**Introduction**

A loom is a contact point of all the processes (ginning, opening, **carding**, **spinning**, **winding**, warping, sizing & beaming) of fabric production. These processes are done before weaving. A loom can not be said machine but it is a device which is used to produce woven fabric. There are various types of loom like Projectile loom, Rapier loom, Air jet & Water jet loom etc. The whole process of weaving is done through several motions. There are three main **loom motion**, which are- 1) Primary motion, 2) Secondary motion & 3) Tertiary motion. So, calculation play an important role in weaving process. Some important production calculation (**Fabric specification**, Weight of fabric, Loom production, Efficiency, Machine RPM etc.) of Loom are discussed below.

**Some Important Conversions for Production Calculation of Loom **

- 36 inch = 3 Feet = 1 Yard;
- 1 Meter = 1.0936 Yards;
- 1 Pound(lb) = 453.6 Gram = 16 Ounce (Oz);
- 1 Lea = 120 Yards;
- 840 Yard = 7 Lea = 1 Hank;
- 1 Pound (lb) = 7000 Grains;
- 1 Meter = 39.37 Inch;
- 1 inch = 2.54 cm;
- 1 cm = 10 mm;
- 1 Kg = 2.205 Pound (lb)

**Mathematical Problems of Loom Production Calculation**

**Fabric weight calculation:**

**…………………………………………….EPI x PPI**

**1. Fabric Specification: ———————————————- x Fabric Width**

**…………………………………Warp Count x Weft Count**

**……Warp Count x Weft Count**

**Or, ———————————————- x Fabric Width**

**……………..EPI x PPI**

**…………L x w**

**2. Ne = —————-**

**…………W x l**

……………………………………………………10 x 8

**Example:** Fabric Specification ———————- x 60”

…………………………………………………..70 x 50

Calculate the fabric weight of 1000 m.

**Solution:**

Warp Weight:

EPI = 70

Warp Count= 10

Fabric width = 60”

Total No of warp = 70 x 60 = 4200

Length of each end = 1000 m + 1000 x 3% [Crimp = 3%]

= 1030 m

Total Length of warp = 4200 x 1030 m

= 4326000 m

We know,

……….L x w

Ne = ————————

………W x l

Warp Length,

L = 4326000 m

Ne = 10

……………………………….L x w

Warp weight, W = ————————

………………………………Ne x l

….4326000 x 0.4536

= ——————————- kg

…..10 x 840 x 0.91

= 256.71 kg

Weft Weight:

PPI = 50

Weft Count = 8

Total no of weft = 50 x 39.37 x 1000 = 1968500

Fabric width = 60”

Length of each weft = 60” + 60 x 5% [crimp = 5%]

= 63” = 1.6 m

Total Length of weft = 1968500 x 1.6 m

= 3149600 m

…………………………L x w

We know, Ne = ————————-

………………………..W x l

Weft Length, L = 3149600 m

Ne = 8

……………………………..L x w

Weft Weight, W = ——————–

…………………………….Ne x l

…3149600 x 0.4536

= ——————————— kg

……8 x 840 x 0.91

= 233.62 kg

Now, Total Fabric Weight = Warp Weight + Weft Weight

= 256.71 + 233.62 kg

= 490.33 kg **(Ans)**

**Example:** Calculate the weight of yarn in fabric (warp & weft)

…20 x 22

—————- x 56” of 5000m fabric

…60 x 58

**Solution:**

In 5000 m fabric, weight of warp:

EPI = 60

Warp count = 20

Fabric width = 56”

Total no of warp = 60 x 56 = 3360

Length of each end = 5000m + 5000 x 7% [Crimp = 7%]

= 5350 m

Total Length of warp = 3600 x 5350 m

= 17976000 m

……………………….L x w

We know, Ne = ————————–

……………………….W x l

Length of warp, L = 17976000 m

Ne = 20

………………………………….L x w

Weight of warp, W = ————————-

…………………………………Ne x l

…17976000 x 0.4536

= —————————- kg

……20 x 840 x 0.91

= 533.35 kg

Weight of Warp yarn = 533.35 kg** (Ans)**

In 5000 m fabric, weight of weft:

PPI = 58

Weft Count = 22

Total no of weft = 58 x 39.37 x 5000

= 11417300

Fabric width = 56”

Length of each weft = 56” + 56 x 7% [crimp = 7%]

= 59.92” = 1.522m

Total Length of weft = 11417300 x 1.522 m

= 17377130.6 m

………………………..L x w

We know, Ne = ————————-

……………………….W x l

Weft Length, L = 17377130.6 m

Ne = 22

……………………………….L x w

Weft Weight, W = ———————

………………………………Ne x l

…17377130.6 x 0.4536

= ———————————– kg

……22 x 840 x 0.91

= 468.71 kg

Weight of weft yarn in 5000m fabric = 468.71 kg **(Ans)**

**Production calculation of loom:**

**………………………………………………..PPM**

**1. Fabric Production in Meter = —————- x 60 x No of Loom x Efficiency**

**…………………………………………………PPI**

**……………………………………………………PPM**

**2. Production per hour per loom = —————–**

**…………………………………………………….PPI**

**Example:** Calculate the fabric production in meter per shift of a weaving factory in which a day is divided into two shifts. The factory has two weaving sheds, each consists of 15 rapier looms. The produced fabric has following specifications-

….20 x 16

—————— 56” [Assume any necessary parameters]

…110 x 51

**Solution:**

Here, 1 Shift = 12 hrs

Each weaving shed consists of 15 looms

So, Total no of looms in two sheds = 15 x 2 = 30

PPI = 51

Assume, PPM = 200

M/C Efficiency = 90% = 0.9

………………………………………………………………PPM

Now, Fabric Production in Meter/Shift = —————– x 60 x 12 x No of Loom x Efficiency

……………………………………………………………….PPI

…200 1

= ——– x 60 x 12 x 30 x 0.9 x —————

….51 39.37

= 1936.38 meter/shift **(Ans)**

**Example:** Calculate the yarn consumption of a loom per hour running at 180 PPM for producing

…40 x 60

——————— x 56” fabric.

…72 x 48

**Solution:**

Here, PPM = 180

PPI = 48

……………………………………………………………PPM

Now production per hour per loom = ——————-

…………………………………………………………….PPI

…180 1

= ———- x 60 x ———- yds

….48 36

= 6.25 yards **(Ans)**

**Example:** Calculate the production of loom-

PPM = 350

PPI = 60

No of loom = 45

Time = 7 days

Efficiency = 90%

**Solution:**

……………………350 90 1

Production = ——— x 60 x 24 x 7 x 45 x ——— x ————– meter/7days

……………………60 100 39.37

= 60487.68 meter/7days **(Ans)**

Example: Find out production calculation of loom –

Crank shaft RPM = 60

No of Tappet = 3

PPI = 50

Efficiency = 80%

**Solution:**

PPM = Crank shaft RPM x No of Tappet

= 60 x 3 = 180

……………………………….180 80 60

Loom Production = ————— x ———– x ————- yards/hour

……………………………….50 100 36

= 4.8 yards/hour **(Ans)**

**Example:** Calculate the loom production –

No of bobbins = 250

Time = 30 days

Efficiency = 80%

PPM = 300

PPI = 82

**Solution:**

……………………………….300 x 60 x 24 x 30 x 260 x 80

Loom Production = ——————————————————- yds/30 days

…………………………………………..82 x 100 x 36

= 878048.78 yds/30 days **(Ans)**

**Machine efficiency and RPM calculation:**

**…………………………………………………Motor Pulley Dia**

**1. Machine RPM = Motor RPM x —————————————–**

**………………………………………………….M/C Pulley Dia**

**……………………………………Real time utility x 100**

**2. Loom efficiency (%) = ———————————————–**

**………………………………………….Shift time**

**Example:** Calculate the efficiency of loom-

PPM = 650

PPI = 58

No of loom = 10

Time = 35 days

Production = 110000 m

Efficiency, ⴄ = ?

**Solution:**

……………………650 x 60 x 24 x 35 x 10 x ⴄ

Production = ———————————————-

………………………….58 x 100 x 39.37

……Production x 58 x 100 x 39.37

ⴄ = ———————————————————

……….650 x 60 x 24 x 35 x 10

…110000 x 58 x 100 x 39.37

= ———————————————-

……650 x 60 x 24 x 35 x 10

= 76.77% **(Ans)**

**Example:** Calculate Machine RPM-

Motor RPM = 1440

Motor Pulley Dia = 3”

M/C Pulley Dia = 8”

**Solution:**

……………………………………………….Motor Pulley Dia

Machine RPM = Motor RPM x —————————————-

……………………………………………….Motor Pulley Dia

………………3

= 1440 x ——–

……………..8

= 540 **(Ans)**

**Example:** Calculate the loom efficiency and loom production-

Loom RPM = 700

PPI = 90

Time to mend warp breakages = 10 min

Weft breakages time = 5 min

Other stops = 10 min

Shift time = 8 hrs

**Solution:**

Total stoppage time = 10 + 5 + 10 = 25 mins

So real time utility = 8 hrs – 25 mins

= 7 hour 35 mins

= 7.583 hrs

…………………………….Real time utility x 100

Loom efficiency = —————————————-

…………………………………..Shift time

…7.583 x 100

= ———————–

………..8

= 94.78% **(Ans)**

……………………………….Loom RPM x 60 x Shift time x Efficiency

Loom Production = ———————————————————————

…………………………………………….PPI x 39.37 x 100

…700 x 60 x 8 x 94.78

= ———————————– meters

……90 x 39.37 x 100

= 89.87 meters **(Ans)**

**Conclusion**

I have tried to explain/show all the calculations of Loom or Fabric Production in **weaving mill** with so many examples through this article. Hope this article will be helpful for those who are new to the Weaving mill or those who are students.

**Author of this Article:**

Md. Imran Hossain

B.Sc. in Textile Engineering

Shahid Abdur Rab Serniabat Textile Engineering College, Barisal.

Email: mdimranhossain.te@gmail.com

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Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. He is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.