Knitting with Roica Spandex Farna Textiles Pvt Ltd Pakistan'

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Knitting with Roica SpandexFarna Textiles (Pvt)
Ltd Pakistan.
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Basics of Knitting
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Knitting

• Method of making fabric by making loops of
  yarns
• Knitted Fabric is
• Flexible
• Stretchable
• Comfortable
• Casual

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Types of Weft Knitting

• Circular Knitting
• Most Body fabrics
• Single Needle Bed
• Jersey, Jacquard, Pile, Inlay
• Double Needle Bed
• Rib, Interlock, Jacquard
• Double Cylinder
• Purl

• Flat Knitting
• Collars, Trims etc.
• Single Needle Bed
• Domestic
• Double Needle Bed
• V-Bed, Flat Purl, Collars, Trims

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Basic Knitting Action
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Types of Stitches (Loops)

• KNIT Stitch
• Needed to hold the fabric together
• Stabilizes the fabric
• TUCK Stitch
• Used to create a hole in the fabric structure
• Increases widthwise stretch-ability of the
  fabric, reduces it length-wise
• MISS Stitch
• Used to hide a yarn from the face of the fabric
• Reduces widthwise stretch-ability of the fabric,
  increases length-wise stretch-ability

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Stitch Density

• Total number of knitted loops in a given area
• Unit stitches/cm2
• Lower the stitch density,
• more open the fabric is.

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Stitch Length

• The length of yarn used to make one knitted
  loop
• Unit mm
• Larger the stitch length, more open the fabric
  structure is.

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Area Density (GSM)

• Weight of unit area of fabric
• Unit
• GSM (grams /square meter)
• Oz/yd2

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Gauge

• No. of needles per cm on knitting machine
• You can find out the suitable tex for a given
  gauge by using this formula

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Knitted Fabric Shrinkage

• Shrinkage Stages
• On Machine STRAINED
• Off Machine DRY RELAXED
• Static Soak WET RELAXED
• Agitated Soak FINISHED RELAXED
• Tumble Dry FULLY RELAXED

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Spirality Drop

• Spirality (Twisting)
• Angle of wale to vertical.
• Fabric twists when taken off the machine (Dry
  Relaxation)
• Drop
• The angle of courses to horizontal.
• Because of high number of yarn feeders.

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Introduction of Roica Spandex in Weft Knitted
Fabrics
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Plating at the Needle

• ? ROICA
• ?
• Companion Yarn

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Knitting with Roica

• Normally yarn tension can be set close to 10 of
  denier used e.g 40 den use 3-4g or CN.
• Use sensitive tension meter to gauge Roica
  spandex tension, adjusting tension with hand feel
  etc doesnt give good idea of tension and
  eventually in case of too low tension lot of
  spandex goes into the fabric that is how money is
  lost. Use advantage of using high quality spandex
  like ROICA.
• Its important in knitting Hall there is one
  tension meter with 1-10 CN and check tension
  regularly to have good control from machine to
  machine.
• Have weft stop motions in good condition, so as
  parts of machines, specially align clean those
  parts through which Roica is plaited. keep them
  in good state and clean them regularly.

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Heat setting Roica containing fabrics

• What does it mean?
• Relieving tension of Roica reducing the denier
  and fusing the bare yarn. Improve elastic
  properties
• In CK fabrics
• - relieving the tension of Roica
• - reducing the retroactive force
• - lowering the denier
• - reduces the power
• - producing a wider, lighter fabric with less
  stretch
• How does heat setting take place?
• - wet/steam conditions above 120C
• - dry heat above 180C

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Bad Chemicals Conditions

• Use of unsaturated chemicals (oils, lubricants,
  sizes)
• Use of heavy metal catalysts (e.g. MgCl2)
• High pressure steaming (gt10 P.s.I.g.-240 F) 115C
• High pressure dyeing (gt230 F-7 p.s.I.g.)110C
• Excessive heat exposure (e.g., 430 F 90 seconds
  or longer) 220C
• Exposure to Chlorine (e.g., bleaches containing
  chlorine)
• Use of Phenolic carrier
• Prolong exposure to U.V. radiation

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Cotton fabrics with Roica

• Processing steps
• Heat setting
• Roica under tension, temp 180-190C, 40 - 45
  s (Pls use 10-20C lower temperature for BX type
  Roica)
• Slitting
• Removes water and slits fabric in one
  operations
• Dyeing/bleaching
• Roica suffers no ill effects from exposure to
  dyes
• mercerization used to improve dyeability
• bleaching agents hydrogen peroxide

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Presetting and post setting sequence

• Presetting sequence
• steam relax ? slit ? heat set ? scouring dye ?
  dry
• Post setting sequence
• steam relax ? scouring ? dyeing ? slit ? heat set
  ? dry
• more difficult method. Centre crease and rope
  marks formation