পৃষ্ঠাসমূহ

বৃহস্পতিবার, ১৭ মে, ২০১২

production planning of fabric


                                                      Production planning of woven Fabric

           Introduction:
                                  Production Planning
ü  Taking order form marketing division
ü  Analyzing the orders
ü  Planning for dyeing the yarn
ü  Planning for weaving the fabric
ü  Planning for finishing the fabric
Literature Survey:
                                               Production Planning
            
Sample Taking
Sample construction
(Count, EPI, PPI)
Weaving Construction
(Fabric Design and Analysis)
Yarn consumption
Weaving

Flow chart of Weaving
Winding:
This is a process of transfer of yarns from ring, bobbin, hanks etc, into a convenient from of package containing considerably long length of yarn. This simple transfer of yarn from one package (bobbin) to another large package (cone, spool, pirn) is called winding.
Objects of winding:
ü  To improve the quality of yarn
ü  To get a suitable package
ü  Make continuous supply of yarn in the subsequent process
ü  Removal of thick &thin place from the yarn
ü  Removal of weak places from the  yarn
ü  Removal of slubs
ü  Removal of knots
ü  To store the yarn

Sequence of winding:

Yarn in ring bobbin
Guide
Tension
Yarn clearer device
Stopping device
Traversing guide
Winding

Defects of winding:
ü  Formation of patches on the yarn.
ü  Incorrect winding speed.
ü  Tension variation.
ü  Dirty package.
ü  Incorrect shape of the package.
ü  Piecing up.
ü  Too much knots in the yarn.
ü  Greasy & dirty yarn.
ü  Excessive full bobbin.

Warping:
The parallel winding of yarn from cone or cheese packages on to a warp beam is called warping. Warping is a process of transferring yarn from a predetermined number of single-end packages, such as cones or cheeses, into a sheet of parallel yarns of a specified length and width.
Objects of warping:
ü  To wound up fixed (required) length of yarn on to a warp beam.
ü  To increase the weavability of yarn.
ü  To make dynamic next process.
ü  To increase production.
ü  To increase quality of fabric.
ü  To make re-useable small packages.
ü  To make convenient yarn sheet for sizing process.

Yarn passing diagram

Sizing: The weaving process requires the warp yarn to be strong, smooth and elastic or extensible to a certain degree.  To achieve these properties on the warp yarns,  a protective coating of a polymeric film forming agent ( size ) is applied to the warp yarns prior to weaving. This is called sizing or slashing.
Types of Sizing
1) Conventional aqueous sizing
                (a) Double cylinder sizing     
                (b) Multi cylinder sizing
2) Non conventional sizing
                (a) Dry sizing
                (b) Solvent sizing
                (c) Hot melt sizing
                (d) Foam sizing
Main Purposes of Warp Sizing:
ü  To increase the strength of the yarns
ü   To reduce the yarn hairiness
ü  To increase the abrasion resistance of the yarn against other yarns
ü  To reduce fluff and fly during the weaving machine process for high speed weaving machines.

Before sizing & after sizing Yarn:


Appearance of size spun yarn:

Weaving:
Weaving is the interlacing of two or more threads or pieces of material in order to create a joined structure. Weaving is the process of making cloth, rugs, blankets, and other products by crossing two sets of threads over and under each other. Weavers use threads to spun from natural fibers like cotton, silk, and wool synthetic fibers such as nylon.

Process Flow Chart of Weaving:
Warp Wise Yarn Path
Weavers beam
Back rest roller
Feeler roller
Warp stop motion or drop wire
Heald Eye
Reed
Take Up Roller

Weft Wise Yarn Path
Bobbin Creel
Pre Winder
Programmable Filling Tensioned (P F T)
Fixed Nozzle
Movable Nozzle
Filling Cutter
Relay Nozzle
Filling Detector
Stress Nozzle
Waste Cutter
Case Study: Some use full formula for production planning
Pre calculation:
Total fabric production=
       Total length+ Excess amount of fabric in %
•Total end=EPI × Width of the fabric
• Reed count = EPI- Crimp%
Reed space = Total ends ÷ Reed count

          Yarn Consumption: Warp yarn= [{ Total ends ÷ (warp count ×  840) + waste% }]
          Weft yarn = [{ PPI × (reed space + waste)} ÷ weft count × 840]

Warping:
          NO. Of cone = Total End ÷ NO. of warp beam
          Cone length =(cone wt. in lbs × count × 840) yds
          Set length = cone length ÷ No. of warp beam

          Weaver’s beam: Length of weaver’s beam = length of warp beam + sizing extension

Crimp% calculation:
          For 40’s yarn:
Sizing beam length = 1800 yds
Waste in head of the beam = 4 yds
Waste in tail of the beam =   9 yds
Total waste of yarn from beam after sizing = (4+ 9) yds
                                                                                         = 13 yds
Actual beam length = (1800 – 13) yds
                                      = 1787 yds
1787 yds sized yarn produce 1590 yds fabric
Less amount of fabric produce due to crimp = (1787 – 1590) yds
                                                                                         = 197 yds
Due to crimp 1787 yds reduce = 197 yds
Due to crimp 1 yds reduce      = 197 ÷ 1787 yds
Due to crimp 100 yds reduce = (197 X 100) ÷ 1787
                                                                = 11.02 %
Actual crimp% for 40’s yarn = 11.02
Above all, we can say that we learned this type of topics Production Planning
          Flow chart of Weaving
          Winding
          Warping
          Sizing
          Weaving
          Calculation formula
          Crimp% calculation

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