3. Weaving Gray Goods
Principle of Weaving
The modern power loom represents one of the most remarkable achievements of industrial development. Into its perfection have gone the inventions and improvements of centuries, and volumes could, and have been written on the subject of modern weaving. Nevertheless, the old-fashioned hand-loom has not yet gone out of existence, and still finds its use in the development of new designs.
Spooling
Weaving is, of course, the process whereby yarn is made into cloth, and its fundamental principle is that of the warp and weft structure. In its simplest form this means that a series of threads are stretched parallel to each other, thereby forming a warp. A second thread, called the weft, is then passed over the odd and under the even warp threads, and back again under the odd and over the even. In this way a cloth fabric will gradually be built up. In most cases the process has become considerably more complicated than this, but there are even now certain materials, such as calico, which retain the elementary weave. The actual weaving, that is, the passing of the shuttle carrying the weft thread over and under the warp threads, has now been reduced to an entirely automatic process, even with the most complicated designs, but the preparatory work still entails a large proportion of hand labor.
The Creels
Spooling
The first operation consists of winding the yarn from the bobbin on to spools, each containing the same length of yarn. This must be done with care or considerable waste will result.
The Creel
The next step is to place these spools in a rack or creel where they fit on glass bearings so that they may be arranged in the proper order and run through the warper on to the section beam. The latter is a large roller several of which are combined to form a beam. The beam is the name given to the roller which is placed in the loom to deliver the warp threads.
Sizing
In order both to strengthen the warp threads and to make them smoother for weaving it is usual to apply some starchy or glutinous substance to them. This operation, which is performed in a machine called the Slasher, is termed yarn sizing, and consists of running the threads through a bath of preparation and then drying them quickly on a large steam-filled drum or can. One slasher will do enough work for 200 to 500 looms.
The Slasher
Healding
Since it is necessary that the warp threads may be lowered or raised in various combinations to allow the passage of the shuttle, each warp thread must be passed through an eye in the centre of a harness wire. Where, for instance, the warp is to be raised and depressed in three even sections there will be three harness frames, each fitted with enough heald-wires to accommodate one-third of the number of threads in the entire warp. In the Jacquard loom, used for intricate patterns, each warp-thread is separately controlled. The passing of the ends of the warp through their proper harness wires is a delicate and skilfull operation known as healding, or drawing-in. At the same time that this is done the threads are passed through individual stop-motion wires, relaxed tension on any one of which will bring the loom to a stop.
Drawing In
Reeding
Closely connected with drawing-in, is the final step in the preparation of the warp, and this is called reeding or sleying. In order to keep the warp threads in proper position during weaving they are passed through the wires of what looks like a comb with a strip across the open ends. This, the sley or reed, is attached to the batten on the loom and serves in addition to drive home each weft thread after the shuttle has passed.
Warp Tieing
When the loom has devoured all the warp threads contained on one beam, all that is necessary, if the pattern is to be continued, is to tie the ends of the old warp to the ends of the new, and this is accomplished with marvelous accuracy by a little machine built on the same principle as the Barber Knotter. This avoids drawing-in a second time.
Weaving Shed of Power Looms
The Power Loom
When the preparatory processes have been completed the actual weaving is done, practically without human agency. The shuttle flies back and forth at the rate of from one to two hundred picks per minute, and when its thread is exhausted it drops out and, in the automatic loom, is immediately supplanted by a fresh one. The harness frames jerk up and down, forming and reforming the V shaped shed through which the shuttle passes; and after each pick the batten drives home the new thread into the ever-growing stretch of cloth. Like the film in a kodak, where a roller at one end gives out plain paper which is rolled up at the other end as a magic sheet of pictures, so in the loom the homely warp threads are rolled out at one end, while the roller at the other extreme winds up smooth gray cloth.
We have now made yarn out of cotton, and unbleached cotton cloth, or gray goods, out of our yarn. All that remains before the fabric goes to the finisher is an inspection for imperfections and their removal where possible, usually by hand.