# Weaving Calculations

A guide to calculations relating to yarn and cloth and all processes of weaving.It includes reed count, reed width, Maximum EPI for a particular count, weave density, crimp percentage, cloth cover factor etc.

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
Crimp %age = {(Warp length – Cloth length)/Cloth Length}* 100
Crimp %age = {(Warp width – Cloth width)/Cloth width}* 100
4. Cloth Cover Factor
1. Cloth Cover Factor = Wp.C.F +Wt.C.F. – {(Wp.C.F. – Wt.C.F)/28}
5. Maximum EPI for particular count
1. other design = (Ends /Repeat * 1/Yarn Diametre)/ (No of intersections/repeat+ ends/repeat)
6. Warp Density

• = <350
• Weave Density = 50+{(Warp Density – 100) * F.D – 100} /{(Weft Density – 100)* F.D – 100}
• Effective Weave Density = W. D x K of loom width x K of Design
= < 72
Wp / filling – K Loom Width – K Weave Design – K
Cotton = 1.00140 cm – 0.99Plain1/1 = 1.00
Polyester/Cotton = 1.03180 cm – 1.00Twill 1/2 = 0.87
Viscose Filament = 1.17190 cm – 1.01Matt, Gabardine 2/2 = 0.82
Polyester Filament = 1.22220 cm – 1.02Drill 1/3 = 0.77
250 cm – 1.08Satin 1/4 = 0.69
330 cm – 1.15
360 cm – 1.20

To change the count and the number of thread/inch, keeping the same denseness of fabric

To change the count without altering the denseness of the fabric
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

Warp requirement to weave the cloth

• Warp weight in grams /metre = {(Total Ends * 1.0936 * 453.59 * crimp %)/(840 * count)} * wastage %
• Weft weight in grams /metre ={(R.S. in inches * 453.59 * PPI)/(840 * count)} * wastage % * crimp %
• 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

• Warp weight in grams /metre ={(Total Ends * count (Denier) )/9000} * wastage % * crimp %
• 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

Fabric Production Calculation

• Loom Speed = Motor RPM * (Motor Pully Diametre)/(Loom Pully Diametre)
• Loom Effeciency Percentage = (Actual Production/Calculated Production )* 100
• Moisture Regain Percentage = {(Yarn Weight – Dried Yarn Weight)/Dried Yarn weight} * 100
• Moistue Content Percentage = {(Yarn Weight – Dried Yarn Weight)/Yarn weight} * 100
Type of YarnMoisture Regain %Moisture Content %
Cotton8.507.83
Jute13.7512.10
Silk11.009.91
Rayon, Viscose11.009.91
Wool17.0014.50
Nylon4.203.78
• Warp Weight in Kg = (Total Ends * Tape Length in meters)/(1693.6 * Warp Count)
• Weft Weight in Kg = (R.S in centimetres * cloth length in metres * PPI )/(4301.14 * weft Count)
• Cloth weight in GSM = {EPI/Warp Cout)+(PPI/Weft count)}* 25.6
• oz (ounce ) per sq. yard = GSM(Grams per sq. meter)/34

• Material Measurement
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)
• The weight of yarn in a cloth
The weight of cloth manufactured on looms depends upon the weight of yarns in the warp 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 in-lbs.)
Whereas Weight of warp in lbs. = (Total No. of Ends * Tape Length in Yards)/(840 * warp yarn count)

Also

• Drucilla Malabanan

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• sunil

What should be the width of dip fabric meant for tyre manufacturing to be maintained so that after rubber coating EPI will not change
Regards
Sunil

• Akthar Hussain

How to calculate fabric weight per meter using 40 warp,60 weft, reed 58,pick 56,width 48 inches
Can you please suggest the formula and how to use it

• Kiruthika

Hi,
How to calculate the leno/bobin yarn consumption for required metres?

• Nabeel Jamal

what is EPI & PPI