SlideShare ist ein Scribd-Unternehmen logo
1 von 11
Downloaden Sie, um offline zu lesen
THE COMBING PROCESS
Introduction
The process of straightening and parallelizing of fibers and
the removal of short fibers and impurities by using a comb on
combs assisted by brushes and rollers is called combing.
 The combing process is carried out in order to improve the
quality of the sliver coming out of the card. The process
eliminates short fibers, it achieves better parallelization of
fibers, it straightens curls, and it removes neps and residue
impurities.
Objectives (tasks)of Combing
Following are the objectives of combing process:
 To remove naps in the carded sliver.
 To make the fiber more parallel and straight.
 To produce a uniform sliver of required per length.
 To remove the fiber shorter than a predetermine length.
 To remove remaining impurities in the comber lap.
Necessity of Combing
The following quality of fibers can only be obtained by
combing
 Absence of nap
 More parallel arrangement of fibers
 Straight fibers
 Clean finer fiber
 Uniformity in length of fiber
FACTOR INFLUENCING THE COMBING PROCESS
1. Machine settings
I. Feed distance:- This indicates the distance fed by the
feed roller per cycle; high feed distance increases the
production rate but, reduces the comber noil and
deteriorates the quality. However, % noil and feed rate
relationship is different for forward and backward feed
systems Feed distance also very much depends upon the
staple length. Fig Cm-5 indicates typical values of feed
distance for different length of cotton fiber.
Cont..
II. Feed type:- Feeding can take place when the
nippers move backwards (known as backward feed
or counter-feed) and alternatively, when nippers
move forward (known as forward feed or
concurrent feed) during a combing cycle. Counter-
feed is used when better quality of product is
required at the loss of more noil (12-25%).
Concurrent feed is preferred when higher
production rate with less noil desired (5-12%).
Cont…
III. Detachment setting:- This is one of the main settings
responsible for the change of noil percentage. This
setting refers to the distance between the bite of the
nippers and the nip of the detaching rollers when nipper
assembly is at the most advance position. A closer setting
is associated with lower noil level. Detachment setting
normally lies in the range of 15-25 mm. A large setting
(more than optimum) does not produce further
improvement in quality, but results in more loss of noil.
As such, optimum setting has to be found out depending
on quality and production level desired for a particular
machine and material processed.
Cont…
IV. Number of point on comb;
Saw tooth clothing is used in circular comb and needles are
used in top comb. Fineness and point density depend on
the raw material processed. Usually top comb point
density falls in the range 23-32 needles per centimeter.
More needles give more noils.
V. Depth of penetration of top comb:-
Lowering of the top comb by about 0.5 mm is followed by an
increase in noil of about 2%. The main improvement is
seen in elimination of neps. Over deep penetration of the
top comb disturbs fiber movement during piecing and so
optimum penetration is very important.
Cont…
VI. Piecing and detachment timing:-
During piecing, fiber fringes are laid on top of each other in
the same way as roofing tiles. Sliver produced in this way
has a wave like structure due to this piecing having a
wavelength of 30-75 cm. This is known as piecing defect.
• The combed fiber fringes can be compared with very flat
parallelogram although the leading edge is blunter. By using
correct setting (by adjusting the timing when detaching
begins relative to the instant at which the fringe protruding
from the nipper reaches the nip line of the detaching
rollers), it is possible to lay the fringes on each other in
such a way that unevenness in successive fringes partly
cancels out. On the other hand, incorrect settings will
cause an increase in unevenness arising from piecing.
2.Properties of raw material
I. Fiber length and its uniformity: These parameters play critical role
in deciding the combing performance. If the fiber has high short
fiber content, then the improvement in the yarn quality becomes
significant only on removal of high amount of noil, which will in turn
increase the material cost.
II. Fiber stiffness: If the fiber stiffness is high, there is good chance of
fiber breakage during the combing operation as the fibers have to
go through lot of bending during the combing operation.
III. Moisture content: High moisture content is the fibers make the
combing operation difficult since the fibers tend to cling to each
other making the passage of the combing needles between the
fibers rather difficult leading to improper combing and high fiber
breakage. If the moisture content is less and the fibers are dry, then
the fibers do not move smoothly from one component to another
and they tend to fly.
Cont…
IV. Fiber fineness: The combing machine parameters like the
speeds and settings will be influenced by the micronaire
value of the cotton being processed. In case of finer
fibres, the total number of fibres in a unit length of the
lap of given linear density will be much higher than that
for coarser fibres. The finer fibres are also delicate.
Hence, the combing machine parameters need to be
selected appropriately.
V. Foreign material associated with the fibers: The foreign
materials and larger trash particles should have been
already removed from the fibers at the carding stage
itself. If larger trash particles and metallic particles are still
left in the feed lap, they can cause damage to the
combing needles.
3.Material preparation:
I. Fiber parallelization: The condition of fibres in terms of
orientation and parallelization as they are feed to the
combing head is a very critical parameter which decides
the combing performance.
Parallelization of the feed fibres depends upon the draft
between card and the combing machine. If the fibres are
not oriented (parallelized), then long fibres are presented
to the circular comb as if they are short fibres and they are
therefore eliminated as noil.
At the same time, too high parallelization is also not desired.
During detaching, a few fibres reaching the nip of the
detaching rollers are drawn out of the thick layer of
feedstock.
The Combing Process: Removing Neps and Improving Fiber Quality

Weitere ähnliche Inhalte

Was ist angesagt?

Drawing frame and its machine parts
Drawing frame and its machine partsDrawing frame and its machine parts
Drawing frame and its machine partsRidoy Dey
 
Introduction of modern loom
Introduction of modern loomIntroduction of modern loom
Introduction of modern loomFuad Ahmed
 
Simplex frame
Simplex frameSimplex frame
Simplex frametemesggen
 
1.3 preparation of combing
1.3 preparation of combing1.3 preparation of combing
1.3 preparation of combingAmit Biswas
 
Shuttle less weaving
Shuttle less weavingShuttle less weaving
Shuttle less weavingRanita Paul
 
Carding,card clothing,grinding, autoleveller.pdf
Carding,card clothing,grinding, autoleveller.pdfCarding,card clothing,grinding, autoleveller.pdf
Carding,card clothing,grinding, autoleveller.pdfGoldentuch
 
Honeycomb, Mock Leno, Huckaback weaves and Dobby Figure Designs
Honeycomb, Mock Leno,  Huckaback weaves and Dobby Figure Designs Honeycomb, Mock Leno,  Huckaback weaves and Dobby Figure Designs
Honeycomb, Mock Leno, Huckaback weaves and Dobby Figure Designs Azmir Latif Beg
 
Picking Mechanism | Beat Up Mechanism | Over Picking Under Picking Mechanism
Picking Mechanism | Beat Up Mechanism | Over Picking Under Picking MechanismPicking Mechanism | Beat Up Mechanism | Over Picking Under Picking Mechanism
Picking Mechanism | Beat Up Mechanism | Over Picking Under Picking MechanismMd Rakibul Hassan
 
Simplex machine. Roving, sliver
Simplex machine. Roving, sliverSimplex machine. Roving, sliver
Simplex machine. Roving, sliversrsujandiu
 

Was ist angesagt? (20)

Drawing frame and its machine parts
Drawing frame and its machine partsDrawing frame and its machine parts
Drawing frame and its machine parts
 
Introduction of modern loom
Introduction of modern loomIntroduction of modern loom
Introduction of modern loom
 
Carding machine
Carding machineCarding machine
Carding machine
 
Simplex frame
Simplex frameSimplex frame
Simplex frame
 
1.3 preparation of combing
1.3 preparation of combing1.3 preparation of combing
1.3 preparation of combing
 
Ring frame
Ring frame Ring frame
Ring frame
 
Conventional loom and modern loom
Conventional loom and modern loomConventional loom and modern loom
Conventional loom and modern loom
 
Yarn Manufacturing Process : Comber Part II [Modern combers]
Yarn Manufacturing Process : Comber Part II [Modern combers]Yarn Manufacturing Process : Comber Part II [Modern combers]
Yarn Manufacturing Process : Comber Part II [Modern combers]
 
Draw frame
Draw frameDraw frame
Draw frame
 
Rieter modern blow room line
Rieter  modern blow room lineRieter  modern blow room line
Rieter modern blow room line
 
Shuttle less weaving
Shuttle less weavingShuttle less weaving
Shuttle less weaving
 
Carding,card clothing,grinding, autoleveller.pdf
Carding,card clothing,grinding, autoleveller.pdfCarding,card clothing,grinding, autoleveller.pdf
Carding,card clothing,grinding, autoleveller.pdf
 
Advanced weft systems
Advanced weft systemsAdvanced weft systems
Advanced weft systems
 
Honeycomb, Mock Leno, Huckaback weaves and Dobby Figure Designs
Honeycomb, Mock Leno,  Huckaback weaves and Dobby Figure Designs Honeycomb, Mock Leno,  Huckaback weaves and Dobby Figure Designs
Honeycomb, Mock Leno, Huckaback weaves and Dobby Figure Designs
 
Rapier loom
Rapier loomRapier loom
Rapier loom
 
Moisture in textile
Moisture in textileMoisture in textile
Moisture in textile
 
Picking Mechanism | Beat Up Mechanism | Over Picking Under Picking Mechanism
Picking Mechanism | Beat Up Mechanism | Over Picking Under Picking MechanismPicking Mechanism | Beat Up Mechanism | Over Picking Under Picking Mechanism
Picking Mechanism | Beat Up Mechanism | Over Picking Under Picking Mechanism
 
Simplex machine. Roving, sliver
Simplex machine. Roving, sliverSimplex machine. Roving, sliver
Simplex machine. Roving, sliver
 
Draw frame (1)
Draw frame (1)Draw frame (1)
Draw frame (1)
 
Draw frame
Draw frameDraw frame
Draw frame
 

Ähnlich wie The Combing Process: Removing Neps and Improving Fiber Quality

Ähnlich wie The Combing Process: Removing Neps and Improving Fiber Quality (20)

Presentation
PresentationPresentation
Presentation
 
Presentation
PresentationPresentation
Presentation
 
Combing
CombingCombing
Combing
 
Air jet-spinning-of-cotton-yarns
Air jet-spinning-of-cotton-yarnsAir jet-spinning-of-cotton-yarns
Air jet-spinning-of-cotton-yarns
 
Abhi rana)4. dry laid non woven fabrics
Abhi rana)4. dry laid non woven fabricsAbhi rana)4. dry laid non woven fabrics
Abhi rana)4. dry laid non woven fabrics
 
function of card frame in process control in spinning.docx
function of card frame in process control in spinning.docxfunction of card frame in process control in spinning.docx
function of card frame in process control in spinning.docx
 
spinning
spinningspinning
spinning
 
Fibre to yarn
Fibre to yarnFibre to yarn
Fibre to yarn
 
Warping and details
Warping and detailsWarping and details
Warping and details
 
Cotton Yarn Quality Depends on Mixing Strategy
Cotton Yarn Quality Depends on Mixing StrategyCotton Yarn Quality Depends on Mixing Strategy
Cotton Yarn Quality Depends on Mixing Strategy
 
Yarn evenness_AyBee Marwat
Yarn evenness_AyBee MarwatYarn evenness_AyBee Marwat
Yarn evenness_AyBee Marwat
 
ROTOR SPINNING PROCESS
ROTOR SPINNING PROCESSROTOR SPINNING PROCESS
ROTOR SPINNING PROCESS
 
Quality control in the knitting process
Quality control in the knitting processQuality control in the knitting process
Quality control in the knitting process
 
Drawing and texturising
Drawing and texturising Drawing and texturising
Drawing and texturising
 
Yarn Hairiness
Yarn HairinessYarn Hairiness
Yarn Hairiness
 
Chapter 3 work aids, velcro & sewing thread
Chapter 3 work aids, velcro & sewing threadChapter 3 work aids, velcro & sewing thread
Chapter 3 work aids, velcro & sewing thread
 
15571089 yarns
15571089 yarns15571089 yarns
15571089 yarns
 
yarns
yarnsyarns
yarns
 
Mechanics of Composite Materials
Mechanics of Composite MaterialsMechanics of Composite Materials
Mechanics of Composite Materials
 
Yarn spining...
Yarn spining...Yarn spining...
Yarn spining...
 

Kürzlich hochgeladen

Employablity presentation and Future Career Plan.pptx
Employablity presentation and Future Career Plan.pptxEmployablity presentation and Future Career Plan.pptx
Employablity presentation and Future Career Plan.pptxryandux83rd
 
STRAND 1 FOUNDATION OF PRETECHNICALSTUDIE.pptx
STRAND 1 FOUNDATION OF PRETECHNICALSTUDIE.pptxSTRAND 1 FOUNDATION OF PRETECHNICALSTUDIE.pptx
STRAND 1 FOUNDATION OF PRETECHNICALSTUDIE.pptxkimdan468
 
The Shop Floor Overview in the Odoo 17 ERP
The Shop Floor Overview in the Odoo 17 ERPThe Shop Floor Overview in the Odoo 17 ERP
The Shop Floor Overview in the Odoo 17 ERPCeline George
 
Scientific Writing :Research Discourse
Scientific  Writing :Research  DiscourseScientific  Writing :Research  Discourse
Scientific Writing :Research DiscourseAnita GoswamiGiri
 
Jordan Chrietzberg In Media Res Media Component
Jordan Chrietzberg In Media Res Media ComponentJordan Chrietzberg In Media Res Media Component
Jordan Chrietzberg In Media Res Media ComponentInMediaRes1
 
BÀI TẬP BỔ TRỢ 4 KĨ NĂNG TIẾNG ANH LỚP 11 (CẢ NĂM) - FRIENDS GLOBAL - NĂM HỌC...
BÀI TẬP BỔ TRỢ 4 KĨ NĂNG TIẾNG ANH LỚP 11 (CẢ NĂM) - FRIENDS GLOBAL - NĂM HỌC...BÀI TẬP BỔ TRỢ 4 KĨ NĂNG TIẾNG ANH LỚP 11 (CẢ NĂM) - FRIENDS GLOBAL - NĂM HỌC...
BÀI TẬP BỔ TRỢ 4 KĨ NĂNG TIẾNG ANH LỚP 11 (CẢ NĂM) - FRIENDS GLOBAL - NĂM HỌC...Nguyen Thanh Tu Collection
 
4.9.24 Social Capital and Social Exclusion.pptx
4.9.24 Social Capital and Social Exclusion.pptx4.9.24 Social Capital and Social Exclusion.pptx
4.9.24 Social Capital and Social Exclusion.pptxmary850239
 
Geoffrey Chaucer Works II UGC NET JRF TGT PGT MA PHD Entrance Exam II History...
Geoffrey Chaucer Works II UGC NET JRF TGT PGT MA PHD Entrance Exam II History...Geoffrey Chaucer Works II UGC NET JRF TGT PGT MA PHD Entrance Exam II History...
Geoffrey Chaucer Works II UGC NET JRF TGT PGT MA PHD Entrance Exam II History...DrVipulVKapoor
 
CHUYÊN ĐỀ ÔN THEO CÂU CHO HỌC SINH LỚP 12 ĐỂ ĐẠT ĐIỂM 5+ THI TỐT NGHIỆP THPT ...
CHUYÊN ĐỀ ÔN THEO CÂU CHO HỌC SINH LỚP 12 ĐỂ ĐẠT ĐIỂM 5+ THI TỐT NGHIỆP THPT ...CHUYÊN ĐỀ ÔN THEO CÂU CHO HỌC SINH LỚP 12 ĐỂ ĐẠT ĐIỂM 5+ THI TỐT NGHIỆP THPT ...
CHUYÊN ĐỀ ÔN THEO CÂU CHO HỌC SINH LỚP 12 ĐỂ ĐẠT ĐIỂM 5+ THI TỐT NGHIỆP THPT ...Nguyen Thanh Tu Collection
 
16. Discovery, function and commercial uses of different PGRS.pptx
16. Discovery, function and commercial uses of different PGRS.pptx16. Discovery, function and commercial uses of different PGRS.pptx
16. Discovery, function and commercial uses of different PGRS.pptxUmeshTimilsina1
 
Sarah Lahm In Media Res Media Component
Sarah Lahm  In Media Res Media ComponentSarah Lahm  In Media Res Media Component
Sarah Lahm In Media Res Media ComponentInMediaRes1
 
Pastoral Poetry, Definition, Origin, Characteristics and Examples
Pastoral Poetry, Definition, Origin, Characteristics and ExamplesPastoral Poetry, Definition, Origin, Characteristics and Examples
Pastoral Poetry, Definition, Origin, Characteristics and ExamplesDrVipulVKapoor
 
Advancing Gender Equality The Crucial Role of Science and Technology 4 April ...
Advancing Gender Equality The Crucial Role of Science and Technology 4 April ...Advancing Gender Equality The Crucial Role of Science and Technology 4 April ...
Advancing Gender Equality The Crucial Role of Science and Technology 4 April ...EduSkills OECD
 
Farrington HS Streamlines Guest Entrance
Farrington HS Streamlines Guest EntranceFarrington HS Streamlines Guest Entrance
Farrington HS Streamlines Guest Entrancejulius27264
 
ICS 2208 Lecture Slide Notes for Topic 6
ICS 2208 Lecture Slide Notes for Topic 6ICS 2208 Lecture Slide Notes for Topic 6
ICS 2208 Lecture Slide Notes for Topic 6Vanessa Camilleri
 
Objectives n learning outcoms - MD 20240404.pptx
Objectives n learning outcoms - MD 20240404.pptxObjectives n learning outcoms - MD 20240404.pptx
Objectives n learning outcoms - MD 20240404.pptxMadhavi Dharankar
 
How to create _name_search function in odoo 17
How to create _name_search function in odoo 17How to create _name_search function in odoo 17
How to create _name_search function in odoo 17Celine George
 
How to Uninstall a Module in Odoo 17 Using Command Line
How to Uninstall a Module in Odoo 17 Using Command LineHow to Uninstall a Module in Odoo 17 Using Command Line
How to Uninstall a Module in Odoo 17 Using Command LineCeline George
 

Kürzlich hochgeladen (20)

Chi-Square Test Non Parametric Test Categorical Variable
Chi-Square Test Non Parametric Test Categorical VariableChi-Square Test Non Parametric Test Categorical Variable
Chi-Square Test Non Parametric Test Categorical Variable
 
Employablity presentation and Future Career Plan.pptx
Employablity presentation and Future Career Plan.pptxEmployablity presentation and Future Career Plan.pptx
Employablity presentation and Future Career Plan.pptx
 
STRAND 1 FOUNDATION OF PRETECHNICALSTUDIE.pptx
STRAND 1 FOUNDATION OF PRETECHNICALSTUDIE.pptxSTRAND 1 FOUNDATION OF PRETECHNICALSTUDIE.pptx
STRAND 1 FOUNDATION OF PRETECHNICALSTUDIE.pptx
 
Israel Genealogy Research Assoc. April 2024 Database Release
Israel Genealogy Research Assoc. April 2024 Database ReleaseIsrael Genealogy Research Assoc. April 2024 Database Release
Israel Genealogy Research Assoc. April 2024 Database Release
 
The Shop Floor Overview in the Odoo 17 ERP
The Shop Floor Overview in the Odoo 17 ERPThe Shop Floor Overview in the Odoo 17 ERP
The Shop Floor Overview in the Odoo 17 ERP
 
Scientific Writing :Research Discourse
Scientific  Writing :Research  DiscourseScientific  Writing :Research  Discourse
Scientific Writing :Research Discourse
 
Jordan Chrietzberg In Media Res Media Component
Jordan Chrietzberg In Media Res Media ComponentJordan Chrietzberg In Media Res Media Component
Jordan Chrietzberg In Media Res Media Component
 
BÀI TẬP BỔ TRỢ 4 KĨ NĂNG TIẾNG ANH LỚP 11 (CẢ NĂM) - FRIENDS GLOBAL - NĂM HỌC...
BÀI TẬP BỔ TRỢ 4 KĨ NĂNG TIẾNG ANH LỚP 11 (CẢ NĂM) - FRIENDS GLOBAL - NĂM HỌC...BÀI TẬP BỔ TRỢ 4 KĨ NĂNG TIẾNG ANH LỚP 11 (CẢ NĂM) - FRIENDS GLOBAL - NĂM HỌC...
BÀI TẬP BỔ TRỢ 4 KĨ NĂNG TIẾNG ANH LỚP 11 (CẢ NĂM) - FRIENDS GLOBAL - NĂM HỌC...
 
4.9.24 Social Capital and Social Exclusion.pptx
4.9.24 Social Capital and Social Exclusion.pptx4.9.24 Social Capital and Social Exclusion.pptx
4.9.24 Social Capital and Social Exclusion.pptx
 
Geoffrey Chaucer Works II UGC NET JRF TGT PGT MA PHD Entrance Exam II History...
Geoffrey Chaucer Works II UGC NET JRF TGT PGT MA PHD Entrance Exam II History...Geoffrey Chaucer Works II UGC NET JRF TGT PGT MA PHD Entrance Exam II History...
Geoffrey Chaucer Works II UGC NET JRF TGT PGT MA PHD Entrance Exam II History...
 
CHUYÊN ĐỀ ÔN THEO CÂU CHO HỌC SINH LỚP 12 ĐỂ ĐẠT ĐIỂM 5+ THI TỐT NGHIỆP THPT ...
CHUYÊN ĐỀ ÔN THEO CÂU CHO HỌC SINH LỚP 12 ĐỂ ĐẠT ĐIỂM 5+ THI TỐT NGHIỆP THPT ...CHUYÊN ĐỀ ÔN THEO CÂU CHO HỌC SINH LỚP 12 ĐỂ ĐẠT ĐIỂM 5+ THI TỐT NGHIỆP THPT ...
CHUYÊN ĐỀ ÔN THEO CÂU CHO HỌC SINH LỚP 12 ĐỂ ĐẠT ĐIỂM 5+ THI TỐT NGHIỆP THPT ...
 
16. Discovery, function and commercial uses of different PGRS.pptx
16. Discovery, function and commercial uses of different PGRS.pptx16. Discovery, function and commercial uses of different PGRS.pptx
16. Discovery, function and commercial uses of different PGRS.pptx
 
Sarah Lahm In Media Res Media Component
Sarah Lahm  In Media Res Media ComponentSarah Lahm  In Media Res Media Component
Sarah Lahm In Media Res Media Component
 
Pastoral Poetry, Definition, Origin, Characteristics and Examples
Pastoral Poetry, Definition, Origin, Characteristics and ExamplesPastoral Poetry, Definition, Origin, Characteristics and Examples
Pastoral Poetry, Definition, Origin, Characteristics and Examples
 
Advancing Gender Equality The Crucial Role of Science and Technology 4 April ...
Advancing Gender Equality The Crucial Role of Science and Technology 4 April ...Advancing Gender Equality The Crucial Role of Science and Technology 4 April ...
Advancing Gender Equality The Crucial Role of Science and Technology 4 April ...
 
Farrington HS Streamlines Guest Entrance
Farrington HS Streamlines Guest EntranceFarrington HS Streamlines Guest Entrance
Farrington HS Streamlines Guest Entrance
 
ICS 2208 Lecture Slide Notes for Topic 6
ICS 2208 Lecture Slide Notes for Topic 6ICS 2208 Lecture Slide Notes for Topic 6
ICS 2208 Lecture Slide Notes for Topic 6
 
Objectives n learning outcoms - MD 20240404.pptx
Objectives n learning outcoms - MD 20240404.pptxObjectives n learning outcoms - MD 20240404.pptx
Objectives n learning outcoms - MD 20240404.pptx
 
How to create _name_search function in odoo 17
How to create _name_search function in odoo 17How to create _name_search function in odoo 17
How to create _name_search function in odoo 17
 
How to Uninstall a Module in Odoo 17 Using Command Line
How to Uninstall a Module in Odoo 17 Using Command LineHow to Uninstall a Module in Odoo 17 Using Command Line
How to Uninstall a Module in Odoo 17 Using Command Line
 

The Combing Process: Removing Neps and Improving Fiber Quality

  • 1. THE COMBING PROCESS Introduction The process of straightening and parallelizing of fibers and the removal of short fibers and impurities by using a comb on combs assisted by brushes and rollers is called combing.  The combing process is carried out in order to improve the quality of the sliver coming out of the card. The process eliminates short fibers, it achieves better parallelization of fibers, it straightens curls, and it removes neps and residue impurities.
  • 2. Objectives (tasks)of Combing Following are the objectives of combing process:  To remove naps in the carded sliver.  To make the fiber more parallel and straight.  To produce a uniform sliver of required per length.  To remove the fiber shorter than a predetermine length.  To remove remaining impurities in the comber lap. Necessity of Combing The following quality of fibers can only be obtained by combing  Absence of nap  More parallel arrangement of fibers  Straight fibers  Clean finer fiber  Uniformity in length of fiber
  • 3. FACTOR INFLUENCING THE COMBING PROCESS 1. Machine settings I. Feed distance:- This indicates the distance fed by the feed roller per cycle; high feed distance increases the production rate but, reduces the comber noil and deteriorates the quality. However, % noil and feed rate relationship is different for forward and backward feed systems Feed distance also very much depends upon the staple length. Fig Cm-5 indicates typical values of feed distance for different length of cotton fiber.
  • 4. Cont.. II. Feed type:- Feeding can take place when the nippers move backwards (known as backward feed or counter-feed) and alternatively, when nippers move forward (known as forward feed or concurrent feed) during a combing cycle. Counter- feed is used when better quality of product is required at the loss of more noil (12-25%). Concurrent feed is preferred when higher production rate with less noil desired (5-12%).
  • 5. Cont… III. Detachment setting:- This is one of the main settings responsible for the change of noil percentage. This setting refers to the distance between the bite of the nippers and the nip of the detaching rollers when nipper assembly is at the most advance position. A closer setting is associated with lower noil level. Detachment setting normally lies in the range of 15-25 mm. A large setting (more than optimum) does not produce further improvement in quality, but results in more loss of noil. As such, optimum setting has to be found out depending on quality and production level desired for a particular machine and material processed.
  • 6. Cont… IV. Number of point on comb; Saw tooth clothing is used in circular comb and needles are used in top comb. Fineness and point density depend on the raw material processed. Usually top comb point density falls in the range 23-32 needles per centimeter. More needles give more noils. V. Depth of penetration of top comb:- Lowering of the top comb by about 0.5 mm is followed by an increase in noil of about 2%. The main improvement is seen in elimination of neps. Over deep penetration of the top comb disturbs fiber movement during piecing and so optimum penetration is very important.
  • 7. Cont… VI. Piecing and detachment timing:- During piecing, fiber fringes are laid on top of each other in the same way as roofing tiles. Sliver produced in this way has a wave like structure due to this piecing having a wavelength of 30-75 cm. This is known as piecing defect. • The combed fiber fringes can be compared with very flat parallelogram although the leading edge is blunter. By using correct setting (by adjusting the timing when detaching begins relative to the instant at which the fringe protruding from the nipper reaches the nip line of the detaching rollers), it is possible to lay the fringes on each other in such a way that unevenness in successive fringes partly cancels out. On the other hand, incorrect settings will cause an increase in unevenness arising from piecing.
  • 8. 2.Properties of raw material I. Fiber length and its uniformity: These parameters play critical role in deciding the combing performance. If the fiber has high short fiber content, then the improvement in the yarn quality becomes significant only on removal of high amount of noil, which will in turn increase the material cost. II. Fiber stiffness: If the fiber stiffness is high, there is good chance of fiber breakage during the combing operation as the fibers have to go through lot of bending during the combing operation. III. Moisture content: High moisture content is the fibers make the combing operation difficult since the fibers tend to cling to each other making the passage of the combing needles between the fibers rather difficult leading to improper combing and high fiber breakage. If the moisture content is less and the fibers are dry, then the fibers do not move smoothly from one component to another and they tend to fly.
  • 9. Cont… IV. Fiber fineness: The combing machine parameters like the speeds and settings will be influenced by the micronaire value of the cotton being processed. In case of finer fibres, the total number of fibres in a unit length of the lap of given linear density will be much higher than that for coarser fibres. The finer fibres are also delicate. Hence, the combing machine parameters need to be selected appropriately. V. Foreign material associated with the fibers: The foreign materials and larger trash particles should have been already removed from the fibers at the carding stage itself. If larger trash particles and metallic particles are still left in the feed lap, they can cause damage to the combing needles.
  • 10. 3.Material preparation: I. Fiber parallelization: The condition of fibres in terms of orientation and parallelization as they are feed to the combing head is a very critical parameter which decides the combing performance. Parallelization of the feed fibres depends upon the draft between card and the combing machine. If the fibres are not oriented (parallelized), then long fibres are presented to the circular comb as if they are short fibres and they are therefore eliminated as noil. At the same time, too high parallelization is also not desired. During detaching, a few fibres reaching the nip of the detaching rollers are drawn out of the thick layer of feedstock.