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Prime School BD (PSBD24) is popular blog site about technology, merchandising, textile & accounting rules in Bangladesh. Also the post that are publishing about Accounting tutorial, Textile, RMG, Merchandising, Knit Merchandising, Woven Merchandising, Apparel Merchandising, Garments, Dyeing, Spinning, Washing, Buying House, else many things with tips & tricks. বদিউজ্জামান ( রুবেল )
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Production Calculation of Knitting

Knitting Production calculation shortcut Formula:

(0.00, 00,005934 × Number of Needle × Number of Feeder × Stitch Length × RPM × 60) ÷ Yarn count. = Production (kg)

Suppose Example:

Number of Needle = 2400
Number of Feeder = 96
Stitch Length = 2.85"
Cylinder RPM = 26
Time = 60 Minute
Yarn count = 26/1

(0.0000005934 × 2400 × 96 × 2.85 × 26 × 60) ÷ 26 = 23.38 kg
===============================================================================

Knitting Calculation: 
Production calculation of knitting means calculation of knitting machine production. To calculate knitting machine production by weighing the total production of one hour or one shift or one day.


Production Calculation for Knitting
Knitting machine
The practical way calculating production of a machine is as follows. In this method following information for production calculation are required: 
·         Machine Guage and Dia
·         RPM of Knitting Machine
·         Yarn Count
·         Stitch Length
==============================================================================
Knitting Calculation Formula:
Some important formula of knitting production calculation have mentioned in the below:

1. Production in length,
= Course per minute/ Course per inch,

Or,
= CPM/CPI

Or,
    Number of feeder × cylinder RPM × Time × Efficiency / CPI / 36

2. Course per inch,
= Course per minute / production in length

3. Course per minute,
= Course per inch × Production in length

4. Stitch density,
= Course per cm / Wales per cm

5. Fabric width,
= {(∏× diameter of cylinder × machine gauge) / wales per cm}

Or,
= Number of wales / Wales per cm

Or,
= Number of needle / wales per cm

6. Fabric weight,
= {(Course per minute × yarn length per course) / yarn count}

7. Needle number of machine,
= ∏ × diameter of cylinder × gauge

8. Yarn length per course,
= Total number of machine × loop length

9. Production of single jersey machine in weight (kg) per hour,
∏ × cylinder dia (inch) × Cylinder RPM × feeder no. × Gauge × stitch length (mm) × tex × 60 × efficiency / 1000 / 1000 / 1000

10. Production of double jersey in length,
= Single jersey production in length/2

11. Production of double jersey in weight,
= Single jersey ×2

Production Calculation of Knitting Machine in Textile:
Example-01:
If machine diameter= 20 inch, feeder number= 90, course per cm= 15, machine speed= 25 RPM and machine efficiency is 90% then calculate the production per shift of a single jersey circular knitting machine.

Solution:
Here,
Diameter of machine= 20 inch,
Number of feeder= 90,
Machine speed or machine cylinder RPM= 25 RPM,
Machine efficiency= 90%= 0.9,
Time= 1 shift= 8 hours = (8×60) =480 minute
Course per cm= 15,
Course per inch (CPI) = (15/0.3937) = 38.10≈38 

So,
Production in meter per shift,
 = No. of feeder × cylinder RPM × time × efficiency / CPI / 36
= 90 × 25 × 480 × 0.9 / 38 / 36
= 710.53 yds.
= (710.53×0.9144) m
= 649.7 m per shift 

So, production per shift for single jersey circular knitting machine is 649.7m

Example-02:
Calculate the length in meter of a plain single jersey fabric at 16 courses per centimeter on a 26 inch diameter and 28 gauge machine having 100 feeders. The knitting machine operates for 8 hours at 29 RPM at efficiency of 90%.

Solution:
Given that,
Machine dia = 26 inch,
Machine gauge = 28,
Number of feeder = 100,
Machine speed or cylinder RPM = 29 RPM,
Efficiency = 90% = 0.9,
Time= 8 hours = (8 × 60) = 480 minute,
Course per centimeter = 16,
Course per inch (CPI) = 16/0.3937 = 40.64 ≈ 41

So,
Production in meter per shift,
= Number of feeder× machine speed× time× efficiency / CPI / 36
= 100 × 29 × 480 × 0.9 / 41 / 36
= 848.78 meter per 8 hours,
= (848.78 × 0.9144) m
= 776.12 m per 8 hours

So, production for this calculation stands at 776.12m per 8 hours.

===============================================================================

Example 01:  
Find out the production per shift for single jersey and rib from the following data: 

For single jersey, 
Fabric width = 53 ", GSM = 150, Yarn count (Ne) = 26S 
Stitch length = 2.85 mm, Cylinder Dia(D) = 25", Cylinder Gauge(G) = 24 
No. of feeder = 75, R.P.M of cyl.= 25, Time =8 hrs, Effi.= 80% 

Solution:
Production/8hrs, 

    πDG X S.L (mm) X No. of feeder X RPM X 60 X 8 X Efficiency 
……………………………………………………………………………… kg 
                       2.54 X 36 X 840 X 26 X 2.2046 

    3.1416 X 25 X 24 X 75 X 25 X 60 X 0.80 
………………………………………………………………………………kg 
           2.54 X 36 X 840 X 26 X 2.2046 

= 87.85 kg (Ans)


For Rib, 
Fabric width = 41", GSM = 460 , Yarn count,Ne = 24S 
Stitch length = 2.90 mm, Cylinder dia,D= 32", Cylinder Gauge,G= 18 
No. of feeder = 62, R.P.M.of cyl.= 15, Time =8 hrs, Effi.= 80% 

Production/8hrs, 

   πDG X S.L (mm) X No. of feeder X RPM X 60 X 8 X Efficiency X Feeder/course (kg) 
……………………………………………………………………………................………… 
                                      2.54 X 36 X 840 X Ne X 2.2046 


   3.1416 X 32 X 18 X 2.90 X 62 X 15 X 60 X 8 X 0.80 
………………………………………………………………….. X 2 kg 
               2.54 X 36 X 840 X Ne X 2.2046 

= 92.22 kg (Ans)


Example 02:
Calculate nominal production of a single jersey-knitting machine per hour from the data given: 
·         Machine Gauge = 24
·         Machine Dia = 30 inches
·         Number of Feeders = 90
·         Machine RPM = 26
·         Yarn Count = 24
·         Stitch length = 4 mm
·         Efficiency = 85%

Solution: 

Step one 
First we will calculate number of needles and number of stitches produced in one revolution. This would help us in calculating the total length of yarn consumed in one revolution. 

Number of needles = Machine dia X Gauge X p (3.14) 

= 30 X 24 X 3.14 

= 2260 (Exact 2260.8 but needles are always in even number so we will take nearest even figure) 

Number of stitches produced in revolution 
Every needle is making one stitch on every feeder because machine is producing single jersey fabric (full knit fabric). 

Number of stitches produced in one revolution = Number of needles X Number of feeders 

= 2260 X 90 

= 203400 

This machine is making 203400 stitches in one revolution. 

Step Two 

Length of stitch is 04 mm (stitch length is always calculated in metric system) 

From this we can calculate yarn consumption in yards in one hour 

Yarn Consumption (in yards) in one hour, 

   Number of stitches X length of (mm) X RPM X60 (minutes) 
…………………………………………………………….. 
                   1000(to convert mm into meters) 

    203400 X 4 X 26 X 60 
………………………………………
                  1000 

= 1269216 meters or 

= 1388015 yards 

Step Three 
In previous step we calculated quantity of yarn consumed in yards. We can easily calculate weight of this yarn while its count is known (see example 03). 

Weight of cotton yarn, 

   Length of yarn 
…………………….. 
   Count X 840 

    1388015 
………………….. 
   Count X 840 

= 68.85 pounds or 

= 31.23 Kilo grams 

Efficiency 85% = 26.55 Kilo grams 

Answer: This machine can produce 26.55 Kgs fabric in one hour at 85 % efficiency


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