# Textile Calculation

## Different Formulas of Weaving Calculation

Different Formulas of Weaving Calculation
Raju Tex
Production Executive,
B.J.Group, Mawna, Gazipur
Chittagong Textile Engineering College

Weaving Calculations:
The process of producing a fabric by interlacing warp and weft threads is known as weaving. The machine used for weaving is known as weaving machine or loom. Weaving calculation is very important to produce fabric. It is also very critical task for weaving master. Different formulas and calculation of weaving are given in this article.
 Weaving process
Different Formulas of Weaving Calculation:

Reed Count
It is calculated in stock port system.No. of dents in 2 inches is called Reed Count.

EPI
Reed count = ……………………..
1 + Weft crimp percentage

Reed Width

100 + Weft crimp percentage
Reed Width = Cloth width X ………………….....................…
100

Cloth Cover Factor

EPI
1. Warp cover factor = …………………….
√Warp Count

PPI
2. Weft cover factor = ……………………..
√Weft Count

Wp.C.F. X Wt.C.F.
3. Cloth cover factor = Wp.C. - F Wt.C.F + …………………………
28

Crimp % :
Crimp Percentage is defined as the mean difference between the straightened thread length and the distance between the ends of the thread while in cloth, expressed as a percentage.

Warp length - Cloth length
Warp crimp% = …………………………….. X 100
Cloth length

Weft length - Cloth length
Weft crimp% = …………………………….. X 100
Cloth length

Loom:

Motor pully diameter
Loom Speed = Motor RPM X …………...…………..
Loom pully diameter

Actual Production
Loom Efficiency (%) = ………………………….. X 100
Calculated Production

Fabric Specification:

EPI X PPI
Fabric specification = …………………………. X Fabric width
Warp count X weft count

Or

Warp count X weft count
Fabric specification = …………………………. X Fabric width
EPI X PPI

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.)

Total No. of Ends X Tape Length in Yds.
Where as Weight of warp in lbs. = ……………………………………………………..
840 X Warp Yarn Count

Length of Cloth (Yds) X Picks / inch in Cloth X Reed Width (inch)
Also Weight of weft in lbs.= ……………………………………………………………………….
840 X Weft Yarn Count

Weving Calculations:
Calculating linear yards of fabric produced on a weaving machine per hour of operation can be done using the following formula:

Linear Yards/Hour = (picks per min. / picks per in.) x (60 min. per hr. / 36 in. per yd) x loom efficiency (%)

Linear Meters/Hour = (picks per min / picks per centimeter) x (60 min. per hr. / 100 cm per meter) x loom efficiency (%)

Square Yards/Hour = Linear Yards Per Hour x Fabric Width (Yds.)

Square Meters/Hour = Linear Meters Per Hour x Fabric Width (Meters)

Rate of Filling Insertion (Yards/Min) = Loom Speed (Picks/Min) x Loom Width (Yds.) x Loom Efficiency (%)

Rate of Filling Insertion (Meters/Min) = Loom Speed (Picks/Min) x Loom Width (Meters) x Loom Efficiency (%)

Exmple of Weving Calculations:

Example-1:
What are the linear yards of fabric produced on a machine running 650 picks per minute, inserting 58 picks per inch, and operating at a 92% efficiency?

Linear Yards/Hour = (picks per min. / picks per in.) x (60 min. per hr. / 36 in. per yd) x loom efficiency (%)

Linear Yards/Hour = (650picks per min. / 58picks per in.) x (60 min. per hr. / 36 in. per yd) x .92 loom efficiency