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Waste Calculation in Blow Room

Waste Calculation in Blow Room
Mustaque Ahammed
Quality Assurance Officer,
Lamisa Spinning Ltd. Tongi, Gazipur
Cell: +8801723300703
Email: mamuntex09@gmail.com



Cotton contains huge amount of dusts, foreign matters, seed and other particles. During spinning of cotton yarn some wastes produce at different stages. We can classify in three categories. They are follows:
  1. Directly reusable waste;
  2. Dirty waste; and
  3. Dust and fly.
In this article we will calculate blow room waste. Before calculating blowroom waste we have to know which are blow room waste. Dropping-II, Dust, filter waste are the blow room waste. Normally, fibers represent about 40 - 60% of blow room waste. In order to clean, it is necessary to eliminate about as much fibers as foreign material.
Blow room waste (dropping)
Blow room waste (dropping)
Waste removed from blow room is very important regarding cleaning efficiency of blow room.

Waste = lint + trash
Input = output x (100/100 – Waste%)
Output = input – waste
Waste% = waste x 100/input
Cleaning efficiency = waste extracted x 100/total waste

Some examples are given below for clear concept:
 

Question1: 
80 bales of cotton each of 167 kg, are being fed daily in a 2-scutcher blow room line. Actual production per 2-scutcher per day is 12000kg. Calculate the total quantity of waste throughout whole blow room line & waste %age.

Solution:

Input = 80 x 167 = 13360 kg
Output = 12000 kg
Waste = 13360 – 12000 = 1360 kg
Waste% = 1360 x 100/13360 = 10.18%
(ANS)

Question2: 

Production per hour from scutcher of 3-scutcher blow room line is 310 lbs. waste %age of blow room is 6.5%. Calculate the no. of bales to be fed in given blow room per month provided that one bale is os 168 kg.

Solution:


Blow room output per day = 310 x 3 x 24/2.2046 = 10124.7 kg

                   Input – Output
Waste% = ……………………… x 100%
                         Input

               Input – 10124.7
=> 6.5 = …………………........ x 100%
                      Input

=> (100 – 6.5) input = 1012474.5 kg

Input = 1012474.5/93.5 = 10828.6 kg/day

Hence no. of bales fed per month
= 10828.6 x 30/168
= 1934 bales
(ANS)

Question3: 

The production per scutcher per hour in a 2-scutcher blow room line is 325 lbs. waste from whole blowroom line is 700 kg/day. Calculate the no of bales required per day for given blow room line. (1 bale = 167 kg).

Solution:


Waste = 700 kg
Output = 325 x 2 x 24/2.2046 = 7076.4 kg/day
Input = 7076.4 + 700 = 7776.4 kg/day
No of bales/day fed = 7776.4/167 = 47 bales (ANS)

Question4: 

63 bales of cotton are being fed daily in a blow room line consisting of 2-scutchers. The blow room is to be kept stopped for one hour after each shift for maintenance. If waste %age is 6.5%, what will be the production per scutcher in kg/hour, while 1 bale = 166kg.

Solution:

Input = 63 x 166 = 10458 kg/day
Waste = 10458 x 6.5/100 = 679.77 kg

Output = 10458 – 679.77
= 9778.23 kg/day

Prod. Per scutcher per day = 9778.23/2x21
= 232.82 kg/hour
(ANS)

Question5: 

80 bales of cotton are being fed in a blow room line daily. If the pure weight of cotton per bale is 168 kg and waste% of blow room line is 6%.
  • What will be the wt. of cotton lap received per day from scutcher.
  • Calculate the no. of laps prepared per day if the wt. of one lap is 22kg.
  • If lap rod is 2kg then calculate no. of pure lint laps.
Solution:

Input = 80 x 168 = 13440kg
Waste = 6%

Waste = 13440 x 6/100
= 806.4 kg

Output = 13440 – 806.4
= 12633.6 kg/day

This is cotton lap received per day

No of laps/day = 12633.6/22
= 574.2 laps

Pure lint laps/day = 12633.6/20
= 631.68 laps
(ANS)

Question6: 

A lap of 50 lbs with a length of 55yds is being prepared on scutcher in 4.5 min. if the waste %age of blow room line 7%, what should be required no. of bales to be fed daily, if bale wt = 170kg

Solution:

50 lbs are prepared in = 4.5 min

In one hour = 50 x 60/4.5
= 666.67 lbs

Production per day = 666.67 x 24
= 16000 lbs/day

Hence,
Input = 16000 (100/93) = 17204.3 lbs/day

No of bales = 17204.3/2.2046x170
= 46 bales
(ANS)

Question7: 

The total material fed into a step cleaner was 800 lbs/hr. The cleaning efficiency of machine was found to be 35%. The total material delivered per hour was found to be 2% less than the fed material. Calculate total quantity of waste as well as trash per hour. If there is 80% trash of total waste.

Solution:

Input = 800 lbs/hr
Output = 800 (1 - 0.002) = 784 lbs/hr
Waste = 800 – 784 = 16 lbs
Waste% = 16 x 100/800 = 2%
Trash% = 80% of waste
Trash = 16 x 80/100
= 12.8 lbs
(ANS)

Production Calculation of Speed Frame or Simplex

Production Calculation of Speed Frame or Simplex
Rofiquzzaman Raju
Fabric Technologist,
B.J.Group, Mawna, Gazipur
Chittagong Textile Engineering College
Facebook: https://www.facebook.com/ERZRAZU




Speed Frame:
Speed Frame or Simplex is an important process in ring spinning. In this process fibers are converted into low twist lea called roving. So it is also called roving frame. The main function of roving frame is the attenuation of sliver. To draft the sliver to reduce weight per unit length. The sliver which is taken from draw frame is thicker so it is not suitable for manufacturing of yarn. By speed frame sliver are converted to roving. Which is appropriate for next process. Speed frame is used to the carded and combed yarn process but for the rotor spinning system this process can be eliminated.
Speed Frame

Simplex Production Calculation:
Problem: 1
Calculate the TPI (twist per inch) produced on a simplex with diameter of front roller 28 mm and its rpm be 30. The rpm of flyer is 1000.

Solution:

Here,

Dia of front roller = 28 mm = 2.8 cm = 1.1024 inch
rpm of front roller = 30
rpm of flyer = 1000
TPI = ?

We know,

Surface speed of front roller = π x Dia of front roller x rpm of front roller
= π x 1.1024 x 30
= 103.9 inch/min

                        Flyer speed or Spindle speed (rpm)
Twist or TPI = ………………......……………………
                             Delivery speed (inches/min)

    1000
= ……………
   103.9

= 9.63 (Ans)

Problem: 2
Calculate the TPI on simplex if the diameter of back roller is 15/16’’, rpm of B.R is 10, rpm of flyer is 1000 and draft is 6.

Solution:

Here,

Dia of B.R. = 15/16 = 0.9375 inch
Draft = 6
rpm of F.R. = 30
rpm of B.R = 10
rpm of flyer = 1000
TPI = ?

We know,

Surface speed of B.R. = π x Dia of B.R. x rpm of B.R
= π x 0.9375 x 10
= 29.45 inch/min

                      Surface speed of F.R.
Total draft = ………………………….
                     Surface speed of B.R.

=> Surface speed of F.R.= 6 x 29.45 = 176.7 inch/min

                        Flyer speed or Spindle speed (rpm)
Twist or TPI = …………………......……………….
                            Delivery speed (inches/min)

   1000
= …………
   176.7

= 5.66 (Ans)

Problem: 3
If Spindle speed = 1600 rpm, Roving count = 90 Ne, TM (Twist Multiplier) = 4.2, Efficiency = 85% then calculate the production of a speed frame in lb/hr.

Solution:

We know,

                      Spindle speed
Production = ……………..
                             TPI

TPI = TM√(Roving count)

Efficiency = 85% = 85/100 = 0.85

Now,

                     Spindle speed
Production = ……………..
                            TPI

   1600 x 60 x 1 x 0.85 x 120
= ……………………………………….
   4.2√.90 x 36 x 840 x 0.90

= 90.297 (Ans)


How to Select Yarn Count for Specific Fabric GSM

How to Select Yarn Count for Specific Fabric GSM
Rofiquzzaman Raju
Fabric Technologist,
B.J.Group, Mawna, Gazipur
Chittagong Textile Engineering College
Facebook: https://www.facebook.com/ERZRAZU



Yarn Count:
Yarn count is very useful to know the condition of yarn. I mean, yarn is thick or thin. So we can define count in the following way,

The yarn count is a numerical expression which indicates the coarseness or fineness of a yarn.

Fabric GSM:
GSM means Grams per Square Meter. Fabric GSM means weight of one square meter fabric in grams. GSM plays an important role in textile industry. It is widely used in case of knit fabric measurement. By this we can compare the fabrics in unit area which is heavier and which is lighter.

How do Select the Correct Yarn Count for Your Specific Fabric GSM?
How to select yarn count for specific fabric GSM is a very common and technical task for textile engineers. By the using following formula you can easily select the actual yarn count for knit the fabric. These are varying for fabric types.

Single Jersey:
Say, the require GSM is 160

Yarn count = (-0.141) X (GSM) + 50.22
= (-0.141) X (160) + 50.22
= -22.58 + 50.22
= 27.66

So, to knit 160 gsm single jersey fabric we need yarn count 27.66/s

Interlock:
Say, the require GSM is 220

Yarn count = (-0.206) X (GSM) + 80.56
= (-0.206) X (220) + 80.56
= -45.32 + 80.56
= 35.24

So, to knit 220 GSM Interlock fabrics we need yarn count 36/s

Pique:
Say, the require GSM is 220

Yarn count = (-0.146) X (GSM) + 57.16
= (-0.146) X (220) + 57.16
= -32.12 + 57.16
= 25.04

So, to knit 220 GSM Pique fabric we need yarn count 36/s

1*1 Rib:
Say, the require GSM is 220

Yarn count = (-0.123) X (GSM) + 54.57
= (-0.123) X (220) + 54.57
= -27.06 + 54.57
= 27.51

So, to knit 220 GSM 1x1 Rib fabrics we need yarn count 28/s

Double Lacoste:
Say, the require GSM is 220

Yarn count = (-0.167) X (GSM) + 64.36
= (-0.167) X (220) + 64.36
= -36.74 + 64.36
= 27.62

So, to knit 220 GSM Double Lacoste fabrics we need yarn count 28/s

Lycra 1×1 Rib:
Let, required fabric GSM is 180

Yarn Count = (-0.119) GSM + 59.12
= (-0.119) x 180 + 59.12
= -21.42 + 59.12
=37.7

Lycra 2x2 Rib:
Say, the require GSM is 220

Yarn count = (-0.108) X (GSM) + 56.62
= (-0.108) X (220) + 56.62
= -23.76 + 56.62
= 32.86

So, to knit 220 GSM Lycra 2x2 Rib fabrics we need yarn count 32/s


How to Find Out Sewing Time with Machine RPM

How to Find Out Sewing Time with Machine RPM
Noor Ahmed Raaz
B.Sc. in Textile Engineering (CU)
Specialized in Apparel Manufacturing
Merchandiser
A.M.C.S Textile Ltd (AEPZ)
Email: raju.uttara105@gmail.com



Introduction:
Calculation of sewing time is an important task for industrial engineers. Because it will be effective to get actual time to be taken by a sewing operator to sew a specific length of seam. From this we can get an operator production efficiency easily. If you read article with concentrately then I think you easily calculate sewing time.
Sewing by an operator
Sewing by an operator
Estimation of Sewing Time Using Machine RPM:
Machine RPM means Revolution Per Minute of that machine. By machine RPM we can get time to sew a specific length of seam with specific Stitch per Inch (SPI). Before calculating garments sewing time by using machine RPM, an industrial engineer should confirm about the below points: 

  • Stitch per inch (SPI) of the garments,
  • Seam length in inch of the garments,
  • Sewing machine RPM (Revolution per minute).
Now by using the below formula, an industrial engineer can easily calculate the required garments sewing time from machine RPM.

Machine cycle time or sewing time (in second),

   Stitch per inch (SPI) x Seam length in inch x 60
= ……………………………………………………………
                 Sewing Machine RPM

If we see an example then concept will be clear,
Example:
If a plain stitch sewing machine RPM is 1400. How much time needed to sew a 40 inch length seam, where stitch per inch (SPI) is 8?

Solution:

Here,

Sewing machine RPM= 1400,
Seam length in inch= 50”,
Stitch per inch (SPI) = 8.

We know that,

Machine cycle time or sewing time (in second),

   Stitch per inch (SPI) x Seam length in inch x 60
= ………………………………………………………
                  Sewing Machine RPM

   8 x 50 x 60
= …………………
       1400

   24000
= …………
   1400

= 17.14 sec

So. Sewing time of that machine is 17.14 sec.


Poly Bag Consumption in Garments Industry

Poly Bag Consumption in Garments Industry
Mayedul Islam
Merchandiser at Fashion Xpress Buying House.
Badda, Dhaka, Bangladesh.
Email: mayedul.islam66@gmail.com


Introduction:
Poly bags, commonly known as polythene bags, have a variety of uses in many industries. But it has great use in garments industry. It is used to contain garments destined for export or to merchandise so that apparels remain intact and they could not obtain dust, dirt or moisture. Poly bag consumption is an important matter in apparel merchandising. Because it also keeps effect on total pricing of order. In previous article we have discussed on costing of poly bag for merchandisers.
Poly bag in garment industry
Consumption of Poly Bag:
For consumption of poly bag, apparel merchandiser should know the following information.
  1. Poly bag length in inch
  2. Poly bag width in inch
  3. Thickness of poly bag in gauge,
  4. ½ flap of poly bag
  5. Print on the poly bag
Using formula, we can easily calculate the poly bag consumption in garment industry.

Poly bag consumption (for 1000pcs in kg),

   (Poly bag length + ½ Flap) x Poly bag width x Thickness of poly bag
= ……………………………….…………………………………………..……
                                                    3300

Note: 3300 is a constant number for 1000 pcs

For clearing this formula, I’m giving an example. I think it will be helpful to understand this formula.

Example:
Suppose, for a garments export order (100,000pcs), the buyer “GAP” suggests the below information about the poly bag.

Length of poly bag- 40”,
Poly bag width- 30”,
Thickness of poly bag- 170 gauge,
½ flap of poly bag- 3”,

Now you have to calculate the poly bag consumption for the above order.

Solution:

Poly bag consumption (for 1000pcs in kg),

   (Poly bag length + ½ Flap) x Poly bag width x Thickness of poly bag
= ……………………………….……………………………………………………
                                                 3300

   (40 + 3) x 30 x 170
= ……………………………
             3300

   43 x 30 x 170
= ………………….
        3300

   219300
= ……………
    3300

= 66.45

66.45 kg per 1000pcs poly bag.

So, for 1000pcs poly bag, LDPE polymer needed 66.45kg.

For 100,000pcs poly bag, LDPE polymer needed = (66.45 × 100) = 6645kg.


Fabric Consumption for Basic T-shirt

Fabric Consumption for Basic T-shirt
Mayedul Islam
Merchandiser at Fashion Xpress Buying House.
Badda, Dhaka, Bangladesh.
Email: mayedul.islam66@gmail.com



Introduction:
Fabric consumption is an important task for garments merchandiser. Because 50% cost for garments making is fabric. If fabric consumption and calculation is not correct then company will face to huge loss. There are two formula or process of fabric consumption for basic t-shirt. One in Centimeter and another in Inch. They are given below.

Sketch of t-shirt
Calculation – 01: Formula in Centimeter:
Suppose one of T-shirt’s Body length (72+4) cm, Slib length (23+2) cm, Chest length (Dia) (53+2) cm and G.S.M 180. Determine the fabric consumption for the basic T-Shirt.

Solution:

Here, Body Length = 76 cm
Sleeve Length = 25 cm
Chest Length = 55×2=110 cm (For both side)

We get,

                                   (Body length + Sleeve length) x (Chest x 2) x G.S.Μ
Fabric consumption = ……………………………………………......………….. Kg
                                                                  1000 x 10000

   (76 + 25) x (55x2) x 180
= …………………………………
          1000 x 10000

    101 x 19800
= …………………
      10000000

   1999800
= ………………….
   10000000

= 0.19998 kg

The amount of fabric is just for 1 piece. Generally 12 pieces are counted with one.

Fabric consumption for 1 Dozen = 12×0.19998 kgs
= 2.399 kgs

Fabric consumption for 1 Dozen 2 kgs and 399 gms.

Calculation – 02: Formula in Inch:
Here, Body Length = (28+ 1) inch
Sleeve Length = (9+1) inch

Chest Length = (21+1) inch =22 inch×2
= 44 inch

G.S.M = 180

According to formula,

                                   (Body length + Sleeve length) x (Chest x 2) x G.S.Μ
Fabric consumption = ……………………………………………….........……….. Kg
                                                                 1550 x 1000

  (29 + 10) x (22x2) x 180
= …………………………………..
        1550 x 1000

    308880
= ………………….
   1550000

= 0.199920 kgs

The amount of fabric is just for 1 piece. Generally 12 pieces are counted with one.

Fabric consumption for 1 Dozen = 12×0.199920 kg
= 2.391 kg

Fabric consumption for 1 Dozen 2 kg and 391 gm.