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

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

Md. Abu Sayed
Founder of Textile Apex
Pabna Textile engineering college, Pabna, Bangladesh
Email: sayed1952@facebook.com
Cell : +8801745214773

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. To complete finished products (yarn) in spinning every spinner must know some formulas. In this article I will discuss about some formula of blow room, carding and drawframe. I will give some examples of spinning calculation also.
 Essential formula for Spinning
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  …………………………
36 X 840 X Sliver hank
X Efficiency% X Waste%

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

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 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 machine in carding section. Each carding machine needs a lap for every 3.5 hr. The carding section operates for 24 hrs at efficiency 85%. If the blow room needs 5.5 min to produce a lap of 40 yd, then how long the blow room section should be kept running?

Given (in carding section),
• No. of carding machine = 36
• 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
Time required = ……….. X 210 = 19.25 hrs. (ANS)
60

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