WEAVING

Weaving is the transformation of yarn into fabric on a loom which interlaces two sets of threads; the warp runs down the length of the cloth and the weft lies at right angles to the warp, crossing the fabric from selvedge to selvedge.

[There are many types of loom but they all operate on the same basic plan. The warp yarns pass from a flanged roller or beam over a whip roller and then horizontally forward; two lease rods separate the warp threads to ensure smooth working and prevent entanglements or sideways rolling over one another. After passing over and under (and under and over) the lease rods, the warp yarns come to the harness which lifts some of the warp and depresses the rest to form a gap known as a “shed”. It is through this gap or shed that the shuttle passes carrying the weft yarn from one side to the other. Shedding is the first of the steps in the weaving sequence.]

The process of weaving consists of five movements:

(a) shedding, or the vertical separation of the warp threads to allow the shuttle to pass through the shed of yarn.

(b) picking, whereby the shuttle carrying the weft is propelled over the race plate through the separated warp yarns.

(c) beating-up, in which the weft yarn is pushed into the “fell” of the fabric by the reed mounted on the oscillating sley or sword.

(d) letting-off, or the release by the warp beam of further threads of warp ready for the next picking.

(e) taking-up, or the winding of the fabric on the cloth beam. The rate of taking-up controls the number of “picks” or weft threads per inch.

Items (a) to (c) are the primary movements in weaving and occur consecutively, whereas the secondary motions (d) and (e) take place simultaneously. The whole, sequence is rapid in actual action, and picks may be inserted at the rate of 250 per minute this is regarded as high speed weaving, low speed may be 85 picks per minute.

The warp threads are often termed “ends” and several thousands of them are lying side by side on the weavers’ beam; the length of yarn on the beam varies according to the type of fabric and may be 3,000 yards with cotton, or as low as 200 yards with woollen and worsted fabrics. The width of the loom may be 18 to 36 inches for the weaving of narrow goods, from 36 to 58 inches for normal goods, up to 156 inches for sheetings, and up to 500 inches for carpets.

The picking motion, for the insertion of welt, is responsible for most of the noise in weaving; it also uses about 75% of the power. The shuttle is propelled from side to side in a somewhat crude manner by a wooden shaft, called a “picking stick”. 

The simple power loom has been subjected to numerous improvements; (a) loom is arrested when a thread breaks, (b) similarly with broken picks, (c) automatic replacement of shuttles when empty, (d) devices are available for changing the weft threads according to their colour for coloured-woven material.