Textiles Part 5

=Weaving Processes.= In order to understand the different kinds of weaves it is necessary to know, or at least to understand, the process of forming cloth, called weaving. This is done in a machine called a loom. The princ.i.p.al parts of a loom are the frame, the warp-beam, the cloth-roll, the heddles, and their mounting, the reed. The warp-beam is a wooden cylinder back of the loom on which the warp is wound. The threads of the warp extend in parallel order from the warp-beam to the front of the loom, and are attached to the cloth-roll. Each thread or group of threads of the warp pa.s.ses through an opening (eye) of a heddle. The warp threads are separated by the heddles into two or more groups, each controlled and automatically drawn up and down by the motion of the heddles. In the case of small patterns the movement of the heddles is controlled by "cams" which move up the heddles by means of a frame called a harness; in larger patterns the heddles are controlled by harness cords attached to a Jacquard machine. Every time the harness (the heddles) moves up or down, an opening (shed) is made between the threads of warp, through which the shuttle is thrown.

[Ill.u.s.tration: A SIMPLE HAND-LOOM

Showing frame, warp beam, cloth-roll, heddles, and reed]

The filling thread is wound on a bobbin which is fastened in the shuttle and which permits the yarn to unwind as it pa.s.ses to and fro.

As fast as each filling thread is interlaced with warp it is pressed close to the previous one by means of a reed which advances toward and recedes from the cloth after each pa.s.sage of the shuttle. This is done to make the cloth firm. There are various movements on the loom for controlling the tension of the warp, for drawing forward or taking up the cloth as it is produced, and for stopping the loom in the case of breakage of the warp thread or the running out of the filling thread.

Weaving may be performed by hand in hand-looms or by steam-power in power-looms, but the arrangements for both are to a certain extent the same. A great number of different kinds of power-looms are manufactured for producing the various cla.s.ses of textiles in use at the present time. These looms are distinguished by the name of the material which they are designed to weave, as the ribbon-loom, blanket-loom, burlaps- and sacking-loom, plush-loom, double-cloth loom, rug-loom, fancy cotton-loom, silk-loom, worsted-loom, etc.

Weaving is distinct from knitting, netting, looping, and braiding, which are operations depending on the interlacing of a single thread, or single set of threads, while weaving is done with two distinct and separate sets of threads.

[Ill.u.s.tration: MAIN WEAVE ROOM

1. Warp beam containing warp.

2. Lease Rods.

3. Harnesses.

4. Dobby Head motion to lift harnesses.

5. Jacquard Head motion.

6. Cards containing design--working in connection with Jacquard Head motion.

7. Whip Roll.]

=Cla.s.ses of Weave.= The character of the weave offers the best basis for cla.s.sification of woven goods. Nearly all the varieties of cloth may be cla.s.sified from the following weaves:

(1) Plain-weaving, (2) Twill-weaving, (3) Satin-weaving, (4) Figure-weaving, (5) Double-cloth-weaving, (6) Pile-weaving, (7) Gauze-weaving, (8) Lappet-weaving.

=Plain or Homespun Weave.= Plain cloth is the simplest cloth that can be woven. In this weave one series of threads (filling) crosses another series (warp) at right angles, pa.s.sing over one and under one in regular order, thus forming a simple interlacement of the threads.

This combination makes a strong and firm cloth, but does not give a close or a heavy fabric, as the threads do not lie as close and compact as they do in other weaves. In plain cloth, if not fulled or shrunk in the finish, the result is a fabric perforated with large or small openings according to the size or twist of yarn used. If heavy or coa.r.s.e threads are used the perforations will be large; if finer threads, the perforations will be smaller.

This weave is used in the production of sheeting, muslin, lawn, gingham, broadcloth, taffeta, etc. In plain weaving it is possible to produce stripes by the use of bands of colored warp, and checks where both warp and weft are parti-colored. This weave is commonly used when the cloth is intended to be ornamented with printed patterns. In weaving cloth of only one color but one shuttle is used, while for the production of checks, plaids, etc., two or more shuttles are required.

[Ill.u.s.tration: GIRL DRAWING EACH THREAD OF WARP THROUGH THE REED AND HARNESS READY TO BE PLACED ON LOOM

A, warp beam. B, warp. C, harness frame]

=Twill Weave.= A twill weave has diagonal lines across the cloth. In this cla.s.s of weaves the filling yarn or threads pa.s.s over 1 and under 2, or over 1 and under 3, 4, 5, or 6, or over 2 or 3 and under 1, 2, 3, or 4, or over 4 and under 4, 3, 6, etc. Each filling thread does not pa.s.s under and over the same set of warp threads, as this would not give the desired interlacings. Instead the order of interlacing moves one thread to the right or left with each filling thread that is woven. If there are the same number of threads to an inch in warp and filling, twill lines will form an angle of 45 degrees; if the warps are closer together than the filling, the angle will be steeper; if the filling threads are closer together the lines will approach more nearly the horizontal. Different effects are obtained in patterns by variation in the sizes of the yarn and twist, by the use of heavy threads to form cords, ribs, etc., and by the mixture of vari-colored materials in the yarn. Often one form of twill-weave is combined with another to produce a fancy twill-weave. The object of the twill-weaving is to increase the bulk and strength of a fabric, or to ornament it. The disposition of the threads permits the introduction of more material into the cloth, and hence renders it heavier, and of closer construction than in the case of plain-weaving.

=Satin Weaves.= The object of a satin weave is to distribute the interlacings of the warp and filling in such a manner that no trace of the diagonal (twill) line will be seen on the face of the cloth. In weaving a satin design the filling thread is made to pa.s.s under 1 and over 4, 7, 9, 11, or more if a larger plush satin is required. The raising of the warp end to allow the filling to pa.s.s under is done in such a way as to prevent twill lines from showing in the cloth. The result is that practically all of the filling is on the face of the cloth. This is called a filling-face satin weave. A warp-face satin weave may be produced by reversing the order; in this case practically all of the warp is brought to the face of the cloth. In this way a worsted warp and a cotton filling might be woven so that practically all of the warp would show on the cloth, and give it the appearance of a worsted fabric. A number of cla.s.ses of silk goods are made in this way, with a silk filling covering a cotton warp.

This weave produces an even, close, smooth surface, capable of reflecting the light to the best advantage, and having a l.u.s.trous appearance which makes it resemble satin cloth. Satin cloth is made of silk using a satin weave.

Satin weaves are used very largely in producing different styles of cotton and silk fabrics, and are also frequently found in woolen goods. They are more extensively used in the manufacture of damask and table-covers than for any other cla.s.s of goods. Satin stripes are frequent in madras, shirtings, and fancy dress goods in connection with plain and figured weaves.

=Figure Weaving.= To produce complicated and irregular patterns in the loom a large number of different openings (sheds) must be made in the warp, and to secure such a large number an attachment is placed on top of the loom called a Jacquard apparatus. The Jacquard is merely an apparatus for automatically selecting warp threads, by which each separate one can be made to move independently of any of the others.

It is provided with weighted strings attached to each of the warp threads. The weighted strings are controlled by wire needles which are in turn controlled by perforated cards. Each motion of the loom changes their position and allows some needles to go through the holes in the cards, thus drawing up the warp, while others strike the card and leave the warp down. In this way the perforations of the cards determine the figure of the patterns. The Jacquard is chiefly used to produce patterns of great width in which all or most of the threads in the pattern move independently. For the weaving of elaborate effects and flowing lines it is practically indispensable. All elaborate designs are cla.s.sed under the name of Jacquards.

=Double Cloth.= Double cloth is a descriptive term applied in weaving to fabrics produced by combining two single cloths into one. Each one of these single cloths is constructed with its own systems of warp and filling, the combination being effected in the loom by interlacing some of the warp or filling threads of one cloth into the other cloth at certain intervals, thus fastening them securely together. The reasons for making double-cloths are many. Sometimes it is done to reduce the cost of heavy weight fabrics by using cheaper materials for the cloth forming the back; again it may be to produce double-face fabric; it allows great freedom for the formation of colored patterns which may or may not correspond in pattern on both sides; it is the basis of tubular weaving such as is practised for making pillow cases, pockets, seamless grain bags, etc.; more frequently, the object is to increase the bulk or strength of certain kinds of fabrics, such as heavy overcoatings, cloakings, pile-fabrics, golf-cloth, rich silk, etc.

=Pile Weave.= A pile weave is a general term under which are cla.s.sed numerous varieties of cloth woven with a pile surface, as plush, velvet, velveteen, and carpeting of various kinds. Turkish towels are an excellent ill.u.s.tration of pile weaving. A pile surface is a closely set, elastic face covering various kinds of woolen, silk, and cotton fabrics, and consists of threads standing close together, either in the form of loops or as erect thread-ends sheared off smooth so as to form a uniform and even surface. In the production of a pile fabric a third thread is introduced into the weaving and formed into loops usually by carrying it over the wires laid across the breadth of the cloth. The wires are afterward drawn out, leaving the loops standing; the loops may then be cut so as to form a cut pile, as in velvet and plush, or they may be left in their original form as in Brussels carpet and Turkish towels.

=Gauze Weaving.= In gauze weaving all the warp threads are not parallel to each other, but are made to intertwist more or less among themselves, thereby favoring the production of light, open fabrics, in which many ornamental lace-like combinations can be obtained. Two sets of warp threads are used, one being the ground warp and the other the "douping," the latter performing the entwining process. Gauze is especially characterized by its openness and yields the lightest and strongest fabric with the least material. When gauze is combined with plain weaving it is styled "leno." Gauze fabrics are designed for women's summer gowns, flounces, window-curtains, etc.

=Lappet Weaving.= Lappet weaving, really a form of embroidery, is used for producing small designs on cloth by means of needles placed in a sliding-frame, the figures being st.i.tched into the warp. Elaborate figures are beyond the range of lappet weaving, but there are many small effects that can be economically produced in this manner, such as the detached spots in dotted swiss, and narrow and continuous figures running more or less into stripes. This form of weaving imitates embroidery and is used mainly on plain and gauze fabrics.

CHAPTER VII

DYEING AND FINISHING

=Dyeing.= When a fabric or fiber is impregnated with a uniform color over its whole surface, it is said to be "simply dyed." On the other hand, if distinct patterns or designs in one or more colors have been impressed upon a fabric, it is called printing.

Vegetable dyes were formerly used, but since the coal tar dyes have been discovered the latter are used entirely. Over fourteen thousand colors have been produced from coal tar. Different fibers and fabrics attract dyestuffs with varying degrees of force. Wool and silk attract better than cotton and linen.

=Wool Dyeing.= The methods of dyeing wool differ considerably from those employed for cotton and other vegetable fibers. They may be divided into three parts: piece dyed, cross dyed, and yarn dyed.

Piece goods are those woven with yarns in their gray or natural state, and then cleansed and dyed in the piece to such colors as are required. They are woven in plain weaves and in a great variety of twills--in fact, in all styles of weaves--and are also made on the Jacquard loom. The princ.i.p.al fabrics in this cla.s.sification are all wool serges, cheviots, hopsackings, suitings, satines, prunellas, whipcords, melroses, Venetian broadcloths, zibelines, rainproof cloths; nun's veiling, canvases, grenadines, albatrosses, crepes, and French flannels; silk warp Henriettas, voiles, and sublimes. Whenever it is possible, it is better to dye textile fabrics in the form of woven pieces than in the yarn. During the process of weaving it is impossible to avoid getting yarn dirty and somewhat greasy, and the scouring necessary to remove this dirt impairs the color used in weaving. Piece dyeing is the cheapest method of applying color to textiles. The chief fault of piece dyeing is the danger of cloud spots, stains, etc., which do not appear in the other two methods.

Then again in the case of thick, closely woven goods the dyestuff does not penetrate into the fabric, and the interior remains nearly white.

The cloth is dyed by means of pa.s.sing over a roller into a dye vat.

Small pieces or "swatches" are taken from the ends of the fabric, and compared with the pattern. For it must be remembered that no two lots of crude dyes are of equal strength, and the wools and cottons of different growths and seasons vary greatly, so that the use of a fixed quant.i.ty of dye to a given amount of goods will not always give the exact shade. In comparing a sample with the pattern the two are placed side by side below the eyes (reflected light), and then held up to the light and the eye directed along the surface. A judgment must be formed quickly, as a prolonged gaze fatigues the eye and renders it unable to perceive fine shades of difference.

[Ill.u.s.tration: DYE ROOM

1. Dye tub or vat containing dyestuffs.

2. Rolls or cylinders upon which cloth is wound.

3. Cloth leaving dye tub--being wound upon No. 2 cylinder.]

=Cross Dyed.= Cross-dyed goods may be described as fabrics woven with black or colored cotton warps and wool or worsted filling and afterwards dyed in the piece. Since cotton has not the same attraction for dyestuffs as wool it is a difficult task to dye a fabric woven with cotton and wool so that both fibers will be identical in depth of color, tone, and brightness. In some cases it is possible to dye a mixed fabric at a single operation, but the usual process is to dye the wool in yarn state and then dye the warp a color as near the color of the wool as possible. In the weaving operation the wool is thrown to the surface. In another method the warp is dyed and woven with a white wool or worsted filling, and dyed in the piece with a dyestuff that will not affect the cotton. In this way the cotton does not take the wool dye, but retains its original color. This cla.s.s of work is generally used in mohair, alpaca, and l.u.s.ter fabrics, because the natural brilliancy of the l.u.s.ter wool, alpaca, or mohair in the filling is not impaired as would be the case if the cotton in the goods were subjected to a cotton-dye bath after being woven. The princ.i.p.al cloths in this cla.s.sification are cotton, warp figured melroses, Florentines, glaces, brilliantines, l.u.s.ters, alpacas, and mohairs; rainproof cloths, and fancy waistings, and in these may be found the same great variety of weaves and patterns that is to be found in the piece-dyed goods already described.

=Yarn Dyed.= Yarn-dyed goods differ from those previously described in that they are made of yarns that are dyed before being woven, or yarns spun from dyed wool. Wool may be dyed in the raw state (fleece), slubbing, or yarn. Fleece dyeing is preferable for goods intended to stand friction, and that in spite of wear and tear must preserve their color. It is preferred for dark colored goods where much friction is to be encountered, but is seldom used for light colors, since these would be soiled during subsequent processes of manufacture. In this case every fiber is colored uniformly all over. The yarn from this wool and the cloth woven from it are dyed through and through and do not become grayish or whitish by wear and tear.

Slubbing dyeing is preferred to yarn dyeing, for the dyestuff penetrates the loosely twisted roving, and if unevenly dyed, the subsequent operations equalize most thoroughly the irregularities in color.

Yarn dyeing is especially applicable to checks, plaids, and suitings, and in their manufacture the drop box loom (a loom with two or more shuttles) is used. Goods manufactured under this cla.s.sification include cotton warp checks and mixtures; all wool homespuns, mixture coatings and suitings, storm skirtings, rainproof cloths. These goods are made in a great variety of weaves, the effect in each being secured by the color and the weave.

Piece-dyed fabrics may be distinguished from yarn-dyed fabrics by unraveling threads of each kind. In the case of yarn-dyed fabrics the dyestuff has penetrated through the yarn, while in the case of piece-dyed fabrics the dyestuff has no chance to penetrate as completely as the yarn-dyed fabric.

=Textile Printing.= Printed fabrics such as print cloths can generally be distinguished by observing the back side of the cloth. If the figure or pattern on the face of the cloth does not penetrate through to the back but only shows the outline, the fabric has been printed.

Fabrics are printed by coming into contact with rotating rollers on which the pattern is engraved.

The attraction of cotton for coloring is generally feebler than that of wool or silk. Few of the natural dyestuffs attach themselves permanently without use of a mordant. A mordant is a substance which has an affinity for, or which can penetrate, the fiber to be colored, and which possesses the power of combining with the dyestuff and thus forming an insoluble compound upon the fiber. Cotton is dyed in an unspun state, and also as yarn or spun thread, either in the hank or skein. Silk is dyed in unspun skeins, although to a considerable extent it is also dyed in the piece.

=Styles.= Since styles and designs are constantly changing it is necessary for the mills to meet this demand by producing new styles.

Some of the patterns which are at this time considered to be in the best style would have appeared much out of date two or three years ago, while perhaps a few years hence, the patterns which are now almost obsolete will, with some changes, become the most popular sellers of the season. As the mill officials or designers are not out among the trade, they are not in a position to judge what lines or patterns would most likely appeal to the market. This information is obtained by the "styler" of the selling house. The styler receives all the latest foreign samples and fashion papers from abroad, and often goes or sends his representative to Europe to ascertain what goods, designs, and colors are taking well over there. The selling agent or styler then supplies the designing department of the mill with all the samples, information, and suggestions necessary in getting out the samples.

=Construction of Cloth.= In reproducing a sample of cloth in the mill it is necessary that the construction of the cloth be first known, that is, there must be ascertained the width, warp ends, and picks per inch, the number or size of the yarn used for the warp, the number that is used for the filling, and the number of ounces per yard or yards per pound. Then the interlacings of the threads in the sample must be picked out in order to get the design or weave on the design paper, from which the data are obtained for regulating the movement of the harness or heddles. Design paper is paper ruled by lines into a number of squares. An imitation of the cloth can be produced on this paper by showing the interlacings of the warp and filling. This is done by filling in certain squares with paint, or pencil marks, while the others are left empty. In practical work it is the general custom to make a cross with a pencil to indicate the squares that are to be filled in, thus showing that the warp thread is over the filling thread at this point. When a square is left blank it shows that the warp thread is under the filling at this point. When a warp thread is up on a certain pick, the harness which controls this thread must be raised on this pick.