GSM

GSM means the weight in gram per square meter of fabric.
Fabric area density can be calculated by the following formula,

Here, T = Tex, S = Stitch density,
l= Stitchlength
GSM is one of the primary parameters for determining fabric quality and GSM depends on WPI, CPI, yarn count (Ne) and stitch length.The GSM cutter isvery popular and easy usable GSM testing instrument used in most of the knittingfactories.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.
Technical formula used for GSM calculation,

The equation for GSM can be formulated by using equation of WPI & CPI formulated here.
The general formula for calculating GSM is

Figure 6 shows the variation of Actual GSM and GSM from derived equation for  single jersey grey fabrics made of 100% cotton at standard condition.

Figure 7 shows a relative presentation of actual and calculated GSM when required GSM is 130.The analyzed data shows that the error percentage for calculated GSM is below 5% in most of the time. And this variation of GSM is related with so many factors like: color, yarn count, tightness factor, relaxation state, andprocessesoccurred onthe fabric.

The equationof GSM contains the constant ‘R’ &statistical analysis for the values of R for 100% cotton single jersey fabric foundfrom analyzed data shows 1.46% standard deviation when mean value is 1.273 at table 4.