Relation between yarn count, fabric type, machine dia, stitch length and finished GSM

Yarn count is the numerical expression which indicates or expressed the fineness or coarseness of yarn. According to Textile Institute, Count a number indicating the mass per unit length or the length per unit mass of yarn.

Yarn Count Range

Fabric	Count
Cotton	20/1, 24/1, 26/1, 28/1, 30/1, 34/1, 40/1 Ne
Terylene cotton (a synthetic polyester fibre or fabric based on terephthalic acid)	20/1, 24/1, 26/1, 28/1, 30/1 Ne
CVC	26/1, 28/1, 30/1, 34/1 Ne
Melange	20/1, 22/1, 26/1, 30/1 Ne
Spandex	40D, 70D
Polyester	75D, 150D
Sewing thread	40/2, 150D

Stitch length (knitting) is the length of yarn in a knitted loop.

Stitch length is theoretically a single length of yarn which includes one needle loop half the length of yarn (half of a sinker loop) between that needle loop and the adjacent needle loops on either side of it. Loop exists in coarse length and it is that which influence fabric dimensional and other properties including weight. In the knit stitch on the left, the next (red) loop passes through the previous (white) loop from below, whereas in the purl stitch (right), the next stitch enters from above. Thus, a knit stitch on one side of the fabric appears as a purl stitch on the other, and vice versa.

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.

Following charts will show the relation between yarn count, fabric type, machine dia, stitch length and finished GSM

Fabric Type	Yarn count	Stitch length (mm)	Color	D×G	Finished diameter(inch)	Finished GSM
Plain S/j	18S/1	2.94	white	26×24	30	220-230
Plain S/j	20S/1	2.98	white	30×24	33.5	200-210
Plain S/j	24S/1	2.68	white	30×24	32	175-185
Plain S/j	26S/1	2.66	white	30×24	31	160-170
Plain S/j	28S/1	2.70	Avg	26×24	25	150-160
Plain S/j	30S/1	2.68	Avg	30×24	30	130-140
Plain S/j	34S/1	2.40	Avg	26×24	24	125-135
	40S/1	2.44		24×24	20	100-110

  

Fabric Type	Yarn count	Stitch length (mm)	Color	D×G	Finished diameter(inch)	Finished GSM
Single lacost	18S/1	3.00	Avg	30×24	46	245-255
Single lacost	24S/1	2.64	Avg	30×24	40	210-215
Single lacost	26S/1	2.60	Avg	30×24	36	200-210
Single lacost	30S/1	2.50	Avg	30×24	33	180-190

Fabric Type	Yarn count	Stitch length (mm)	Color	D×G	Finished diameter(inch)	Finished GSM
1 × 1 Rib	26S/1	2.50	Avg	30×18	40	240
1 × 1 Rib	24S/1	2.75	Avg	30×18	41	235
1 × 1 Rib	26S/1	2.54	Avg	40×18	40	245
1 × 1 Rib	26S/1	2.55	Avg	40×18	47	235
1 × 1 Rib	26S/1	2.65	Avg	32×18	32	230
1 × 1 Rib	24S/1	2.95	Avg	34×18	32	220
1 × 1 Rib	24S/1	2.90	Avg	40×18	38	225
1 × 1 Rib	28S/1	2.40	Avg	30×24	38.5	232

ü  If the fabric is to be Enzyme washed, the stitch length should be kept (10%) less than the normal range. Because, enzyme wash reduces the total weight of the fabric by removing the floating fibre and hairy fibre.

ü  For average color, the finished GSM varies 2-4%.

ü  If the GSM varies 25-30%, it is not only necessary to control the VDQ pulley dia but also yarn tension & take-up roller