Silk is usually use for textile and spinning become a yarn, from yarn form than continue for waving process become a cloth. On textile industry there are two different kind of process to form a cloth; knitting or waving process, between these process will result a different kind of cloth, knitting will result a t-shirt cloth and waving will produce a wear cloth. The two kind of process just different on the structure of yarn, knitting process arrange in horizontal and vertical structure, while waving process only in vertical structure which are among the vertical yarn is fasten each other.
OK, we talk about silk; silk itself is produced form silk worm (Bombix mori). The silk worm grows and eats of mulberry leaf (Morus sp). To produce a silk fiber, the farmer must look after for thousand worms in a box place with the dimension of about 5 m x 10 m. The silk worm that care come from Japan race or Chinese race, the criteria of this worm has two half circle sign above the body that look like tattoo in human body. On their life, silk worm have a complete metamorphoses, beginning from egg, larva, worm, cocoon and the last become a butterfly. The eggs that just born will in form larva, small with long of about 3 mm. This worm will eat mulberry leaf and sleep, continuously during 3 days and then will change the skin.
As long as their life this worm will change their skin four times, and passes of five eat period called as instar. Each of instar signed by stopping from eats, then sleep, and then changes their skin off the body. After passing of five instars then worm will change to form cocoon for 2-3 days.
This metamorphoses of silk worm become the end of their live period for about 11 days. After this period cocoon will change to butterfly and breeding. Silk fiber can be harvested when worm still inside the cocoon, before the silk can take from the cocoon, the cocoon should be boiled about 10 minutes and the cocoon will die and also for omitted the adhesive material from silk. This silk will spin become yarn.