Production and Gearing Calculations of a Comber Machine

Introduction:
Combing is a method for preparing carded fiber for spinning. Combing allows the production of very fine, high-quality spun yarns. Combing process is operated by comber machine. In the combing preparation, several card slivers are drawn and wound up parallel as comber rolls on a sliver lap machine. It is an intermittent operation carried out between carding and draw frame. The combing process aims to remove short fibers from the group of fibers. The sliver produced in the carding process has poor fiber orientation and higher short-fiber content. The main objective of combing process is to remove short fibers and to improve fiber orientation. Combing is a key process that makes the difference between an ordinary yarn and a quality yarn. In this article I will discuss purpose of combing, technical data of modern comber machine, gearing plan and production calculation of comber machine.

Purpose of combing:
The purpose of combing is removing the short fibers (fibers having length lesser than a specified minimum) in the sliver and improving the mean length, removing the neps and sticky trash along with the short fibers and converting the combed cotton into a sliver form, coiling and delivering it in cans for next process.

Methods of improving the noil percentage:

1. By changing the type of feed. Backward feed will obviously result in increasing no percentage because during backward feed of fibers combing is done 4 times where as it is 3 times in case of forward feed.
2. By changing the ratchet wheel number i.e. decreasing the ratchet wheel teeth amount of noil % can be increased.
3. By changing the distance between nipper to detaching or by changing the index. If the index is more, then the % of noils removed will also be more.
4. By decreasing the distance between top comb and unicomb the percentage removal of noil is increased.

Technical specifications of a modern comber machine:

• No. of combing heads ————-8
• Maximum mechanical speed —–400 nips/min
• Maximum attainable speed ——–350 nips/min
• Delivery count ———————-0.10 to 0.18 (Ne)
• Lap dimension ———————-267–305 mm width
• Weight – max. ———————-80 g/m
• Actual feed rate per nip ————3.76 to 5.91 mm
• Type of feeding ———————Counter feed – standard
• Forward feed ————————Optional
• Maximum lap diameter ————-600 mm
• Noil percentage ———————5–25%
• Doubling —————————-2 × 4 fold
• Main motor ————————–4 to 4.86 kW
• Brush motor ————————–1.5 kW
• Can size diameter ——————–400–450–500 mm
• Height ———————————1050 mm (42 in.)

Production calculation formula of comber machine:

…………………………………50% span length of comber sliver – lap               100
Combing efficiency = ————————————————————— x —————-
………………………………………………………Comber lap C                                     C

where C is the noil %

…………………………………….Short fibers in the lap (%) – Short fibers in the sliver (%)
Short fiber removal (%) = ——————————————————————————– x 100
…………………………………………………………Short fibers in the lap (%)

…………………………………  ……..Mean length of sliver (mm) – Mean length in lap (mm)
Improvement in mean length (%) =—————————————————————— x 100
…………………………………………………………….. Mean length in the lap (mm)

………………………………..Neps per gram in the lap – Neps per gram in the sliver
Nep removal (%) = ————————————————————————————— x 100
…………………………………………………….Neps per gram in the lap

Gearing diagram of a comber:

You may also like: Gearing Diagram, Draft and Draft Constant of Comber Machine

Gearing calculations of a comber machine:

Speed calculations:

…………………………………………………………..3.8        16
(i) Speed of brush roller = 2850 × ———– x ———– = 960 rpm
…………………………………………………………..9.5        19

……………………………………………………………………6.5      29
(ii) Speed of combing cylinder = 1430 × ——— x ———
……………………………………………………………………5.5     143

………………………………………………………………………6.5          29        32          5         40
(iii) Speed of table calender roller =1430 × ——– x ——– x ——– x ——– x ——–
……………………………………………………………………….8.5         143       32         29        48

= 31.863 rpm

(iv) Speed of third roller = 1430 × 143 = 84.9312 rpm

Waste:

• The variation in comber waste between combers = ± 0.5%
• The variation in comber waste within a comber = ±1.5%

References:

1. Mechanics and Calculations of Textile Machinery by B. Varadarajan, C. B. Senthil Kumar, and N Gokarneshan
2. Process Management in Spinning by R. Senthil Kumar
3. Handbook on Cotton Spinning Industry by B. Purushothama
4. Textile Technology – An Introduction, 2nd Edition by Thomas Gries, Dieter Veit and Burkhard Wulfhorst

You may also like:

1. Combing Cycle of Comber Machine in Cotton Spinning
2. Working Principle of Combing Operation
3. Comber Machine: Types, Combing Process and Basic Elements
4. Problems / Defects / Faults of Combing Process with Causes and Remedies
5. Combing Process of Cotton with Control and Check Points
6. Process of Controlling Waste in Comber

Mazharul Islam Kiron

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

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