Theory
Stitch density: Stitch density is a measurement of the number of needles that enter a square centimeter or a square inch of fabric as it passes from the entrance of a needle loom to the exit. This is determined by the number of needles on the boards and the number of strokes of the loom. A modern loom will have a computer readout for this number. Usually we have to tell the computer how many needles per meter are on the boards when we just install the loom. After that, it will continuously keep tracking the stitch density and display it on the screen.
GSM: GSM means grams per square meter, that is the weight of fabric in grams per one square meter. By doing this, we can compare the fabrics in a unit area that is heavier and which is lighter. GSM is one kind of specification of fabric that is very important for a textile engineer for understanding and production of fabric.
Objectives
- To know about the stitch density of the fabric
- To know about GSM of fabric.
- Learn about the formula of GSM and stitch length and density.
Apparatus
- Fabric
- Scissors
- Scale etc.
Working Procedure
- First, collect the sample.
- Then cut the sample from the fabric according to the dimension of 1 m of wales wise and course wise.
- Then open the yarn from the wales wise.
- Separated the yarn of 1 m in wales wise.
- Then counted the number of yarn.
- Then find out the number of yarn course-wise also.
- After that, used the formula to find out the value of stitch density and GSM.
Calculation
Stitch density = (WPI ✕ CPI) = (38 ✕ 48) = 1824 lbs/sq. Inch
Stitch length = (Length of 38 wales in cm ✕ 10) / Total no of wales = {(8.5 ✕ 10) / 38} = 2.24 mm
GSM = [{WPI ✕ CPI ✕ (39.37)2 × Stitch length (mm) ✕ Yarn count in Tex} / (1000 ✕ 1000)]
= [{38 ✕ 48 ✕ (39.37)2 ✕ 2.24 ✕ 18.44} / (1000 ✕ 1000)] = 116.77 = 117 gm/m2