Spring 2014, Exam 3 Woven fabricsAll notes on woven fabrics even though we covered some on Exam 2. KNITS- knitted fabrics are formed by interlocking loops of yarns. The interlocking of these loops can be done by either vertical or horizontal movement. When the yarns are introduced in a crosswire direction, at right angles to the direction of growth of the fabric-The knits that run across the knit is known as a weft knit (or a filling knit)-The knits the run up and down (lengthwise) are known as a warp knit Course- crosswise rows of stitches or loops. Wale-the rows of stitches that run in columns along the lengthwise direction. This corresponds to the warp direction of woven fabric. Gauge- used to describe the closeness of knit stitches. The number of needles in a measured space on the knitting machine. Higher gauge fabrics (those with more stitches) are made with finer needles; lower gauge fabrics are made with coarser or larger needles. Cut- used to designate the number of needles per inch in the needlebed of a circular weft-knitting machine. EX- eighteen cut fabric. -The quality of needles used in manufacturing knit goods is related directly to the quality of the fabric produced. Needles of uneven size and quality will produce knit fabrics with uneven-sized stitches and imperfect surface appearance. Stitch densityKnow the difference between weft knitting and warp knitting. Be able to recognize diagrams of both.Weft knitting- a knitted fabric in which the loops interlace horizontallyWarp Knitting- a knitted fabric in which the loops interlace vertically Know two basic weft knitting stitched (knit and purl) and how they can be combinedKnow knitted fabrics structures:Jersey-machines with one needlebed and one set of needles are called jersey machines orsingle-knit machines. With one set of needles and one needlebed, al needles face the same direction; all stitches are pulled to the same side of the fabric. As a result, jersey fabrics have a smooth face with wales prominent on the fabric face and courses prominent on the ack side.. Theloops formed are formed in one direction only which gives a different appearance to each side of the fabric. Stretches slightly more in the crosswire than the lengthwise direction. If one stitch breaks then the fabric may run. Tend to curl at the edges and are less stable than are some other types of knits bc of the extra pressure when knitting. -made for things such as T-shirts, hosiery, sweaters, other wearing apparel.-can also be made into designs of two or more colors by use of a patterning mechanism that controls the selection and feeding of yarns and types of stitches to create jacquard knits. -can also be made in the form of knitted terry farics and knitted velours. Two yarns are fed into the machine simultaneously, picked up by the same needle, and knitted in such a way that one of the yarns appears on the face of the fabric, the other on the back.Purl- purl machines have two needlebeds and one set of needles. Because the machine moves only to the lefts it is also called a links links machine. The simplest purl fabric is made by alternating courses so every other course is drawn to the opposite side of the fabric, thereby producing a fabric with the same appearance on bth sides. Raised courses produce a somewhat uneven texture. Have high stretch in both directions. Often used for sweaters. RibJacquard- sculpted or raised surface effects and elaborate patterns. The jacquard loom controls each warp yarn separately by threading it through a loop in the end of a leash or cord. Before the loom is set up, a design is worked out on graph paper or on a computer, and the position of each of the yarns in the design is analyzed. Missed Stitch- some needles are immobilized and instead of catching the stitch, they allow the yarn to be carried across the back of the fabric. The float stitch can be used to hide colored yarns at the back of the fabric when they do not appear in the design on the face. When long straight flats are used, the elasticity of the fabric is reduced, and long floats are likely to be caught or snagged in use. Know how fake fur and pile knits are made-usually knitted by a jersey machine. While the knitting is taking place, a sliver of staple fiber is fed into the machine. These fibers are caught in the tight knit ad are held firmly in place. Although any staple fiber can be used for the pile, the greatest quantities of these fabrics are made with acrylic and modacrylic fibers in the pile. Byusing staple fibers of varying lengths, adding color through fiber dying or printing on the surface of the pile, and shearing or brushing th pile, an enormous variety of effects can be achieved. Know the two types of warp knit—Tricot- tricot machines account for the largest quantity of warp knits. Tricot fabric is knit flat. On the face side, the wales create the appearance of a fine, lengthwise line. On the back side, crosswise ribs appear in a horizontal position. Relatively unstable and rarely used for garments. It is used for backing for some bonded fabrics. Raschel—can range from finely knitted laces to heavy-duty fabrics. Elaborately patterned surface effects can also be achieved with the raschel machine. The fabrics have lengthwise rows of loops held together by laid-in yarns and may, to the eye, have the appearance of woven goods or lace. Can be used to mimic embroidery or in others woven or lace. NONWOVENS- sometimes called fiber webs, are textile structures “produced by bonding or interlocking of fibers, or both, accomplished by mechanical, chemical, thermal or solvent means and combinations thereof”. This excludes fabrics that have been woven, knitted, or produced by other means. - Skip the yarn stage and go directly from fiber to fabric= nonwoven. Technically paper is a nonwoven. More examples include a mask that doctors use over their mouth, diapers. Bonding isusually done by glue or adhesive can be done mechanically or thermally. Go directly from fiber to fabric and skip the yarn stage. The nonwoven industry is worth about $60 billion, most of it in disposables and semi durables- according to the nonwoven lab at Texas tech university. Most of the disposables are not covered by the care labeling rule because you don’t clean them, you use them once and then throw them away. There are a few companies that are experimenting with making nonwoven fabrics that can be reused. Nonwoven fabrics made directly from fibers bypassing