The GSM of fabric is one kind of specification of fabric which is very important for a textile engineer for understanding and production of fabric. ‘GSM’ means ‘Gram per square meter’ that is the weight of fabric in gram per one square meter. By this we can compare the fabrics in unit area which is heavier and which is lighter.

Objectives:

To determine the GSM of the given samples of fabric.
To compare the GSM of them.

Theory:

The weight of a fabric can be expressed in two ways, either as the ‘weight per unit area’ or the ‘weight per unit length’; In woven fabric, the weight per unit length is usually referred to as the ‘weight per running yard’. For measuring this there are a template and a quadrant balance. The 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 fabric and weight is taken in balance. Both of these measurement and method is equally used for both woven and knitted fabrics.

Let, M=Weight of (100×1) yd² fabric in lbs.

So, W=M/100 lb/yd²

Again, 1yd²= (0.9144)² m² = 0.84m²

1lb =453.6g

Apparatus:

Template
Quadrant balance
Scissor
GSM cutter
Electric balance.

Sample:

Finished cotton woven fabric
Finished cotton knitted fabric.

Atmospheric condition:

Wet condition: – 26 ° c. & Dry condition: – 30° c.
Difference between wet and dry bulb = 30° c-26 ° c. = 4° c
So, relative humidity (RH) = 70 %

M/c specification:

Name : Quadrant balance
Brand : Good brand & Co. Ltd.
Scale : 100 yards for fabric.

Procedure:

For measuring with Quadrant balance, at first we should cut the fabric sample according to the template area. By this way we cut 10 woven samples and 10 knitted samples.
Now weigh these samples in pounds by quadrant balance according to 100 yards scale.
By this way we get the weight in pound per 100 square yards fabric.
For Measuring GSM, we should cut the fabric sample by GSM cutter. By this way cut 10 woven samples and 10 knitted samples.
Now weigh these samples by electric balance in grams.
By this way we get the weight in gram per one square meter fabric.
Now find out the average of these found weights.
For woven fabrics find out the weight per running yards assuming the loom width 48 inches.

Data:

Sl	Wt. in lbs/100yds	Wt. in lbs/yd²	Wt in gm/yd²	Wt in gm/m² x	Aver.			S.D.	C.V.%
WOVEN FABRIC
1	19	0.19	86.18	102.59		4.32	18.66
2	20	0.20	90.72	108		1.09	1.188
3	20	0.20	90.72	108	106.91	1.09	1.188	4.9	4.58
4	19	0.19	86.18	102.59		4.32	18.66
5	21	0.21	95.26	113.4		6.49	42.12
	KNITTED FABRIC
1	25	0.25	113.4	135		2.16	4.66
2	25	0.25	113.4	135		2.16	4.66
3	24	0.24	108.86	129.6	132.84	3.24	10.5	2.64	2
4	25	0.25	113.4	135		2.16	4.66
5	24	0.24	108.86	129.6		3.24	10.5

Calculation:

G.S.M. of woven fabric = (102.59+108+108+102.59+113.4) / 5 =106.91
G.S.M. of knitted fabric = (135+135+129.6+135+129.6) / 5 =132.84

Results:

S.M. of given woven fabric =106.91
S.M of given knitted fabric =132.84

Remark:

This is a direct measuring tester. So the result should be accurate. But as the samples are of both cotton fabrics, so there are effects of moisture content on the weight of fabrics. Besides the knitted fabrics are very much extensible and proper relaxed state is quite different during cutting of sample with GSM cutter. Therefore there are variations among their weights. The effects of moisture content can be accounted for either by conditioning the specimen in the standard atmosphere or by taking the specimen to oven dry weight and adding the official regain.

Conclusion:

I would like to thank our respected teacher for the important instructions. I am also grateful to our lab assistants for their kind help. This experiment helps me to know about the weight of fabric per unit area that is very important for textile testing. I think this will be very helpful in my future life.

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