Fall 2013 Exam 3 Study Guide Chapter 18 Knits Know knitting terminology Stitch each loop in a knit fabric Course left to right rows of loops across the width of the fabric Wale up and down columns of loops Gauge number of stitches per inch across the width of the fabric usually expressed in a fraction the higher the gauge the closer the stitches Stitch density by the wales number of stitches or loops per square inch To find multiply the courses Know the difference between weft knitting and warp knitting Be able to recognize diagrams of both Weft knits are knits in which the yarns interlace in a horizontal directions Warp knits have yarns that interlace in a vertical direction Weft Knits Warp Knits knit purl A knit can also be jersey plain stitch Know two basic weft knitting stitched knit and purl and how they can be combined The two basic aft knitting stitches are All of the loops look the same and are meshed in the same manner the wales show on the fabric face and courses show on the fabric back A purl knit has the filling loops go behind the loop above it When the two are combined they make rid knits The lengthwise rids are formed by wales alternating on the face and back of fab ric or alternating knit and purl stitches Know knitted fabrics structures Jersey Also called plain or knit stitch all of the loops look the same and as meshing in the same manner Wales show on the fabric face and courses show on the fabric back It is the most easily distorted of all knits and the edges curl There is more stretch in the crosswise than the lengthwise direction It fits the body closely and is often used with technical back as the right side of the fabric Purl Filling knit loops go behind the loop above it There is a high crosswise and lengthwise stretch Small quantities of fabric made in purl knit Rib Lengthwise ribs formed by wales alternating on face and back of fabric Made by alternating knit and purl stitches Greater elasticity in the width than the length Staple does not curl Jacquard The design is woven in rather than printed on the surface Historically most ingenious design Many are large designs They are made on special Jacquard looms Combine twill plain and satin weaves often in the same row The must contain at least two of the basic weaves Missed Stitch In order to create a design effect a stitch may be missed in a regular pattern Know how fake fur and pile knits are made They are called sliver knit piles A sliver is a continuous strand of loosely assembled fibers that is fairly uniform and without twist The loose fiber from sliver is knitted into the back Know the two types of warp knit tricot raschel What types of fabric they make Tricot is made with two sets of threads and fine vertical wales on the face Yarns zigzag down the length of the fabric back There are crosswise ribs on the back of the fabric like chevrons on their sides because of the zigzag pattern of the yarns Tricots usually make swimwear and lingerie because it is lightweight Raschel can be any weight of thickness and can range from lace to carpet The common feature of raschel is the pillar and inlay effect Columns of loops are connected by in laid yarns traversing from column to column up the fabric NONWOVENS Know how the fibers for nonwovens are put in position Dry forming or Wet forming Carded webs are mad in a manner similar to the process for slivers for yarn spinning except that the thin film of fibers removed from the card is not drawn together into a sliver but is laid onto a conveyor Know examples of the means for bonding consolidating the fibers Mechanical Needlepunching spun lacing and stitch bonding are examples of mechanical bonding EX 10 in your manual true felt is mechanically bonded Thermal This method is used for carpet backing apparel interlinings and geotextiles Also called heat setting the use of thermoplastic fibers when at a certain temperature melt and bond to each other as they cool The fibers are strong and not easily torn EX 8 20 in your manual Spunbonding filaments are blown onto a moving belt where they form a web As the still hot and partially molten filaments touch they bond Chemical Applying an adhesive material to the web and then setting the adhesive This glues the fibers together EX 32 57 Solvent softens fiber for chemical bonding Stitch fibers are laid out and held together by stitching This is often done with warp knitting on the back EX 45 Know some durable and non durable uses for nonwovens Durable Geotextiles Interfacing Insulated clothing Imitation fur Upholstery backing Wall covering backing Non Durable Throw away after one use Diapers Teabags Examination gloves Wipes Dental bibs Know that felt was the earliest non woven made mechanically bonded Chapter 20 Other Fabric Construction Methods Know the basic compound or multicomponent fabrics and how they are made Tufted fabrics A fabric that has a pile consisting of tufts or loops formed by inserting yearn into a previously prepared backing fabric Embroidery Two components fabric base and yarn that decorates it Quilted Fabrics Composed of three parts Filling material batting and two layers of deco rative out fabric They provide good thermal insulation because inner layer traps air Filler layer today is usually made from polyester They can be made by quilting stitches either hand or machine made bonding with adhesive or ultrasonic method using sound waves to generate heat Laminated Bonded Face fabric joined to a continuous sheet material in such a way that identity of SM is retained may or may not be joined on back with another fabric Flocked Fabrics Short fibers are adhered to surface of fabric to give illusion of pile fabric Adhesive used on base fabric flock is applied mechanical led or electostatically Coated Fabrics Babrics coated with thin polymer films polyvinyl chloride polyurethane Provide protection water chemicals weather Simulate leather or other materials Ultrasuede Multicomponent non woven composed of polyester mircofibers non woven wed is mechanically bonede by needle punching or by hydroentangling Impregnanted with polyurethane Surface brushed to create suede like texture Stitch bonded fabrics Fiber webs are stitches through to hold the fibers together One component is a fiber web yarns of preformed fabric The other is a series of stitches that hold it together Warp and filling yarns laid loosely one over the other Third set of yarn stitches the warp and weft yarns together This is less expensive than weaving