Silk is produced by various insects, but by far the largest quantity comes from the silkworm 'Bombyx Mori'. This is the silk worm, which feeds on mulberry leaves and forms a cocoon of Silk before pupating. The threads from several cocoons are subsequently unwound together to form a single strand of raw silk. This fine thread is the basic component of all Silk yarn and fabric. Some of the gum, which the silkworm uses to hold the cocoon together, remains to assist the delicate fibre during processing. It is subsequently washed away.
Weaving is the operation that creates a fabric by interlacing the warp yarns (lengthwise) and the weft yarns. Weaving is carried out on looms, after a series of preliminary operations including:
In the past twenty years, enormous strides have been made in improving not only the machines involved in the preparation of weaving, but in the loom itself. Non-stop weaving has been made possible by the introduction of automatic pirnchanging. And there are now shuttleless looms, (more properly called weaving machines). These machines use lances, or projectiles, or a jet of compressed air to shoot the weft-yarn between the warp-yarns, instead of the traditional shuttle, and at vastly higher speeds. This increased automation also meant that one weaving-worker can now look after 20 looms at the same time, instead of only 4 traditional looms. This has consequently led to much greater yield and productivity.
Some of the modern weaving machines are large enough to weave fabrics 3 metres wide. In addition to their greater speeds these machines also offer the advantage for the weaver of enabling him to divide this large width into several smaller widths, for example 3 times 90 centimetres.
Although modem weaving machinery has made enormous progress, certain specific types of silk can only be made on ordinary looms, as they are too complex to be woven on highly-automated machines, running at very high speeds. This is notably the case for high-novelty fabrics, and even more so for the reproduction of traditional fabrics used for wallcoverings, upholstery etc.
Many of these fabrics are produced on Jacquard looms, called after their Lyonnais inventor, who in 1801 perfected the existing system of patternweaving, by the use of perforated cards. The Jacquard loom makes it possible to weave intricate and multi-coloured patterns directly into the fabric, and thus create highly elaborate and handsome fabrics.
As soon as they come off the loom, the fabrics are thoroughly inspected so as to eliminate any defects that may have occurred during weaving.