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Determination of GSM (Gram per Square Meter) of Woven and Knitted Fabrics
Name of the Experiment: Determination of GSM of woven and knitted f abrics. Introduction: T he GSM of fabric is one kind of specif ication of f abric which is very important f or a textile engineer f or understanding and production of f abric. GSM means Gram per square meter that is the weight of f abric in gram per one square meter. By this we can compare the f abrics in unit area which is heavier and which is lighter. Objectives: 1. To determine the GSM of the given samples of f abric. 2. To compare the GSM of them. T heory: T he weight of a f abric can be expressed in two ways, either as the weight per unit area or the weight per unit length; the f ormer is self explanatory but the latter requires a little explanation because the weight of a unit length of f abric will obviously be af f ected by its width. In woven f abric, the weight per unit length is usually ref erred to as the weight per running G SM Cutte r yard. It is necessary theref ore to know the agreed standard width upon which the weight per running yard is based. Usually this width depends upon the width of loom. Bef ore coming the term GSM there was another term called lb/100 yards. T his expression is used by British Standard. For measuring this there are a template and a quadrant balance. T he template area is 1/100 square yards of which each arm is 1/10 yards in length. For measuring GSM, a GSM cutter is used to cut the f abric and weight is taken in balance. Both of these measurement and method is equally used f or both woven and knitted f abrics. Apparatus: 1. Template 2. Quadrant balance 3. Scissor 4. GSM cutter 5. Electric balance. Sample: 1. Finished cotton woven f abric 2. Finished cotton knitted f abric.
Atmosphere: Temperature 25oC and relative humidity 67% Standard atmosphere: temperature 20oC and relative humidity - 65%. M/c specification: Name: Quadrant balance Brand: Good brand & Co. Ltd. Scale: 100 yards f or f abric. Working Procedure: 1. For measuring with Quadrant balance, at f irst we should cut the f abric sample according to the template area. By this way we cut 10 woven samples and 10 knitted samples. 2. Now weigh these samples in pounds by quadrant balance according to 100 yards scale. 3. By this way we get the weight in pound per 100 square yards f abric. 4. For Measuring GSM, we should cut the f abric sample by GSM cutter. By this way cut 10 woven samples and 10 knitted samples. 5. Now weigh these samples by electric balance in grams. 6. By this way we get the weight in gram per one square meter f abric. 7. Now f ind out the average of these f ound weights. 8. For woven f abrics f ind out the weight per running yards assuming the loom width 48 inches. Data:
Type Sl No. 1 2 3 4 5 Average
Woven Fabric lb/100 yd 2 20 19 19 19 18 19.2 gm/meter 2 107.64 107.64 104.75 102.86 102.86 106.83
Knitted fabric lb/100 yd 2 38 37 35 38 36 36.8 gm/meter 2 144 144 149.67 143.81 148 145.37
Calculation: For measuring the weight of woven f abric in weight per running yards, f orm data table we get the weight of 100 yd2 f abric is 19.2 lbs. Now assume the width of loom is 48 inches. T heref ore the area of the f abric will be 1.33 yd2. So, Weight of 100 yd2 woven f abric = 19.2 lbs. Weight of 1.33 yd2 woven f abric = 0.255 lbs. T hat is weight of f abric per running yard is 0.255lbs or 116 gms. Result:
1. T he weight of woven f abric is 19.2 lbs/100 yd2 or 106.83 GSM. 2. T he weight of knitted f abric is 36.8 lbs/100 yd2 or 145.37 GSM. 3. T he weight of woven f abric per running yard is 0.255lbs or 116 gms. Remark: T his is a direct measuring tester. So the result should be accurate. But as the samples are of both cotton f abrics, so there are ef f ects of moisture content on the weight of f abrics. Besides the knitted f abrics are very much extensible and proper relaxed state is quite dif f erent during cutting of sample with GSM cutter. T heref ore there are variations among their weights. T he ef f ects of moisture content can be accounted f or either by conditioning the specimen in the standard atmosphere or by taking the specimen to oven dry weight and adding the of f icial regain. 52 0 2 0 1 1805
