Manufacturing Process of Silk

Presented by: Kazi Sazed SalmanID No: 111-23-130Textile Engineering

Silk is a kind of protein fibre which is obtained form silkworm that is the caterpillar named Bombex mori. China is famous for silk producing. As well as many other countries also produce silk now. Silk producing process started several millennia ago in China. This silk production or manufacturing process is known as sericulture.

The silkworm is the main raw material of silk production. It is a caterpillar which makes cocoon and this cocoon is used to make silk filament. These caterpillars eat mulberry leaves and makes filament of silk. So the mulberry leaves are also essential in sericulture.

Introduction

Step 1: Breeding & Feeding Silkworm

 The first stage of silk production is the hatching of the silkworm eggs, which takes place in a controlled environment. The female lays 300 to 400 eggs at a time, each about the size of a pinhead. The female dies almost immediately after depositing the eggs. The larvae hatch in about 10 days and are about 0.6cm long. Once hatched they are placed under a layer of gauze and fed large quantities of mulberry leaves. After four to six weeks, when the larva has achieved its maximum growth, it stops eating, changes colour and attaches itself to a compartmented frame, twig, tree or shrub in the rearing house ready to become a chrysalis. Silkworms in

scuttleSilkworms eating mulberry leaves

Step 2: Spinning the CocoonOver the next four days the silkworm spins a fibrous cocoon around itself. The cocoon is secreted as a continuous silk fibre up to a mile long from special glands in the silkworm's head. If the adult moth were allowed to emerge from the cocoon naturally, it would secrete an alkali, which would eat through the cocoon. Therefore the silkworms are killed by heat to preserve the silk cocoon, by immersion in boiling water, steaming or drying in an oven. Only enough adult moths are allowed to emerge to ensure the continuation of the species.

A silkworm making cocoon

Alive silkworm cocoons Boiled silkworm cocoons

Step 3: Sorting Cocoons & Reeling Fillament

The filature is the factory in which the cocoons are processed into silk thread. In the filature the cocoons are sorted by various characteristics, including color and size, so that the finished product can be of uniform quality. The cocoons must then be soaked in hot water to loosen the sericin.Reeling may be achieved manually or automatically. The cocoon is brushed to locate the end of the fiber. It is threaded through a porcelain eyelet, and the fiber is reeled onto a wheel. Meanwhile, diligent operators check for flaws in the filaments as they are being reeled.

Manual & mechanical way of processing cocoons & reeling fillament

Final step: Finishing Silk Fabrics

After degumming, the silk yarn is a creamy white color. It may next be dyed as yarn, or after the yarn has been woven into fabric. The silk industry makes a distinction between pure-dye silk and what is called weighted silk. In the pure-dye process, the silk is colored with dye, and may be finished with water-soluble substances such as starch, glue, sugar, or gelatin. To produce weighted silk, metallic substances are added to the fabric during the dying process. If weighting is not executed properly, it can decrease the longevity of the fabric, so pure-dye silk is considered the superior product. After dyeing, silk fabric may be finished by additional processes, such as bleaching, embossing, steaming, or stiffening.

Fresh silk: Creamy color Dying silk with color

Dyed silk of various color

Some Pictures of Making Silk Cloth

By loom By machine

Reference from:

http://www.madehow.com/Volume-2/Silk http://vegansociety.com/animal/silk

THANK YOU

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