GREY GSM VS FINISHED GSM

Grey GSM VS Finished GSM of knit fabric
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After receiving the yarn we knit the yarn in knitting machine for producing knit fabric. At this stage the fabric remains uncolored formed. We called this as Grey Fabric. Then we dye the grey fabric in dyeing winch (machine) as per our required color.

In this regards the please note that, GSM of the followings Grey fabric are not remain same as our require finished fabric GSM. Normally the GSM of grey fabric remains lower than the finished fabric. After knitting when we dye and washed the fabric then the GSM increase and come to near as our requirement. This increasement of GSM depends on fabric constructions & some knitting variables. Let's see an example

Say,
Fabric Construction: Single Jersey
Yarn Count : 30/s
Require GSM(finished): 145 GSM
Grey GSM : will be what?

As per practical experience we know for Single Jersey fabric, if we knit the fabric with 30/s yarn then the grey GSM  will increase 15% to 20% after dyeing and finishing.

So, if we need 145 GSM S/J fabric with 30/s
Then we should keep the

Grey GSM = 145 – (15 to 20%), supposed it the percentage will be 18 then
Grey GSM = 145 – 18%
Grey GSM = 119 GSM

So, now we know that, if we need 145 gsm single jersey fabric with 30/s yarn, then we should keep the GSM of grey fabric as 119.

Please find below the GSM different between Grey VS Finished for some more types of fabric.
  
For single jersey fabric:

If the yarn count is 30/s then the grey gsm will be 20% to 15% less from the finished Gsm

If the yarn count is 26/s then the grey gsm will be 22% to 20% less from the finished Gsm

If the yarn count is 24/s then the grey gsm will be 24% to 23% less from the finished Gsm

If the yarn count is 20/s then the grey gsm will be 24% to 21% less from the finished Gsm
CALCULATION OF GSM
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Dear All,

GSM means the weight in gram per square meter of fabric.GSM is a very important parameter for specified a certain quality of knitted fabric. The production of knitted fabric is calculated in weight. The GSM cutter is very popular and easy usable GSM testing instrument used in most knitted factory. But the construction of this cutter is very simple. It is circular disk of 100 square cm area with sharp blade attached to its edge. So 100 square cm of fabric can easily cut by it and weighted at the electric balance to get GSM reading.

There are two formulas for calculating the GSM of a knitted fabric

First formula is as under:

               Course per inch X Stitch length X 39.37 X 39.37 X Tex
GSM =    ----------------------------------------------------------------------
                                               1000 X 1000

aNd

                WPI X CPI X SL(mm)
GSM =    ---------------------- X 0.9155
                         Count(Ne)

CALCULATION OF WALES PER INCH (WPI):

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 (CPI):

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 (SL mm):

Stitch length is theoretically a single length of yarn which includes one needle loop and adjacent needle loops on either side of it. Loop exits in course in course length and it is that which influence fabric dimension and other properties including weight.

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.

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 x L x 453.6
Count =   ----------------
                 Wt x 36 x 840
Where,

N   = number of yarn in bundle.
L    = length of yarn.
Wt  = weight of yarn.

Another formula is the following:

                    Ks x Tex
GSM =   ---------------------
              Stitch length (mm)

Where,
Ks is a constant. Its value is different for different fabric structure and fabric type. Ks is calculated and estimated as below:

              GSM x Stitch length
Ks =     -----------------------------
                          Tex

How do calculate Kg from Yards (Knit fabric)
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From this post we will learn how to calculate Kgs from Yards.

Say,

Fabric length  - 3.3611 yards ( 121 ")
Fabric Width - 45 "
Fabric Gsm - 140

Rules:

= Fabric length X Fabric width X GSM / 1550 / 1000

= 121" X 45" X 140 /1550 / 1000

= 762300 /1550 /1000

= 0.49180645161 kgs (weight of the followings fabric)

Hope above information will help you