KEY WORD
G.S.M. Yarn Count. Stitch length. Yarn Diameter. Fabric Width. Machine gauge. Needle gauge. Wales space. Needle pitch.What is fabric?
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 Study basically is on knitted fabric specification and machines which are related to
knitted fabric production.
How we analyze fabric?
In the analysis of woven fabric specification we consider ends per inch, picks per inch, yarn count (warp & weft), and fabric width
In case of knitted fabric specification GSM,
stitch length
is mainly considered.Target of this training
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 for required G S M By this process we can get decision about yarn count, loop length, machine gauge, and
Aims of the Training
Find out relation between yarn count and GSM. Find out the logic of selection of stitch length.
Selection of machine diameter and machine gauge to get specific width of fabric. Find out the finished fabric width.
TERMINOLOGY AND DEFINITION
WALES PER INCH: Wales per inch means how many numbers of Wales are present in one inch, it is very important for calculation of knitted fabric GSM and fabric properties.
COURSES PER INCH: Courses per inch mean how many numbers of courses are present in one inch. It is also very important for calculation of knitted fabric GSM.
STITCH LENGTH: Stitch length is theoretically a single length of yarn which include one needle loop and half the length of Yarn (half of a sinker loop) between that needle loop and the adjacent needle loops on either side of it. Loop exists in course in course length and it is that which influence fabric dimension and other properties including weight.
MEASUREMENT OF YARN COUNT:
A different way to find out the count of the yarn. At first unravel a considerable no yarn from the fabric. Then measure 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: Count = n * L * 453.6
Wt *36* 840
Where, n= number of yarn in bundle. L= length of yarn.
MEASUREMENT OF GSM:
GSM = Ks * Tex
Stitch length (mm)
Stitch length = Ks * Tex GSM
Ks = GSM * Stitch length
Tex
Where, Ks is a constant. Its value is different for different fabric structure and fabric type. There are two formulas for calculating the GSM of a knitted fabric. i.e. First formula is GSM = Course per inch * Stitch length * 39.37 * 39.37 * Tex
1000 * 1000 GSM = WPI * CPI * SL(mm)
Count (Ne) x 0.9155 CPI = Count (Ne)*GSM
WPI * SL (mm) x 0.9155
Some reference for Ks value
Fabric Type Color Value of Ks
Single jersey Average 19.55
Single lacoste Average 22.4
Double lacoste Average 22.75
Polo pique Average 25
Plain interlock Average 39.3
1×1 Rib Light 24.5
1×1 Rib Average 26.5
Flat back rib Average 81
3 Thread fleece Average 40.92
To find suitable yarn count for Required GSM
Name of the fabrics Equations
Single jersey Yarn count = (-) 0.141 GSM + 50.22
Pique Yarn count = - 0.146 GSM + 57.16
Double lacoste Yarn count = - 0.167 GSM + 64.36
1 x 1 Rib Yarn count = - 0.123 GSM + 54.57
Lycra 1 x 1 Rib Yarn count = - 0.119 GSM + 59.12
Lycra 2 x 2 Rib Yarn count = - 0.108 GSM + 56.62
Interlock Yarn count = - 0.206 GSM + 80.56
To find suitable GSM for yarn count
Name of the fabrics Equations
Single jersey GSM = -6.879yarn count + 350.4 Lycra single jersey GSM = -4.9716 yarn count + 354.56
Pique GSM = -6.6737 yarn count + 386.44
1 *1 Rib GSM = -7.9731 yarn count + 437.66
Lycra 1 * 1 Rib GSM = -8.2839 yarn count + 494.08
Lycra 2 * 2 Rib GSM = -9.1216 yarn count + 519.05
EQUATION FOR DETERMINING FABRIC WIDTH:
Fabric width = No. of wales * Wales space.
= No. of needle * Wales space.
= πDg * Wales space
D= Cylinder diameter.
g = Gauge.
Fabric width = No. of needle
FOR CALCULATING YARN DIAMETER:
In case of minimum loop length there is no space left in interloping area.
i.e. stretched due to tension the wales space become less than 4d (d is the yarn diameter) When loop length is increased the space into the interloping area are increased as a result
wales space becomes wider. It may be up to 5.2d
D= 0.91
√ne
D = √Tex
26.7
Fabric Type Yarn count Stitch length (mm) Colour M/c DIA M/c Gauge Finished diameter (inch) Finished GSM Plain S/j 18s/1 2.94 White 26 24 30 220-230 20s/1 2.98 White 30 24 33.5 200-210 24s/1 2.68 White 30 24 32 175-185 26s/1 2.66 White 30 24 31 160-170 28s/1 2.70 Average 26 24 25 150-160 30s/1 2.68 Average 30 24 30 130-140 34s/1 2.40 Average 26 24 24 125-135 40s/1 2.44 Average 24 24 20 100-110 Single lacost 18s/1 3.00 Average 30 24 46 245-255 24s/1 2.64 Average 30 24 40 210-215 26s/1 2.60 Average 30 24 36 200-210 30s/1 2.50 Average 30 24 34 180-190
