The silk must be woven into a fabric before the process is complete and the product can be sold. The procedure involves the interlacing of two yarn systems that run perpendicular to one another.

Preliminary weaving processes:

In general, weaving involves using a loom to interlace two sets of threads at right angles to each other: the warp which runs longitudinally and the weft (or woof) that crosses it. One warp thread is called an end and one weft thread is called a pick. The warp threads are held taut and parallel to each other in a loom.

Silk threads are held on bobbins on a frame called a creel. High-capacity creels are used in power looms. A horisontal creel can hold up to 400 bobbins. The central opening allows the worker to inspect and organise bobbin threads. Gathered threads are fed through a reed before being wound onto the warping drum.

Depending on the width or ends of the fabric, the drum will prepare a specific number of sections after each one is made. The width of the fabric necessitates more warping machine sections and threads. A 400-bobbin creel, for instance, will have 400 threads in each bobbin.

Small warping devices are used in handlooms. Handloom weavers often make their own warp by combining threads into sections or balls and then warping a sheet.

Premium-grade silk fabric. (Source: pexels by LoggaWiggler)

What is beaming?

Weavers use a process known as beaming to transfer sectional warp from the warp drum to the warp beam. In order to draw the reeds through the loom, the ends must be passed over a whip role, over and under the lease rods, and finally through the current of the heddle eyes of the respective heddles.

Spinning a pirn

A pirn holds the strands and fits inside the shuttle that takes the weft strands through the warp strands for the actual weaving. The pirns are made small enough to fit in the shuttle’s mounting system. The pirns used in power looms are typically larger and hold more yarn. Power loom weaving, then, requires a pirn winding machine. Automatic or manual pirn winding machines are available.

The thread tension and coil distribution on an automatic pirn winding machine can be precisely adjusted, and the machine can immediately stop working if a thread breaks. The greater the yarn content and the more precisely packaged the pirn, the less often the shuttle will need to be stopped to replace the pirn, resulting in greater weaving efficiency.

Drawing

This is executed using a warp beam. The strands are threaded over a whip roll, under the lease rods, and into the right heddle eye before being drawn through the reeds’ dents. Reeding is the process of creating threads from reed.

Gating

Gating refers to the process of adjusting the loom so that the warp beam, heddle shaft, and reed are all at the correct height and angle.

(Source: pexels by Narasimhan AVPL)

Primary and secondary motions are involved in the actual weaving mechanism

  1. Primary motions

Movement of shedding

When a warp is divided into upper and lower thread systems, the shuttle can move through the resulting gap, drawing the weft thread between the two sets of warp threads.

Power looms do it automatically, while hand looms require manual intervention, and handloom shuttles are smaller.

The motion of picking

The movement of the shuttle between the sets of thread is called picking. As the shuttle travels across the loom, it releases a pirn of filling yarn. During a pick, one shuttle travels the length of the loom.

Beaten up

This is the process of pushing the weft tight to the already woven part of the cloth. A slay moves forward to beat the final weft pick and then back to clear the way for a shuttle in a shed.

Diagram of the weaving procedure using a pit loom. (Source: Mahesha, Silk weaving)

  1. Secondary motions

Releasing Pressure

The let-off motion is set up to let the warp out of the weaver’s beam at a constant rate, keeping the warp tension steady as the weaving progresses.

Motion of pick up

The take-up motion is what winds the cloth onto a roller after it has been withdrawn from the weaving area at a constant rate to achieve the desired pick-spacing (picks/cm). The ratio of ends to picks per centimetre is established by the take-up motion.

Components of a loom and their respective functions. (Source: Mahesha, Silk weaving)

Different looms

Handloom

A handloom is a simple, usually handmade weaving apparatus. Two distinct categories of handlooms exist:

  1. The frame loom is a bit more upto-date than the pit loom. It may be set up in any regular home. When compared to pit looms, frame looms will take up less room.
  2. The traditional loom is a pit loom, which is more robust and produces fewer vibrations during the weaving process. About five sarees can be made from a single ball of warp prepared for a pit loom. The weft is put into the weaving process in increments of one saree length using either a throw shuttle or a fly shuttle. The rate of production is really low.

An efficient weaver can produce about 3 metres of plain cloth every day. The leader of the family will do the actual weaving on the loom, while the rest of the family will undertake the preparatory work (warp and weft preparation).

Reeled silk is wound onto a wooden spool. (Source: pexels by Jana)

Power loom

Power looms come in two distinct varieties: The first type is an overpick, while the second is an underpick. Weaving silk is best done in an underpick.

If the weavers warp beam (which contains longer warp) is prepared in another part of the warping machine, weaving can continue for months. Power looms have one weaver and larger pirns to increase yarn capacity and decrease the frequency of shuttle replacement.

The average daily output is 10 to 15 metres. High-quality yarn is essential for weaving on a power loom. Since the warp ends are tensioned while weaving, charaka silk is typically used for the weft while cottage basin or filature silk is used for the warp.

A weaver at her pit loom, threading her throw shuttle with a silk string. (Source: pexels by aiworldexplore)

Automatic looms

In the same way that some developed nations use automatic looms for cotton and synthetic weaving, they also do so for silk.

Automatic looms have a number of convenient features, including automatic let off, pirn changing, break stoppage at the warp end, and break stoppage at the weft end.

By automating these processes, weavers can handle anywhere from six to ten looms at once. The output increases. Fabrics like sarees, saris, and checks predominate.

References

Mahesha, H.B. (no date) Silk weaving, Weebly. Available at: https://hbmahesh.weebly.com/uploads/3/4/2/2/3422804/silk_weaving.pdf

Textile weaving, https://en.wikipedia.org/wiki/Weaving.