Weaving Calculations

Posted by Default on January 25, 2019 in

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.

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. 
   2. 
   3. Cloth Cover Factor = Wp.C.F +Wt.C.F. – {(Wp.C.F. – Wt.C.F)/28}
5. Maximum EPI for particular count
   1. 
   2. 
   3. 
   4. other design = (Ends /Repeat * 1/Yarn Diametre)/ (No of intersections/repeat+ ends/repeat)
   5. 
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 = 1.00	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

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 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

• • 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)

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