How Silk is Manufactured?

The first stage of silk production is the hatching of the silkworm egg in a controlled environment such as an aluminum box, which is then examined to ensure they are free of disease. The female deposits 300-400 eggs at a time. In an area the size of an A4 page around 50 moths would deposit more than 20,000 eggs, each about the size of a pinhead. The female dies almost immediately after depositing the eggs and the male lives only a short time after. The adult silkworm possesses rudimentary mouthparts and does not eat during the short period of its mature existence. These disease-tested eggs are raised in temperature and disease-controlled conditions. They are fastened to a flat surface by a gummy substance secreted by the female. 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 huge amounts of cut up mulberry leaves during which time they are left to molt (shed its skin) four times. The larvae may also feed on Osage orange or lettuce. Larvae fed on mulberry leaves produce the very finest silk. The larvae will eat 50,000 times its initial weight in plant material.

After it has reached its maximum growth at 7.5cm at around 4-6 weeks it stops eating, changes color and attaches itself to a compartmented frame, twig, tree or shrub in rearing houses to spin their silk cocoons over a 3-8 day period. This is period is termed pupating. Steadily over the next four days the silkworm produces a fine thread by making a figure of eight movement some 300,000 times, constructing a cocoon in which it intends to spend the chrysalis stage where it is in a state of sleep and casting off of skin. After this the pupae begins the sixteen days, which would normally result in the miracle of transformation to a winged being - the moth. However, if the pupae (chrysalis) remain alive it will begin to secrete an alkali, which eats its way through the cocoon ruining the silk threads. So, as the cocoons are completed the pupae are killed or 'stifled'. The amount of usable silk from each cocoon is small. Around 500 silkworms or 80 kg of cocoons and 200kg of mulberry leaves are required to produce 1 kg of raw silk.

The various steps of silk production process include:

1) Raising silkworms & harvesting cocoons
2) Thread extraction
3) Bleaching and Dyeing
4) Spinning
5) Weaving