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Knitted fabrics and their properties

31 de Jan de 2017
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Knitted fabrics and their properties

  1. Chapter 9 Knitted Fabrics and Their Properties Knit fragments dating back to 250 BC ◦ Compared to 9,000 years for wovens Introduced to Europe by the Arabs ◦ Did not gain popularity until around 1,000 AD
  2. Knitting The act of interlooping yarn to create fabric as opposed to weaving, which is interlacing yarns to create fabric. Loop Components Loop Appearance
  3. Knitting Industry Two main segments ◦ Knitted yard goods ◦ Knitted apparel Advances in computer technology ◦ Ability to respond quickly to the rapidly changing fashion industry
  4. Knitting Machines Two basic types of knitting machines ◦ Flat knitting machines – Fig. 9-2 p. 140 Produce flat fabric Produce both warp and weft knits
  5. Knitting Machines ◦ Circular knitting machines – Fig. 9-3 Predominately weft knits Produce tubular fabric Faster than flat knitting machines
  6. Knitting Machines Seamless knitting machine ◦ Seamless garment is made from a very special state of art tube knitting machine
  7. Categories of Knits Two main categories ◦ Weft knits (on left) Sometimes called filling knits ◦ Warp knits (on right)
  8. Knit v.Woven Major difference between knitted and woven fabrics ◦ Knitted fabrics – interlooping yarns to create fabric ◦ Woven fabrics – interlacing yarns to create fabric
  9. Knit vs.Woven
  10. Knit v.Woven KNITS (slide 1) ◦ Cheaper to produce ◦ Require higher quality yarns ◦ Yarns must be uniform so that thin spots don’t form on the fabric ◦ Looped structure = Knit fabric is less opaque provides less cover Allows for stretch + recovery as body moves Requires thicker and/or heavier yarn to provide equal cover to that of a woven Tendency to snag /run in weft knits
  11. Knit v.Woven KNITS (slide 2) ◦ Easier / quicker to change design patterns ◦ Known for comfort and ease of fit ◦ Bulky = good insulation and warmer ◦ Wrinkle recovery superior ◦ Problem with stretching out Should be folded not hung Sagging at stress points (knees, elbows) ◦ Shrink more than wovens
  12. Knit v.Woven WOVEN ◦ More expensive to produce ◦ Can use lower-quality yarns ◦ More difficult to change pattern on loom ◦ Looms use more energy/louder than knitting machines ◦ More rigid/less able to conform to body ◦ Superior resistance to wind ◦ Can be set with sharper pleats and creases ◦ Do not stretch out/can be hung ◦ Less tendency to hang ◦ Less tendency to shrink than knits
  13. Knitting Terminology Stitch ◦ The loop of yarn formed by the knitting process Knit ◦ Basic knitting stitch Purl ◦ Horizontal rows Wales ◦ Loops formVertical ribs/columns – parallel to selvage Gage or Gauge ◦ the density of knitting machine needles, and the number of knitting needles per inch (approx. 2.54cm). The smaller the figure, the coarser the stitch, and vice versa
  14. Gauge example
  15. Knitting Terminology Courses ◦ A series of successive loops laying crosswise in the fabric Face/Back ◦ Just like a woven fabric, there is a face and a back to the knitted fabric Cut ◦ The fineness of weft knits made on a circular knitting machine The higher the gauge or cut number, the finer the fabric
  16. Components of Knit Construction
  17. Variables in Knitted Construction A great deal of variety may be created by manipulating the following: ◦ Fiber content ◦ Yarn type and twist ◦ Fabric count ◦ Coloration ◦ Finishes
  18. 4 stitches make us all knit fabrics
  19. Weft Knits ◦ Can be made by hand knitting, or a circular or flat bed machine ◦ Made with one continuous yarn that travels around the fabric on a circular knitting machine and across the fabric on a flatbed machine. ◦ Common weft knits: jersey knits rib knits, purl knits Wales on front – vertical Courses on back - horizontal
  20. Weft knit–vertical wales on face
  21. Weft knit–horizontal courses on back
  22. Weft Knit StitchVariations Miss or Float Stitch ◦ Used to create patterns or change colors ◦ Reduce the stretch of the fabric ◦ Prone to snagging Tuck Stitch ◦ Used to create pattern and textured effects ◦ Identified by open lacy areas, bubbles, puckers ◦ Reduce the stretch of the fabric Open,Transfer or Spread Stitch ◦ Fashion marks Shaped to fit during the knitting process
  23. Weft Knit StitchVariations Open,Transfer or Spread Stitch ◦ Create texture ◦ Fashion marks Occur when transfer stitches change the number and position of the yarns Shaped to fit during the knitting process ◦ Mock-fashion marks Do not shape the garment
  24. Float stitch knit–face
  25. Float stitch knit–back
  26. Tuck stitch knit–face
  27. Tuck stitch knit–back
  28. Full-fashion marks
  29. Mock full-fashion marks
  30. CommonWeft Knits Jersey knits ◦ Also called single knits ◦ Economical to produce ◦ Knit stitches on front/ Purl stitches on back Rib knits ◦ Knit and purl wales alternate across width Purl knits ◦ Alternate courses of knit and purl stitches on both sides of the fabric
  31. Characteristics of Jersey Knits Stretch crosswise and lengthwise ◦ Stretches more in the crosswise Tend to run or ladder if stitch breaks Produced under tension ◦ Fabric less stable and curls when cut Special finishes ◦ Counteract curling and improve stability
  32. End Uses of Jersey Knits Sheets Sweaters T-shirts Men’s underwear Dresses Hosiery
  33. Jersey KnitVariations (pg 142-143) Fleece #101 Intarsia Jacquard knits #97 Knitted terry #102 Knitted velour #111 Lisle Plaited knits Silver-pile knits
  34. Characteristics of Rib Knits Swatch #100 Reversible More elastic than jersey knits More stretch crosswise than lengthwise Edges do not curl Running and laddering still a problem More expensive to produce
  35. Rib Knit Diagram
  36. End Uses of Rib Knits Collars Necklines Cuffs Bottom edges of sweaters Knit hats Men’s hosiery
  37. Rib Knit Diagram
  38. 2x2 rib knit–face or back
  39. 1x1 rib knit–face or back
  40. Rib KnitVariations Double knits #104 & #105 ◦ Sometimes called double jerseys ◦ Thicker than jersey knits ◦ Two-way stretch ◦ Very stable – will not ladder ◦ Apparel and Upholstery used Interlock knits #103 ◦ Specialized 1x1 rib knit ◦ More stable and smoother than regular rib knits ◦ Will ladder ◦ Underwear, blouses and dresses
  41. Interlock Diagram
  42. Purl Knits Produced on links and links machines ◦ Slowest of the knitting machines ◦ More expensive Good stretch in all direction ◦ Stretches out of shape easily Crosswise stretch less than a jersey knit Thicker than jersey knits Does not curl
  43. Purl knit–face or back
  44. End Uses for Purl Knits Infant and children’s wear Sweaters Scarves
  45. Warp Knits – see Fig. 9-8 Second major category of knit fabrics Characterized by vertical loops More resistant to laddering than weft knits Usually done on flat knitting machine ◦ Two main types of warp knitting machine (name = machine and fabric name) Tricot #106 Raschel #107 Minor warp knit – Simplex
  46. Characteristics of Tricot Knits Good elasticity Best of warp knits Inexpensive and quick to produce Curls along crosswise edge Good air and water permeability Soft Crease resistant Good drapeability
  47. End Uses for Tricot Knits Lingerie Nightwear Blouses Dresses Used as a backing fabric in multi- component structures Limited interior uses because of high elongation
  48. Tricot KnitVariations Brushed tricot Satin tricot Tricot-net fabrics Tricot upholstery Tulle
  49. Raschel Knits Swatch #107 Similar to Tricot Knits Greater diversity in design Differences between Raschel and Tricot Knits ◦ Raschel has: More texture Open spaces Made from heavier yarns
  50. Diagram of Simple Raschel Crochet Knit
  51. Variations and End Uses of Raschel Knits Warp knitted Fine laces and nets Heavy carpets Thermal underwear with a waffle effect Power-net fabrics for swimsuits and foundations Heavy blankets May resemble hand crocheted fabrics
  52. Weft Insertion Knits Insertion warp knits: ◦ Extra yarns may be inserted in the warp or in the filling direction of warp yarns InlayYarns: ◦ If yarns are inserted in warp direction Power-net fabric: ◦ Raschel knit with inlaid spandex yarns.
  53. Weft Insertion Characteristics Fabric Appearance ◦ Extra set of yarns laid in ◦ Typically novelty yarns ◦ Other yarns may be laid in to add strength or stretch Help add warmth or strength Can be single or double knit May also be warp knit
  54. Diagram of Knitted Net
  55. Care and Performance Dimensional Stability = poor ◦ Stretch contributes to comfort but also to poor dimensional stability ◦ Prone to shrinkage, stretching, and distortion ◦ Finishes Shrinkage control Heat setting of synthetics Resin finishes Air drying and dry cleaning and help minimize shrinkage Pilling
  56. Care and Performance Pilling ◦ Made from fibers and yarns that are likely to pill – wool and synthetic fibers Snagging ◦ Looped structure of knit fabric increases the possibility that snags occur If yarn has not been broken it is possible to work back into the fabric
  57. Handling in garment construction Pattern ◦ Seam allowances vary on patterns, the 1/4" (6 mm) seam allowance is the easiest to use. Layout ◦ Knits have shading and pattern pieces should be cut in one direction and be placed with the greatest degree of stretch around the body. Marking and Cutting ◦ Use weights to hold pattern pieces in place.A rotary cutter works very well with knits, just be sure to use a matt to protect your cutting table.
  58. Handling in garment construction Lining ◦ Interfacing is used to reinforce closures, add shaping to collars, cuffs and plackets and stabilize areas such as shoulder seams and some necklines.The best interfacing is a 100% polyester fusible lightweight knit interfacing. Stitching ◦ Sew the seam using an overlock stitch.This stitch sews and overcast in one step. It is not necessary to stretch the fabric while sewing as stretch is built in. Fasteners
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