TPM) .

Twisting: 360 degree rotation around the axis as a twist.

Twist direction (S or Z direction): Sliver perpendicular to the axis of rotation formed spiral direction of tilt. The direction of S-twist is the same as the middle of the letter S, that is, the right-hand direction or the clockwise direction. The direction of twist of Z-twist is consistent with the middle of the letter Z, that is, the left-hand or counter-clockwise direction.

The relationship between twist and strength: The twist of a thread is proportional to its strength, but after a certain degree of twisting, its strength decreases. Twist too large twist angle increases, the line of poor gloss, feel bad; twist is too small, hairiness occurs, feel loose. This is because the increase in twist, friction between fibers increases, so that the strength of the line increased. However, when the twist increases, the component force of the yarn in the axial direction becomes smaller and the internal and external fiber stress distribution is uneven, which leads to the inconsistency of the fiber breakage.

In short, the line breaking performance, strength and twist has a close relationship, twist and twist according to the finished and post-processing needs may be, usually Z twist direction.

Suture classification, features and main purposes

According to the raw materials can be divided into natural fiber sewing thread, synthetic fiber sewing thread and mixed thread three categories. 

1. Natural fiber sewing thread

Cotton sewing thread --- cotton fiber as raw material by bleaching, sizing, waxing and other links made of sewing thread. Cotton sewing thread can be divided into no light (or soft), silk and wax light. High strength cotton sewing thread, heat resistance, suitable for high-speed sewing and durable pressing. 

Mainly used for cotton fabric, leather and high temperature ironing clothing sewing, but the disadvantage is the poor flexibility and wear resistance.

Silk thread --- made of natural silk thread or silk thread, has excellent gloss, its strength, flexibility and wear resistance are better than cotton. Suitable for sewing all kinds of silk clothing, high-end woolen clothing, fur and leather garments. 

2. Synthetic sewing thread

Polyester sewing thread --- polyester filament or short fiber manufacturing, with high strength, good elasticity, wear resistance, low shrinkage, good chemical stability. However, low melting point, high-speed easy to melt, plug the eye of a needle, easy to break, should pay attention to the choice of needle. Mainly used in jeans, sportswear, leather products, wool and uniforms, etc., is currently the most used, the most popular sewing thread.

Nylon Sewing Thread --- Pure nylon multifilament yarn manufacturing, sub-filament, staple fiber and elastic deformation line. At present, the commonly used filament yarn, which has a large extension, good elasticity, the moment of elongation of its breaking greater than the same specifications of the cotton three times. For chemical fiber, woolen, leather and stretch clothing sewing. The biggest advantage of nylon sewing thread is transparent, because of this thread is transparent, better color, thus reducing the difficulty of sewing wiring, the development of broad prospects. However, the market is limited to the rigidity of the transparent line is too large, the intensity is too low, easy to float stitches in the fabric surface, combined with high temperature, sewing speed can not be too high. At present, such lines are mainly used as decals, sticks and other hard-to-force parts.

Vinylon sewing thread - made of vinylon fiber, high strength, smooth stitching, mainly for sewing thick canvas, cloth furniture, labor insurance products.

Acrylic sewing thread --- made of acrylic fiber, low twist, brightly colored, mainly used for decoration and embroidery. 

3. Mix sewing thread

Polyester and cotton sewing thread --- It is made of 65% polyester and 35% cotton, and has the advantages of polyester and cotton, high strength, wear-resisting and heat-resisting, shrinking rate, mainly used for cotton, polyester-cotton Various types of clothing, such as high-speed sewing.

Core-spun sewing thread --- filament core, outsourcing of natural fibers, the strength depends on the core, wear and heat depends on the outsourcing yarn, mainly for high-speed and solid clothing sewing.

Suture selection

In the specified conditions, the suture to form a good stitch at the same time maintain the ability of a certain mechanical properties, said sewing, is to assess the overall quality of the suture. According to the sewing material, thickness, organization, color, sewing style, sewing equipment or means, choose the type and specifications matching suture and needle, generally follow the following principles:

1. Coordination with the fabric characteristics

To ensure that the shrinkage, heat resistance, abrasion resistance, durability and other unification, to avoid the line, fabric differences caused by excessive shrinkage. General soft thin material with thin lines, with a small needle, hard thick material with thick lines, with large needle.

2. Coordinate with sewing equipment

Sewing machine selection of left-handed suture, sewing can be twisting, to maintain suture strength.

3. Coordinate with the stitch form

Bag (stretch) Sewing machine used fine cotton, sewing material is not easy to deformation and wrinkling, and the chain stitch beautiful, feel comfortable. Double-stitch should use good extension of the suture. Crotch seam, shoulder seam should be used to secure the suture. Button eye stitch should choose wear-resistant suture.

4. Coordination with the type of clothing

Special-purpose clothing, such as stretch clothing need to use elastic suture, fire service applications heat, flame retardant and waterproof suture.