Thursday, January 5, 2017

Yarn Consumption Calculation for Woven Fabric

Yarn consumption is measured from woven fabric specification. Yarn consumption means warp weight calculation and weft weight calculation of woven fabric. There are different yarn consumption formula for woven fabric. In this article we will know about woven fabric specification and then calculate weight of fabric.
Yarn Consumption Calculation for Woven Fabric

Woven Fabric Specification:
Woven fabric construction or specification as follows:

                                               EPI X PPI
Fabric specification = ……………………………… X Fabric width
                                    Warp count X Weft count

Or,

                                    Warp count X Weft count
Fabric specification = ………………………………….. X Fabric width
                                              EPI X PPI


For example,

 32 x 40
.................. x 50อดอด
  60 x 54

Fabric Weight Calculation in Running Length:
Calculate the weight of warp and weft yarn in kg to produce 2000m of the following fabric:

150 x 100
------------------ x 58”
50 x 50


For warp weight calculation:

Here, EPI = 150
Total number of ends = 150 x 58

Length of each end = 2000m + 2000m x 0.03                      (warp crimp% = 3%)
= 2060m

Total length of warp yarn = 150 x 58 x 2060 m

We get from the yarn numbering system,

          L x w
Ne = …………….
         W x l

              L x w
=> W = …………………..
             Ne x l

    150 x 58 x 2060 x 0.4536
= ……………………………………… kg + 20% wastage of the total weight of warp
       50 x 840 x 0.9144

From the above system a simple formula is developed to calculate the weight of warp yarn in kg to produce a particular length of a fabric as follows:

Weight of warp yarn in kg =

   EPI x Fabric width in inch x (Fabric length in m + Fabric length in m x crimp%)
= ………………………………………………….......…….........……......………….. x 0.0005905512

                                                           Ne warp

 
                                                                  + Wastage% of total weight of the warp (about 20%)


For Weft weight calculation:

Here, PPI = 100
Total number of picks = 100 x 39.37 x 2000

Length of each pick = (58” + 58” x 0.05) / 39.37             (weft crimp% = 5%)
= 1.547 m

Total length of weft yarn = 100 x 39.37 x 2000 x 1.547m

We get from the yarn numbering system,

           L x w
Ne = …………….
          W x l

              L x w
=> W = …………………..
              Ne x l

    100 x 39.37 x 2000 x 1.547 x 0.4536
= …………………………………………………. kg + 15% wastage of the total weight of weft
              50 x 840 x 0.9144

From the above system a simple formula is developed to calculate also the weight of weft yarn in kg to produce a particular length of a fabric as follows:

Weight of weft yarn in kg =

   PPI x Fabric length in m x (Fabric width in inch + Fabric width in inch x crimp%)
= …………………………………………………......……..………………..…………. x 0.0005905512
                                                   
Ne weft
 
   + Wastage% of total weight of the weft (about 15% although it depends on selvedge, loom type)

Similarly weight of the warp and weft yarn in pound (lb) can be calculated by the following formula:

Weight of warp yarn in Ib. =

    EPI x Fabric width in inch x (Fabric length in yds + Fabric length in yds x crimp%)
= ………………………………………………………..……………………..………………..
                                                  
Ne warp x 840

                                                          + Wastage% of total weight of the warp (about 20%).

Weight of weft yarn in lb =

   PPI x Fabric length in yds x (Fabric width in inch + Fabric width in inch x crimp%)
= …………………………………………………………...………………..……………….
                                                
Ne weft x 840

                                                   + Wastage% of total weight of the weft (about 15%)

Problem:
Calculate the weight of warp and weft yarn in lb to produce 2500yds. of the following fabric:

  120 x 90
…………………. X 58”
   16 x 14

The weight of warp and weft yarn in Ib. can be calculated directly from the fabric specification by using the above formula. It will be very easy and it safe lot of times.

Solution:

Weight of warp yarn in lb =

   EPI x Fabric width in inch x (Fabric length in yds + Fabric length in yds x crimp%)
= ……………………………………………………………………......…..………………..
                                             
Ne warp x 840

                                                                           + Wastage% of total weight of the warp

   120 x 58 x (2500 + 2500 x 0.03)
= …………………………………………………. + 20%
                  16 x 840

= 1333.48 + 1333.48 x 0.2
= 1333.48 + 266.696
= 1600.176lbs Or 725.84 kg (1600.176 x 0.4536)


Weight of weft yarn in lb =

   PPI x Fabric length in yds x (Fabric width in inch + Fabric width in inch x crimp%)
= …………………………………………………………………….....…………..…….
                                           
Ne weft x 840

                                                                  + Wastage% of total weight of the weft (about 15%)

   90 x 2500 x (58 + 58 x 0.05)
= ………………………………………. + 15%
               14 x 840

= 1165.18 + 1165.18 x 0.15
= 1339.96 lbs Or 607.804 kg (1339.96 x 0.4536)