# Useful Formulas for Spinning (Blow room, Carding and Draw frame)

What is Spinning?
Spinning is a major and ancient part of the textile industry. It is part of the textile manufacturing process where three types of fiber are converted into yarn, then fabrics, which undergo finishing processes such as bleaching to become textiles. The spinning process involves pulling, twisting, and winding fibers together to create a continuous strand of yarn. To complete finished products (yarn) in spinning every spinner must know some formulas. In this article I will discuss some formula of blow room, carding, and draw frame. I will give some examples of spinning calculation also. Useful formulas for Spinning is as follows:

### Some Useful Formulas for Spinning (Blow room, Carding and Draw frame)

The essential formula for Spinning:

……  Lap length in yard            … …wt. unit i.e. lb
1. Lap hank = …………………………………  X  ………………………………
…………………..Length unit i.e. 840 yd          ……wt. of lap in lb

……………………………………Sliver length in yd (L)          ….. .1 lb (w)
2. Carded sliver hank = …………………………………..  X  ………………………
……………………………………..840 yd (l) Sliver                  wt. in lb (W)

……………………………..Delivery or Carded sliver hank
3. Actual draft = ………………………………………………………
………………………………………Feed or lap hank

…………….Feed or lap wt.
= ……………………………………………….
……Delivery or carded sliver wt.

…………………………………………100
= Mechanical draft  X  ………………………..
……………………………………100 – Waste

…………………………….…………………………….………………..100 – Waste
4. Mechanical or technological draft = Actual draft X ……………………
……………………………..……………………………………..……………..100

………..Draft constant
= …………………………………..
………..……. .Draft

……………………………..………………………… Present hank
5. Required DCP = Present DCP  X  ………………………………..
……………………………….………………………..Required hank

………………………………Required sliver wt.
= Present DCP X ………………………………………
………………………………..Present sliver wt.

……………………………………..……………………………………..……. … ..60
6. Production in lb/hr = Surface speed of doffer X  …………………………………  X Efficiency% X Waste%
……………………………………..………………………………36 X 840 X Sliver hank

……………………………………..……………..……………. … 60
Or, Surface speed of calendar roller X …………………………………….  X Tension draft X Efficiency% X Waste%
……………………………………..………………36 X 840 X Hank of sliver

Problems:

1. Find out the carded sliver hank if lap wt. is 14 oz/yd, draft is 100 and waste is 4%.

Given,

• Lap wt. = 14oz/yd
• Draft = 100
• Waste = 4%
• Carded sliver hank =?

………………………………………….L     ..        w (1 oz =1/16 lb) u
Lap or feed material hank = …….. X ……………………………………
…………………………………………..Lu                      … W

…..1 yd                  16 oz
= ……………. X …………….
…..840 yd              14 oz

= 0.00136

…………………………………………………….…… ..100
Actual draft = Mechanical draft X ……………………………
………………………………………………………100 – Waste

…………………. .100
= 100 X ……………………
……………..100 – Waste

= 104.16667

So, the delivery carded sliver hank = Feed hank X Actual draft

= 0.00136 X 104.16667
= 0.14167 (Ans)

2. A carding m/c produces 0.17 hank sliver from 13 oz/yd lap by generating 6% waste. What will be the mechanical draft?

Given,

• Lap wet = 13 oz/yd
• Length = 1 yd
• Waste = 6%
• Carded sliver hank = 0.17
• Mechanical draft =?

1                  16
Feed hank = …………… X …………….
…..…..…..………840                  13

= 0.00146

……………………..Delivery hank                  0.17
Actual draft = ………………………….. = …………………… = 0.116.44
………………………..Feed hank                      0.0014

……………………………………………………. 100 – Waste                      100 – 6
Mechanical draft = Actual draft X …………………………. = 116.44 X ………………..
………………………………………………..………. 100                                 100

= 109.45 (ANS)

3. Find out the production of a carding machine for 1 day in a metric ton from the following data –
• Doffer speed = 15 rpm
• Doffer dia = 85”
• Wt. of delivered sliver = 65 grain/yd
• Machine efficiency = 85%
• 1 metric ton = 2204 lb
We get,

……………………………………………  1                    1
Production in metric ton/day = πdn X 60 X 24 X 65 X ………… X ………………..
………………………………………………………………………………..7000             2204
….…..1                 85
X ………… X …………… = 0.573495 (ANS)
……..36               100

4. In a spinning mill there are 36 carding machines in carding section. Each carding machine needs a lap for every 3.5 hr. The carding section operates for 24 hrs at an efficiency 85%. If the blow room needs 5.5 min to produce a lap of 40 yds, then how long the blow room section should be kept running?

Given (in carding section),

• No. of carding machine = 36
• The efficiency of the carding machine = 85%
• Running time = 24 hrs
• Lap needed at every 3.5 hrs
• Blow room section,
• Lap length = 40 yd
• Time to produce a lap = 5.5 min
• Running time of blow room =?

………………………………  ..85          1
No. of lap = 36 X 24 X ……… X …………. = 209.829   ͌   210
…………………………………100           3.5

…………………………….5.5
The time required = ……….. X 210 = 19.25 hrs. (ANS)
……………………………….60

```Author this Article:
Md. Abu Sayed
Founder of Textile Apex
Pabna Textile engineering college, Pabna, Bangladesh
Email: [email protected]
Cell : +8801745214773```

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