Some important Weaving Calculations

1.Reed Count
…………………………..
It is calculated in stock port system.No. of dents in 2 inches is called Reed Count.
Reed Count = EPI/(1 + Weft crimp %age)

2.Reed Width
………………………..
Reed Width = Cloth Width *(100+ weft crimp %age)/100

3.Crimp Percentage
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a. Crimp %age = {(Warp length – Cloth length)/Cloth Length}* 100
b. Crimp %age = {(Warp width – Cloth width)/Cloth width}* 100

4.Cloth Cover Factor
……………………………….
1.Warp cover factor=EPI/(warp count)^1/2 (^ 1/2 means root over)

2.Weft cover factor=PPI/(weft count)^1/2 ( ^1/2 means root over)

Cloth Cover Factor = Wp.C.F +Wt.C.F. – {(Wp.C.F. – Wt.C.F)/28}

5.Maximum EPI for particular count
…………………………………………………..
a. For plain fabrics =14* (count)^1/2 (^ 1/2 means root over)

b. For drill fabrics = 28*4/6*(count)^1/2

c. For satin fabrics =28*5/7*(count)^1/2

d. other design = (Ends /Repeat * 1/Yarn Diametre)/ (No of intersections/repeat+ ends/repeat)
e. Yarn diameter=1/28*(count)^1/2

6.Warp Density
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a. Warp density=Ends per cms*(Tex*K)^1/2

b. weft density=Picks per cms*(Tex*K)^1/2

c. Weave Density = 50+{(Warp Density – 100) * F.D – 100} /{(Weft Density – 100)* F.D – 100}

d. Effective Weave Density = W. D x K of loom width x K of Design

Wp / filling – K—————– Loom Width – K —————— Weave Design – K
……………………….. ……………………………. ………………………….
Cotton = 1.00———————–140 cm – 0.99————————Plain1/1 = 1.00
Polyester/Cotton = 1.03————-180 cm – 1.00———————–Twill 1/2 = 0.87
Viscose Filament = 1.17————190 cm – 1.01———Matt, Gabardine 2/2 = 0.82
Polyester Filament = 1.22———220 cm – 1.02————–Drill 1/3 = 0.77
————————————–250 cm – 1.08————–Satin 1/4 = 0.69
————————————–330 cm – 1.15
————————————–360 cm – 1.20

7.To change the count and the number of thread / inch , keeping the same denseness
………………………………………………………………………………………………….
of fabric
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To change the count without altering the denseness of the fabric

a. EPI in Exp.cloth = (EPI in exp.Cloth2/EPI in given cloth) * count in given cloth
To change the EPI without altering the denseness of the fabric

b. EPI in Exp.cloth = EPI in given cloth * (warp count in Exp.colth)^1/2 /(warp count in given count)^1/2

8.Warp requirement to weave the cloth
…………………………………………………
a.Warp weight in grams /metre = {(Total Ends * 1.0936 * 453.59 * crimp %)/(840 * count)} * wastage %

b.Weft weight in grams /metre ={(R.S. in inches * 453.59 * PPI)/(840 * count)} * wastage % * crimp %

c.Cloth length in metres with given weft weight=( weft weight in kgs * weft count * 1848 * 0.9144)/(PPI * R.S in inches)

For silk and Polyester
—————————-
a.Warp weight in grams /metre ={(Total Ends * count (Denier) )/9000} * wastage % * crimp %

b.Weft weight in grams /metre = {(R.S in inches * count(Denier)* PPI)/9000}* wastage % * crimp %

Allowance for count in bleached and Dyed fabric
1.Count becomes 4%
2. FinerDyed counts become max 6% Coarser

9.Fabric Production Calculation
……………………………………………

a.Loom Speed = Motor RPM * (Motor Pully Diametre)/(Loom Pully Diametre)

b.Loom Effeciency Percentage = (Actual Production/Calculated Production )* 100

c.Moisture Regain Percentage = {(Yarn Weight – Dried Yarn Weight)/Dried Yarn weight} * 100

d.Moistue Content Percentage = {(Yarn Weight – Dried Yarn Weight)/Yarn weight} * 100

Type of Yarn———————Moisture Regain %—————Moisture Content %
Cotton——————————-8.50——————-————–7.83
Jute————————–——-13.75——————————–12.10
Silk————————–———11.00—————-—————9.91
Rayon, Viscose———————-11.00————————–——9.91
Wool————————–——–17.00—————–————14.50
Nylon ———————————-4.20———————-———3.78

a. Warp Weight in Kg = (Total Ends * Tape Length in metres)/(1693.6 * Warp Count)

b. Weft Weight in Kg = (R.S in centimetres * cloth length in metres * PPI )/(4301.14 * weft Count)

c. Cloth weight in GSM = {EPI/Warp Cout)+(PPI/Weft count)}* 25.6

d. oz (ounce ) per sq. yard = GSM(Grams per sq. metre)/34

10.Material Measurement
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To calculate the length of any rolled fabrics, this formula gives the nearest accuracy.

L = {0.0655(D-d)(D+d)}/t
Where L = Length of material (Feet) t = Thickness of fabrics (inches)
D = Outside diameter (inches) d = Inside diameter (inches)

11.Weight of yarn in a cloth
………………………………….
The weight of cloth manufactured on looms depends upon the weight of yarns in thewarp and weft: ends/inch, picks/inch and the weight of size on the warp.

Therefore,
Cloth weight = Weight of warp + Weight of weft + Weight of size (All inlbs.)
Where as Weight of warp in lbs. = (Total No. of Ends * Tape Length in Yards)/(840 * warp yarn count)

Also

Weight of weft in lbs= Length of cloth (yards) *pick per inch in cloth*Reed width(inch) / 840*count

Some important Weaving Calculations
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