• Гідрологія і Гідрометрія
• Господарське право
• Економіка будівництва
• Економіка природокористування
• Економічна теорія
• Земельне право
• Історія України
• Кримінально виконавче право
• Медична радіологія
• Методи аналізу
• Міжнародне приватне право
• Міжнародний маркетинг
• Основи екології
• Предмет Політологія
• Соціальне страхування
• Технічні засоби організації дорожнього руху
• Товарознавство продовольчих товарів

The production of yarns

The first step in making fabric is the production of yarn from fibres. Various methods of spinning are used to do this. Different types of spinning systems are used for different types of fibres.

Natural fibres are harvested and cleaned before they are ready to be made into yarns. The fibres are then combed to untangle them. The combed web of fibres is called a sliver. The sliver is divided into narrower ribbons of fibres called rovings. The roving is generally pulled and twisted to form a single yarn. Because the ends of the fibres stick out from the edges of the yarn, it looks hairy.

If the fibres are combed more than once, it is called carding. Yarns made from carded fibres are smoother as fewer fibre ends are left sticking out of the yarn. For example, high quality wool fibres are combed and corded to make fine worsted yarn. (See Picture “carding machine”.)

Yarns are single strands, i.e. they are one-dimensional. In order to manufacture fabric from yarns the single strands must be combined so that the structure becomes two-dimensional. This is achieved in both weaving and knitting but, before either of these procedures takes place, yarns can be processed to produce the particular properties required in the final fabric.

Staple fibres have to be twisted together to form a yarn. Twist can be put into a yarn:

- clockwise where the fibres twist to the right;

- anticlockwise where the fibres twist to the left.

Clockwise twist corresponds to the shape of the letter S and is called S-twist. Anti-clockwise twist corresponds to the shape of the letter Z and is called Z-twist.

Particular properties in the yarn can be achieved by applying different amounts of twist to bind fibres together. For example, to make a yarn thicker or stronger, two or more single yarns may be twisted together. Single yarns twisted together in this way make a plied yarn. Two single yarns twisted together are called two-ply, four singles twisted together are called four-ply etc. Plied yarns are stronger and can withstand the pressures exerted on them during weaving better than single yarns which tend to fray. A small amount of twist will give a soft yarn but as the amount of twist is increased the softness decreases. This can be useful, for example, when considering drape. A yarn with a high amount of twist will produce a fabric which does not drape well and therefore would not be suitable for making curtains or anything which requires good draping quality.

In addition to increasing the strength of a yarn, plying makes it possible to produce a variety of yarns, e.g. fancy yarns. These can be produced in several ways, for example by blending fibres of different colours and spinning them as one yarn, by printing or dyeing a pattern on to the sliver and so on. Other methods of producing fancy yarns include twisting together two or more yarns which are different in some way, e.g. colour, softness, thickness etc. The amount and direction of twist may be altered to produce an uneven effect. However the effect is achieved, fancy yarns give colour and texture and can be very decorative. Every fancy yarn has a specific name which identifies how it was produced, the fibres from which it was made and its appearance.

Most fancy yarns are based on two or more plies, with one ply being the core, another ply giving the special effect and an additional ply which holds the other two together.

III Answer the questions

1. What is the first step in making fabric?

2. What has to be done with natural fibres before spinning?

3. What process allows getting smoother yarns?

4. Fibres of which type have to be twisted together to form a yarn?

5. How can particular properties in the yarn be achieved?

6. What does the amount of twist influence?

7. What does plying make possible?

8. What is fancy yarn?

9. What effects do fancy yarns give?

10. How is fancy yarn produced?

IV Complete the sentences with the words from the text and translate them

1. The fibres are combed to... .

2. The roving is pulled and ... .

3. High quality wool fibres are combed and ... .

4. To manufacture fabric from yarns ... .

5. Clockwise twist corresponds ... .

6. ... of the letter Z and is called Z-twist.

7. Two single yarns twisted together are ... .

8. ... may be altered to produce an uneven effect.

9. ... has a specific name which identifies ... .

V Read the words from the Ex.1. Look through the text again and find out the sentences with them. Make up your own sentences with these words

VI Give definitions to the words:a sliver, roving, carding, one-dimensional yarn, two-dimensional yarn, a plied yarn, fancy yarns

VII Translate the sentences into English

1. Виробництво полотна починається з виробництва волокна та пряжі.

2. Природні волокна спочатку необхідно зібрати та очистити.

3. Щоб отримати більш гладку пряжу, волокна треба прочесати.

4. Пряжа повинна пройти спеціальну обробку, щоб полотно мало потрібні властивості.

5. Штапельні волокна можуть бути скрученими за годинниковою стрілкою або проти годинникової стрілки.

6. Полотна, що погано драпіруються виготовляються з пряжі з високим ступенем скручування.

7. Кілька пасем волокна утворюють кручену пряжу.

8. Декоративну пряжу отримують через скручування пасем в різних напрямках і з різною щільністю.

Читайте також:

1. Apparel Production
2. C. Evolution of textile production
3. Fabrics production and their properties
4. III. Manner of noise production and the type of obstruction
5. Information technologies in production
6. Inspection of Production Facilities and Production Samples
7. Kazakhstan to Launch Its Own Infant Food Production
8. Knitwear production methods
9. Methods of fabric production
10. My Future Speciality: Production Technologies of Building Constructions and Elements
11. PEOPLE INVOLVED IN FILM PRODUCTION
12. PRINCIPLES AND PROCESS OF POLYMERISATION IN PLASTICS PRODUCTION

Переглядів: 447