1. The Manufacture of Woolen Yarn
We have taken the worsted industry first, not because it is necessarily any more important than woolen manufacture, but because its processes are more complicated, and therefor, if we have gained a certain amount of familiarity with them, we are able to take up the sister industry in a more abbreviated manner. Although, at the present time, the demand for worsted materials is a great deal heavier than the demand for woolens, the woolen industry is by far the older of the two, and may rightfully claim that the worsted branch is really an off-shoot of its tree. Moreover, while broadcloth and similar material no longer enjoy their erstwhile popularity, there is still a tremendous demand for other products of the woolen industry such as blankets, flannels, overcoatings, etc. And we must bear in mind that most of the cheaper clothing materials are woolens.
Raw Material
In the sorting of wool we saw that the shorter staples were classed as clothing wools. To these must be added the noils from worsted combing, yarn waste, and wool reclaimed from off-sorts, as well as wool extract made from rags, before we have the raw material for the woolen industry.
Scouring
Whereas we found that combing wool had to be left in the grease until it could be carded immediately after scouring, the maker of woolen yarn will buy wool that has been scoured months before. Most of the wool that is scoured by or near the growers finds its way into the woolen industry for this reason. The scouring given to clothing wool varies only in that it is more violent than that given to combing wool, and in that it is frequently augmented by carbonization to remove vegetable matter.
Mule Spinning
Blending
The first process after scouring is blending. When the desired mixture of various grades, kinds, and colors of wool, wool extract, or cotton has been effected, the resulting heterogeneous mass is put through the first of several carding processes.
Fibres not parallel as in Worsted
From now on the desire of the woolen yarn manufacturer is diametrically opposed to that of the worsted comber. He wants to open out the fibres, but he wants them to lie in all directions. He does not want uniformity. He wants just the opposite. His yarn must have a certain amount of strength, but it must have, first of all, felting properties, so that when the cloth is finished the various threads will merge and interlock. As might be expected, therefore, the carding process is very much more violent.
Carding
Condenser
The blend is first put through a fearnought which might be described briefly as the most pitiless member of the card family. It is also known as a tenter-hook-willy, from the reversed position of its teeth. From this machine the wool goes through the card proper, which is similar to the worsted card except that the rollers go in opposite directions, instead of in the same directions. Here, again, the doffer lifts the wool off in a continuous filmy sheet and delivers it to the condenser. The sheet is not simply drawn through a funnel into a single thick sliver, but is forced between rollers into two leather rubbing aprons which by pressure and friction reduce it to a series of small soft flabby slivers, having just enough adhesiveness to permit of mule spinning.
Burling and mending
The fibres in these slivers may be of all lengths and degrees of fineness, and they lie in all directions.
There are now no elaborate drawing or combing processes. All that remains to be done before we have a weavable woolen yarn is a certain amount of twisting and attenuation. Both these results are obtained at once in the mule.
Mule Spinning
In a woolen mule the spools of sliver are placed in a fixed frame, and the sliver passes between a pair of rollers to the spindles. These stand, slightly inclined backwards, in a long row upon the movable carriage. At first the spindle tips are close to the rollers. The sliver is paid out, and at the same time the carriage bearing the revolving spindles retreats. During this time no yarn is wound on the bobbins, but the slivers are being twisted. Then the rollers cease to pay out sliver, the carriage moves out a little further, and the spindles rotate faster, so that the yarn is being twisted and stretched. When sufficient twist has been imparted the carriage moves back again and the spindles wind up the twisted yarn on to the bobbins. This, briefly, is the operation of the mule. There are a great many intricate devices in this machine which deserve attention, but which hardly fall within our scope. All that remains now is to wind the yarn on spools, or skein it, before it is ready for the weaver.