The History of Denim

Denim is a firm durable twill cotton fabric which woven with colored warp and white filling threads. Frm a technical point of view, denim is a warp faced twill weave fabric. In which coarse and lower yarn count is used. So, it is heavy fabric. Denim is normally used to make jeans, overalls, and other clothing. It was traditionally colored blue with indigo dye to make blue "jeans".

Flow Chart of Denim Production:

Raw materials of denim fabrics:

For producing good quality denim, the conditions should be optimal regarding the quality of all the raw materials and yarn used. For raw cotton and the carded OE (rotor) or ring spun yarns made from it, the following criteria are as follows:

• Denim is a cotton or cotton-polyester blend or other combination of cotton with manmade fiber, durable heavy weight twill weave, and yarn-dyed fabric.
• The minimum staple length: 2.7 cm.
• Short fibres are in a proportion of (less than 12 mm long): under 40%.
• Micronaire value ranges between 4.0 to 4.5
• The values for strength and elongation from uster apparatus for the evenness CV and imperfections must conform at least to the 25% plot.
• Normally count range of denim warp yarns is 50 to 90 tex and weft yarns is 75 to 120 tex; finer yarns as fine as 25 tex in twill or plain weave are often used in denim shirts.
• Twist factor from 4.5 to 5.0 for warp yarns, 4.2 for weft yarns.
• Less yarn hairiness.
• High Yarn strength and uniformity.

Manufacturing of Denim:

The term "Denim" has originated from the city of Nimes in France where "serge de Nimes" was manufactured. Denim is dyed from a vat dye, the Indigo dye, which is applied to cotton fabric in loosely held form in layers. As far as manufacturing process of denim is concerned, it is similar to that of Grey fabric up to the process of weaving with the only difference that in case of Denim Fabric, denim yarn is dyed at the stage of sizing whereas in case of Grey Fabric, the decision regarding dyeing stage depends upon the finished product.

The Open End Spinning Machines have robots on each side which automatically pieces up (repairs broken ends). On a different track, they have another robot that automatically doffs (removes full packages) and starts up a new package. The size and quality of each yarn end are monitored by the Barco Profile System to ensure uniformity. Characteristics of open end Yarn:

• Have Low breaking strength.
• Higher elongation at break.
• Have better mass irregularity at short length.
• Lower IPI value
• High Abrasion resistance
• High stiffness value
• Harder hand feel

In Ring Spinning, the spinning frames receive Roving via a transit system from the roving machine. Yarn is formed from cotton fibers are twisted together after being drafted by passing between three steel rolls and three rubber rolls. The twist is inserted in the yarn by the help of traveller. The relationship between roll speeds, traveler speeds and spindle speeds controls the amount of twist in the yarn. Ends down levels and production information are gathered by the Uster Ring Expert System. The spinning frames automatically doff bobbins full of yarn and send them to package winding.

Characteristics of Ring spun Yarn:

• Ring spinning gets its name from a ring that travels up and down the spindle.
• Yarns are smoother and stronger then yarn made by other spinning technique.
• Fine yarn is obtained from the above method.
• Ring spinning is slower and therefore more expensive than other methods.