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Change of fabric GSM vary with yarn count.

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GENERAL INTRODUCTION • Fabric is a manufactured assembly of fibres and yarns that has substantial surface

area in relation to its thickness and sufficient cohesion to give the assembly useful mechanical strength. Fabrics are most commonly woven or knitted but the term includes assemblies produced by felting, lace making, net making, non woven processes and tufting. Our project basically is on knitted fabric specification and machines which are related to knitted fabric production.

• The title of our project work is Analysis of knitted fabric specification and other related machine specification. There are problem in our industries to produce knitted fabrics of required G.S.M. Other specification like fabric width, fabric thickness is generally maintained in industries by previous data sheet. For this reason there are problem if any order comes which didn’t produced in previous.

• Our target is to find out the easy process to get decision about yarn count selection, loop length selection, machine Diameter selection & machine gauge selection.  

• We strongly think that by this process we can get decision about yarn count, loop length, machine gauge, and machine diameter for the single jersey, Rib and interlock fabric.

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Aim of the project work

Find out relation between yarn count and GSM.

Find out the logic of selection of stitch length selection.

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LITERATURE REVIEW • What is yarn

Yarn is a long continuous length of interlocked fibers, suitable for use in the production of textiles, sewing, crocheting, knitting, weaving, embroidery and rope making.

• What is FabricFabric or cloth is a flexible artificial material that is made by a network of natural or artificial fibers. The example is thread or yarn which is formed by weaving or knitting as in textiles. Cloth is mostly used in the manufacturing of clothing and household furnishings etc.

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WeavingWeaving is a method of fabric production in which two distinct sets of yarns or threads are interlaced at right angles to form a fabric or cloth. The longitudinal threads are called the warp and the lateral threads are the weft or filling. The method in which these threads are inter woven affects the characteristics of the cloth.

Fig. Interlacement of warp & weft

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Knitting

Knitting is a method by which thread or yarn may be turned into cloth or other fine crafts. Knitted fabric consists of consecutive rows of loops, called stitches. As each row progresses, a new loop is pulled through an existing loop. The active stitches are held on a needle until another loop can be passed through them. This process eventually results in a final product.

Fig. Looping diagram

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Course: A course is predominantly horizontal row of needle loops produced y adjacent needles during the same knitting cycle.

Wales: A wale is a predominantly vertical column of intermeshed needle loops produced by the same needle knitting at successive knitting cycle. A wale commences as soon as an empty needle starts to knit.

Stitch length: Is theoretically a single length of yarn which includes one needle loop and adjacent needle loops on either side of it

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GSM = Grams per Square Meter. A measurement system more commonly seen in paper, but also seen in t-shirts, it measures the weight of the sheet (of fabric, paper, etc.), which will give you some indication of its thickness. There are two formulas for calculating the GSM of knitted fabric:-

GSM =

• Course per inch x Stitch length x 39.37 x 39.37 x

Tex=

1000 x 1000

GSM =

WPI x CPI x SL (mm) x 0.9155=

Count (Ne)

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SOME MEASUREMENT NEED FOR GSM CALCULATION

CALCULATION OF WALES PER INCH: We calculated the number of wales in 10 inch fabric unraveling the

yarn. Then we divide the no. of total wales by 10 inch to getting the wales per inch.

CALCULATION OF COURSE PER INCH: We calculated the number of course in five inch with the help of counting glass and needle. Then we divide the total no. of course by five inch to getting the course per inch.

MEASUREMENT OF STITCH LENGTH: In order to determine the stitch length, we count 100 no wales or stitch and count its length by hanging the yarn on the stitch counter. The reading is found in mm unit.

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MEASUREMENT OF YARN COUNT: We have fallowed a different way to find out the count of the yarn. At first we unravel a considerable no yarn from the fabric. Then we measured the total length of the yarn and measured the weight of that no of yarn. From these weights, we find out the count of the yarn. The equation we followed is as follow:-

n-1 x 453.6 Count = Wt x 36 x 840 Where, n= number of yarn in bundle.

L= length of yarn. Wt= weight of yarn.

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Yarn count is calculated in two systems: a. Direct system b. Indirect system

• Direct system: In this system the the weight per unit length is the yarn count. This is use for thrown silk, artificial silk, jute etc and count calculation formula is the following

W x lCount = LHere, W = weight of sample.

L = length of sample. l = unit length in system.

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Indirect system: In this system the count of yarn express the no of unit length per unit weight. In this system higher the yarn count finer the yarn. It is generally used for cotton, worsted, woolen, linen etc and the yarn count calculation formula is the following:

L x wCount=

W x lHere, W = weight of sample.

L = length of sample. w = unit weight in system. l = unit length in system.

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GSM DEPENDS ONThe main material for knitting process is yarn. The quality of knitted yarn should be like as follows:

Parameter 30/1 Cotton Combed 30/1 Cotton Carded 30/1 Poly Cotton

Best Acceptable

limit

Best Acceptable

limit

Best Acceptable

limit

Uniformity % 9 – 9.5 9.7 – 10.2 11.5-12.1 12.8-13.5 9.5-9.8 10.4-10.7

Thin (-50%) 0 3 - 5 16-22 50-60 2-3 7-10

Thick (+50%) 7 - 12 32-43 75-90 250-300 15-20 34-42

Neps (+200%) 38 - 47 73 - 88 140-175 300-380 30-45 48-58

Hairiness 4.0 – 4.4 4.6 - 4.9 4.75-5.1 5.5-5.8 4-4.44 4.45-4.8

Tenacity (CN/tex)

21.8 – 22.6 18.4 - 18.9 16.7-17.6 16.2-15.4 25.5-24 23.4-22.1

Elongation 6.7 – 6.9 6.2 - 6.4 7.3-7.08 6.6-6.4 14.7-13.7 11.8-11.214

YARN COUNTThe following counts of yarn that are widely used for knitting

process are given: • a) Cotton: 20/1, 24/1, 26/1, 28/1, 30/1, 34/1, 40/1 Ne. • b) Terylene cotton: 20/1, 24/1, 26/1, 28/1, 30/1 Ne. • c) CVC: 26/1, 28/1, 30/1, 34/1 Ne. • d) Melange: 20/1, 22/1, 26/1, 30/1 Ne. • e) Spandex: 40D, 70D. • f) Polyester: 75D, 150D. • g) Sewing thread: 40/2, 150D etc.

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RELATIONSHIP BETWEEN KNITTING PARAMETERS

1. Stitch length increase with the decrease of GSM.2. If stitch length increase then fabric width increase

and WPI decrease.3. If machine gauge increase then fabric width

decrease.4. If yarn count increase then fabric width increase.5. If shrinkage increases then fabric width decrease

but GSM and WPI increase.6. For finer gauge, finer count yarn should use.7. Grey GSM should be less than finish GSM.

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The following equations for the selection of yarn count to get required G.S.M. equations vary for fabric types, fabric construction. List of equations are tabulated below:

• Single jerseyYarn count = - 0.141 GSM + 50.22

• PiqueYarn count = - 0.146 GSM + 57.16

• Double lacosteYarn count = - 0.167 GSM + 64.36

• 1 x 1 RibYarn count = - 0.123 GSM + 54.57

• Lycra 1 x 1 RibYarn count = - 0.119 GSM + 59.12

• Lycra 2 x 2 RibYarn count = - 0.108 GSM + 56.62

• InterlockYarn count = - 0.206 GSM + 80.56

• Single jerseyGSM = -6.879yarn count + 350.4

• Lycra Single jerseyGSM = -4.9716 yarn count + 354.56

• PiqueGSM = -6.6737 yarn count + 386.44

• 1 x 1 RibGSM = -7.9731 yarn count + 437.66

• Lycra 1 x 1 RibGSM = -8.2839 yarn count + 494.08

• Lycra 2 x 2 RibGSM = -8.2839 yarn count + 494.08

• InterlockGSM = -4.778 yarn count + 388

EQUATIONS FOR GETTING REQUIRED GSM FROM THE SPECIFIC YARN COUNT:

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Relation among GSM, stitch length and yarn count can be derived from the following equation

1GSM α (When Yarn count and Stitch length

bothYarn count x Stitch length are variable)

• Different properties were found in Different knit structures according to stitch length, stitch density that means wales per inch, course per inch. Loose structure that means higher loop length gives less GSM on fabric & compact structure that means shorter loop length gives high GSM on fabric.

• In our project analysis, we observed that single jersey plain structure & 1×1 plain rib structure variation of calculated GSM with respect to actual GSM is too small. But in single lacoste & polo-pique structure variation of calculated GSM with respect to actual GSM is high. Because single lacoste & polo-pique structure are made by combination of knit & tuck loops. They also analyzed that one knit loop consumes 30% more yarn than tuck loop. So calculated GSM is higher in single lacoste & polo-pique structure than single jersey plain structure & 1×1 plain rib structure.

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SOME FABRIC’S GSM IS SHOWED WITH SOME FABRIC’S GSM IS SHOWED WITH CHANGING YARN COUNTCHANGING YARN COUNT

SI. No. Fabric Type Yarn Count SL (mm) GSM1. Strip S/J 26/1 2.86 1602. S/J 30/1 2.80 1503. Double Pique 32/1 2.58 1654. 1/1 Rib 30/1 2.60 2205. 1/1 Rib 20/1 3.20 2706. 1/1 Rib 24/1 2.90 2207. 1/1 Rib 28/1 2.67 2008. 1/1 Rib 32/1 2.45 2009. S/J 28/1 2.78 155

10. S/J 40/1 2.45 11011. S/J 28/1 2.75 16012. Full Feeder Lycra S/J 34/1 2.90 18013. Full Feeder Lycra S/J 30/1 2.95 20014 Full Feeder Lycra S/J 28/1 2.80 16015. Full Feeder Lycra S/J 26/1 2.90 16016. 1/1 Rib 24/1 3.00 27017. 1/1 Rib 40/1 cvc 2.80 25018. 2/2 Rib 30/1 2.78 22019. 1/1 Lycra Rib 30/1 + 40D 2.90 23020. Strip S/J 26/1 2.86 160

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RESULT & DISCUSSIONRESULT & DISCUSSIONFrom our project work we manage to find the following equations for the

selection of yarn count to get required G.S.M. equations vary for fabric

types, fabric construction. The equations are tabulated below:

Relation between the fabric GSM and the yarn count:

If the GSM of the fabric is “x” and the count of yarn is “y”, then the

equation for determining GSM and the Yarn count is as follows:

GSM, x = 332 - 5.88y &  Yarn count (Ne), y = 56 - 0.17x

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CONCLUSIONAbout this project learning thing is that fabric GSM change during production. Different type of yarn and Yarn count has vary the fabric GSM. It is also vary with stitch length, dyeing and VDQ pulley. These parameters are responsible for GSM change. From this project try to input some information for how GSM depends on any other parameters.

So these things are should learn well to avoiding upcoming problem and increase productivity.

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