Comparative Study of Various Break Drafts on Ne 20 PC (30:70) Blended Ring Spun Yarn

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COMPARATIVE STUDY OF VARIOUS BREAK DRAFTS ON Ne 20 PC (30:70) BLENDED RING SPUN YARN





By

1. Sanaullah (GL) ......................................07TE69
2. Muhammad Saeed Shah (AGL) ............07TE30
3. Deedar Ali .............................................07TE62
4. Ahsan Gaffar Malano .........................07TE108
5. Zahid Ali ..............................................07TE58
6. Mir Javed-Ul-Rehman Rahoo ..............07TE82
7. Faisal Latif Gul ....................................07TE49


Supervised By
ENGR: SAMANDER ALI MALIK

Submitted in partial fulfillment of the requirement for the degree of Bachelor of Textile Engineering
DEPARTMENT OF TEXTILE ENGINEERING
MEHRAN UNIVERSITY OF ENGINEERING AND TECHNOLOGY, JAMSHORO, PAKISTAN
December, 2010


DEDICATED TO

THE HOLLY PROPHET
HAZRAT MUHAMMAD (PBUH)
Who is the most knowledgeable among all creations of ALLAH Almighty

&

To our Parents
They support and courage us in any field of life and
To our venerated Teachers who take us to the doorsill of
knowledge.



ABSTRACT
  1. Break draft has great influence on yarn characteristics, it depends on TM, yarn fineness and hank of roving.
  2. This study aims to investigate the appropriate B.D for Ne 20 PC (30:70) ring spun yarn.
  3. Ne 20 PC blended yarn was manufactured on EJM-168 ring frame at different break draft levels i.e, 1.20 to 1.49.
  4. Yarn was Investigated for uniformity and IPIs at UT-4 and for tensile properties at UTR-4.
  5. The results indicate that for the production of Ne 20 PC blended yarn with 1.2 hank roving and 0.95TM, the optimum characteristics may be achieved at break draft 1.25.

CHAPTER 01
INTRODUCTION

1.1 Blending:
Blending is defined as mixing together two different components/fibers or same fibers of differing characteristics to form a single product (yarn), that yarn is termed as blended yarn.

A Blend is a fabric or yarn made up of more than one type of fiber. The combination of two or more types of staple fibers and/or colors in one yarn. Blending is the mixing process of various fibres. It normally mixes fibres of different physical properties to ensure a consistent finished product.

Blends are sometimes so intimate that It is difficult to distinguish component fibers in yarn or fabric. A highly sophisticated textile art, blending today is creating new fabric types, performance characteristics, and dyeing and finishing effects. A yarn obtained when two or more staple fibers are combined in a textile process for producing spun yarns (e.g., at opening, carding, or drawing). A fabric that contains a blended yarn (of the same fiber content) in the warp and filling. A yarn/fabric which is made out of more than one fiber. In blended yarn, more than two different types of staple fibers are twisted or spun together to form yarn.

Two or more fibers combined in one fabric to bring out the best qualities of each. Example: In a cotton/polyester blend, cotton supplies softness and breath ability; polyester supplies strength and easy-care advantages. Usually referred to by two numbers such as 60/40, with each number representing the percentage of each fiber present in the yarn. Describes cloth woven or knitted from yarn or thread made of two or more kinds of fibers. A term applied to a yarn or a fabric that is made up of more than one fiber. In blended yarns, two or more different types of staple fibers are twisted or spun together to form the yarn. Examples of a typical blended yarn or fabric is polyester/cotton.

Blending cotton/polyester fibers is common practice in the textile industry. In comparison with 100% cotton, cotton/ polyester blends have higher breaking and abrasion strength, crease resistance, are more comfortable to wear, and display better easy-care properties. On the other hand, in comparison with 100% polyester, cotton/polyester blending has many advantages such as less pilling, less static electrification, easier spinning, better evenness for sliver, roving and yarn . It is a critical problem in fibre blending technology to choose appropriate method of blending, types of fibers and blend ratios depending on the final product. This study aims to check the quality and properties of Ne 20’s PC (30:70) blended yarn produced by drawframe blending techniques at ring spinning machine.

The blending of a relatively weak fiber (i.e., cotton) with a strong fiber (i.e., polyester) leads, as expected, to some losses in yarn strength. The properties of the blended yarns cannot merely be explained in terms of the proportions of the different constituent fibers in the blends. In fact, the overall properties of the blended yarns are related to the blend ratios, the corresponding properties of each component and the interactions of the components themselves.

The number of fibers in the yarn cross-section affects the mechanical properties of the yarn. When the blended yarn is subjected to a force, the fibers of both components will be elongated as the force increases, until the fibers with smaller elongation break and so transfer the entire load to other fibers. If there are enough fibers with higher elongation in the yarn cross-section, the blended yarn will not break. Fiber slippage plays a particularly important role when component fibers in a blended yarn have different values of fiber breaking elongation.

1.2 Types of blending
Blending operation may be classified into blow given two types;

1.2.1 Intimate blending
Mixing of fibers of two different types or of different characteristics but of same fiber type before carding is called as ‘Intimate Blending’, in this type of blending the fibers are mixed more vigorously, this process is not used frequently in Pakistan for two different fiber types but frequently used for the same fiber type i.e. Cotton.

1.2.2 Drawframe blending
Blending several slivers (i.e 4-10) of two different fiber types or of same fiber type at drawframe is termed as drawframe blending. This is the most famous blending technique used for production of blended yarn of two different fibers, therefore; this blending technique is also termed as ‘conventional blending’.

The most part, blending of the natural and synthetic fibers is still carried out in sliver form on the draw frame. This provides the best blend in the longitudinal direction. Up to the draw frame, each raw material can be processed separately on the machines best suited to it. For this, blending material is processed three times on the draw frame by suitable arrangement of the sliver cans of the both type of fibers.

1.3 Blending types & stage of processing
Blending can be carried out at various stages, by using various methods, equipments, machines, and intermediate products. The following can distinguish:

Blend type ..............................Process stage

Bale mixing ............................ before the blow room
Flock blending ....................... within the blow room
Lap blending ...........................by using scutchers
Web blending ..........................at the ribbon-lap machine or the blending draw frame
Sliver blending ........................at the draw frame, the sliver- lap machine or the Comber
Fiber blending .........................at the card or the OE-spinning machine
Roving blending ......................at the ring spinning machine

1.4 Purpose of blending
Raw materials used in the spinning mill are always inhomogeneous in their characteristics .This is due to different cultivation conditions of cotton fibers and different production conditions for synthetic fibers.

The main purposes of blending are as:
  1. To give the required characteristics to the end product; s
  2. To compensate for variations in the characteristics of the raw materials;
  3. To hold down raw material-costs;
  4. To influence the favourably the behaviour of the material during processing;
  5. To achieve effects by varying colour, fiber characteristics, and so on
1.5 Objectives of blending
The main objectives of blending of fibers are given below:

1.5.1 Improvement in Functional Properties
A 100% single fibre yarn cannot impart all the desired properties to a fabric. For example100% viscose rayon suffer from low tensile strength, poor crease resistance and low abrasion resistance.
Similarly 100% polyester fabrics are not desirable as they are prone to static accumulation, hole melting and pilling. They are moisture resistant, difficult and expensive to dye and have a poor hand.

These negative attributes of polyester and viscose can be reasonably neutralised by addition of a certain percentage of each fibre.

1.5.2 Improved Process performance
Some fibres like polyester at times are quite troublesome to work in 100% form especially at cards. Addition of fibres like cotton or viscose rayon in the previous process has been seen to facilitate the smooth carding of such fibres.

The blending of manmades which are longer and finer to cotton which is shorter influences the spinnablility as well as productivity.

1.5.3 Economy
The price of manmades is much more stable than that of natural fibres like cotton. Price stability can enable the mills to pursue optimisation of their fibre purchase programme.

Blending could also be used for reducing the mixing cost. For example, a fibre like viscose can be blended with cotton for producing specific yarns with reduced raw material costs.

1.5.4 Fancy Effect
Fibres with a variety of colour mixture or shades can be produced by blending different dyed fibres at the blowroom, drawframe or roving stage.

1.5.5 Aesthetics
The aesthetics of a fabric can be developed by selecting specific blend components and their properties.

1.6 Evaluation of blending
The evenness of the blend must always be assessed in two directions:
  1. The longitudinal direction
  2. The transverse direction
Where there is unevenness in the longitudinal direction, successive yarn portions exhibit different percentage distributions of the individual components. These can lead to stripiness.

Where there is unevenness in the transverse direction, the fiber are poorly distributed in the yarn section. This irregularity leads to an uneven appearance of the finished product.

The determination of the evenness of a blend e.g. of synthetic and natural fibers, is costly and not simple. One component is usually dissolved out or coloured differently.

1.7 How to select Blend Constituents
Selection of Blend Constituents depends upon the following factors:

1.7.1 Type of Fibre
  1. Depending upon the end use of the fabric, blend constituents are chosen.
  2. For example, it is well known hat a polyester-cotton yarn looks fuller as compared to the lean look of polyester-viscose yarn.
  3. Therefore for light constructions like shirtings, polyester-cotton blend is used.
  4. However polyester-viscose blend is preferred for medium and heavy construcitons such as suitings.
1.7.2 Compatibility of blend fibres
Compatibility must be there in terms of the following properties:

a. Length and Denier of Fibres
  • As a general rule, these two fibre properties should be nearly the same for all the constituents.
  • For example in a viscose rayon cotton blend, the rayon staple of 1.5 denier and 29-32 mm length is generally used since the cotton component used has a denier of around 1.5 and a length of 28mm.
b. Extensibility
  • A large difference in the breaking elongation of the fibres in a blend adversly affects the yarn tenacity.
c. Density
  • The blend fibres should preferably have the same density. Any large differences on this account will lead to selective separation while conveying the blended stock through ducts under the influence of air suction in the blow rooms.
d. Dispersion Properties
  • This property describes the ability of an individual fibre to separate from its group and disperse thoroughly within the fibre matrix of the blend to produce an intimate and homogeneous blend.
e. Drafting Properties
  • Some fibres like viscose are outstanding it terms of draftability. These fibres, when blended with other fibres act as good carriers to obviate the trouble relating to drafting.
f. Dyeing Properties
  • In case the blend yarn or fabric is to be dyed subsequently, due consideration should be given to the dyeing properties of individual fibre components.
1.8 Yarn
Yarn may be defined as a continuous, twisted strand of spun able fibers which has received its final attenuation and which has been twisted sufficiently, give the strength necessary to make possible its use in weaving, knitting or other manufacturing operations.

Yarn is a long continuous length of interlocked fibers, suitable for use in the production of textiles, sewing, crocheting, knitting, weaving and rope making. Yarn can be made from any number of synthetic or natural fibers.

Continuous strand of fibers grouped or twisted together and used to construct textile fabrics. Yarns are made from both natural and synthetic fibers, in filament or staple form. Filament is very long fiber, including the natural fiber silk and the synthetic fibers. Most fibers that occur in nature are fairly short, or staple, and synthetic fibers may be cut into short, uniform lengths to form staple. Spinning is the process of drawing out and twisting a mass of cleaned, prepared fibers.

Yarn consists of several strands of material twisted together. Each strand is, in turn, made of fibers, all shorter than the piece of yarn that they form. These short fibers are spun into longer filaments to make the yarn. Long continuous strands may only require additional twisting to make them into yarns. Sometimes they are put through an additional process called texturing.

Yarn is used to make textiles using a variety of processes, including weaving, knitting, and felting.

Yarn is assembly of fine strand of fibers being twisted to gather in order to make it suitable for further processes as weaving, knitting. The essential requirement in producing the yarn from staple fibers is to make the fiber hold together by twisting to gather. There are various processes involved in producing the yarn but twisting process is the most famous process, widely used in industries. Many spinning techniques were used to convert fibers into yarn. Some of them remained common such as Ring and Rotor. The production of Ring and Rotor yarn have great share in the world market.

1.8.1 Ring Spun Yarn
Spinning is the art of producing continuous, twisted strands, of desired size, form fibrous material. The characteristics of spun yarn depend, in part, on the amount of twist given to the fibers during spinning. A fairly high degree of twist produces strong yarn; a low twist produces softer, more lustrous yarn; and a very tight twist produces crepe yarn.

The ring spun yarn possessed good desirable properties such as strength, evenness, fineness etc. this type of yarn produced when roving of fine fibers is being drafted in drafting zone and twisted between high speed spindle and traveler.

The properties of ring spun yarn vary with the variation in amount of draft and twist. The ring spun yarn has quality/property to use for weaving either in warp yarn or weft yarn.

1.9 Quality
ISO standard 4802 defines quality as that “ensembles of properties and characteristics of a product or a service, which confer on it the capacity to satisfy expressed or implicit requirements”. This definition clearly illustrates a concept, which in a more synthetic manner, can be summed up by the expression “suitably for use”.

1.9.1 Quality Assessment
After the manufacturing of yarn it is necessary to check the quality of the yarn that either the required properties were achieved or not .Therefore quality assessment is necessary step after production or in production line.

Quality assessment consists of testing of cotton fiber and yarn testing which includes, staple length, fineness, and strength of cotton and polyester fibers. Yarn testing includes, count, twist, evenness testing, single yarn strength, lea strength and microscopic view of yarn.

1.9.2 Yarn Quality
The quality of yarn gives us view/ opinion about the properties and characteristics of the yarn which are also necessary requirements of further process and product. So it is very important to investigate and to inspect the physical and mechanical behavior and properties of yarn for to bear further stresses and strains in weaving and knitting. The investigation testing should be done on those instruments which are calibrated and set according to standards otherwise quality of yarn will be deteriorate. In weaving or knitting construction, the quality of yarn plays vital role

1.10 Aims & Objectives of Study
As discussed earlier (section 1.2) that the blended yarn is produced by two different methods and that blending is achieved at one of the processing stage (section 1.3). This thesis/resaerch work aims as under:
  1. To prepare Ne 20 PC (30:70) blnded yarn at ring frame by carying the break draft in steps from 1.20 to 1.49.
  2. To check the yarn properties i.e tenacity and elongation% on UTR-4
  3. To check the U%, CV and yarn IPI at UT-4
Following are the various qualitative parameters which will be considered in the study;
  • CV% & U%
  • Evenness
  • Hairiness
  • Neps
  • Thick & Thin places
  • Various yarn properties also compared in this research work for example;
  • Tenacity
  • Elongation %
All these parameters are being cheked at well established standards of ASTM. The laboratories used for yarn production and testing of yarn are well maintained to fulfill our following objectives.
  • Raw material testing
  • Preparatory processes of Spinning
  • Yarn production
  • Yarn testing
This study will help us to select appropriate break draft at ring frame for Ne 20 PC blended yarn.

CHAPTER 02
MATERIAL, MACHINES, PROCESS & SETTINGS

2.1 Material
The fibers are considered as the raw material for the production of yarn that may be defined as “The unit of matter has flexibility fineness and high ratio of length to thickness”. Polyester and Cotton blend is most widely used blend, it should be kept in mind while mixing these fibers that the cut length of polyester fiber must compete with cotton staple fiber. Otherwise cotton fibers not gait twist with polyester and cause more hairiness.

Cotton Fiber Characteristics ....................... Polyester Fiber Characteristics

SL2.5% = 28.73 mm                                   Cut length = 38 mm
Fineness = 4.63 μg/in                                  Mic-value = 1.2 denier
Trash content = 7.2 %                                   - -
Invisible trash = 3.7 %                                  - -
Tenacity = 7 g/tex                                         Tenacity = 6.8 g/tex
Colour = Grade C                                          Colour = Semi dull
Cross-section = Ear Shape                             Cross-section = Circular

2.2 Preparation for Spinning
Usually, raw material- cotton and polyester fibers, arrives in mill in form of compressed bales. That raw material must be processed further for the formation of yarn form, start from blow room to ring spinning machine. For conventional blending first both materials processed separately up to sliver formation at Card and then on Drawing machine these both blended together by setting blend ratio.

2.3 Rieter Blow Room Machines Installed In Textile department
In blow room the machine are installed in setup of three production lines, as shown below


Figure 2.1: Blow Room machines lining of Textile Engineering Department
2.3.1 Speed and Setting adjustments at Mixing bale opener (B-3/4R)
The raw material in form of small flock after manually opening of bale was placed in feed lattice of the bale opener. The inclined lattice delivered that material to opening / beater roller, where fibers were opened and cleaned with the help of grid bars placed underneath of beater. Then material is transferred to the next machine with the help of pneumatic system.

The setting of mixing bale opener B-3/4R, which used to process the cotton fibers were:
  • Production of machine = 400 kg/hr
  • Pressure of machine = 6 Bars
  • Speed of feed belt = 1.40 m/min 
  • Speed of conveyor belt = 9 m/min
  • Speed of spiked lattice = 100 m/min 
  • Speed of stripper roller = 591 m/min
  • Speed of cleaner roller = 739 m/min 
  •  Speed of take off roller = 292 m/min
  • Speed of feed roller = Speed of opening roller = 794 m/min
  • Clearance b/w spiked lattice and stripper = 20 mm
  • Clearance b/w cleaning roller and stripper = 10 mm
  • Clearance b/w spiked lattice and take off roller = 10 mm
  • Adjustment of feed roller rare panel = ½ of full width
  • Clearance b/w feed roller 80 mm and feed roller 60 mm = 1 mm
  • Clearance b/w opening roller and feed roller 60 mm = 2 mm (depending upon staple length)
  • Clearance b/w opening roller and grid knives = 1.5 mm (depending upon staple length)
  • Position of regulating flap = 20 mm
2.3.2 Uniclean (B - 11) settings
As its name implies that in this machine cleaning of material takes place. This machine has mechanical transport of material detached from transport air for low fiber loss. No clamping of material for negligible fiber damage and neps increase. The waste is moved in the waste compartment by an air tight rotary lock; from there it is moved by the waste transport system. This prevents unwanted loss of good fibers. The Uniclean also removes dust to a great extent; this is considered off beating point.

The setting of Uniclean B11 which were used to process the cotton fibers were:
  • Production of Uniclean B11 = 200 kg/hr
  • Cleaning intensity of machine = 0.5 or 720 rpm.
  • Relative amount of waste = 5
  • Gear motor speed = 24.8 RPM
2.3.3 Mixing opener (B-3/3)
After Uniclean B11 material is entered into mixing opener B3/3, in this machine further mixing of cotton fibers is takes place.

The setting of mixing opener B3/3 which used to process cotton fibers were:
  • Speed of feed belt = 1.25 m/min 
  • Speed of conveyor belt = 8 m/min
  • Speed of spiked lattice = 75 m/min 
  • Speed of stripper roller = 591 m/min
  • Speed of cleaner roller = 739 m/min 
  • Speed of take off roller = 292 m/min
  • Speed of feed roller = Speed of opening roller = 794 m/min
  • Clearance b/w spiked lattice and stripper = 20 mm
  • Clearance b/w cleaning roller and stripper = 03 mm
  • Clearance b/w spiked lattice and take off roller = 10 mm
  • Adjustment of feed roller rare panel = ½ of full width
  • Clearance b/w feed roller 80 mm and feed roller 60 mm = 1 mm
  • Clearance b/w opening roller and feed roller 60 mm = 2.5 mm (depending upon staple length)
  • Position of regulating flap = 20 mm
2.3.4 Uniflex (B- 60)
After leaving the mixing opener B3/3R the material entered to Uniflex B-60, in this machine high degree of cleaning is achieved having unidirectional feed for gentle fiber treatment. The Uniflex is the second perfect cleaner machine of the blow room line. The one roller concept allows a wide operating range with minimal fiber damage and maximum retention of good fibers.

The setting of Uniflex B 60 which were used:
  • Drum speed = 550 rpm
  • Machine efficiency = 90%
  • Stop and go ratio = 48%
  • Cleaning intensity = 0.5
  • Relative waste rate = 02
2.3.5 Chute feed (A - 70)
After Uniflex B 60 the material entered into chute feed system. The main function of chute feed system is to give an even feed of material to the card through an automatic sensing system.

2.4 Sliver formation
In the textile department there is a Rieter Hi performance card machine has production up to 120 kg/hr, it has fully automatic integrated grinding system, highly selective trash removal. A card opens the small flocks into individual fibers and removes any trash and neps. Dust and short fibers are also eliminated then in the last card sliver is formed. The card has capability of controlling the variations in the sliver by equipped long term auto levelers.

2.4.1 Technical data for production at HI-Per Card –C51
  • Sliver weight = 4.1 K Tex, 4.3 K Tex Polyester
  • Production = 30 – 35 kg/hr
  • Delivery = 125 m/min
  • Sliver weight / can = 25 kg
  • Sliver length = 800m
  • Machine efficiency = 80%
  • Type of coiler = CBA-3-600
  • Correction factor = 1.113
  • Feed wt: = 385 g/min
  • CV100 = 0.5
  • Total draft = 97.8
  • Coiler calendar delivery = 350 m/min
  • Cylinder speed = 400 rpm for cotton, 350 rpm for polyester & Blend
  • Taker-in speed = 1170 rpm for cotton, 1000 rpm for polyester & for Blend
  • Moveable Flats speed = Fast for cotton, slow for polyester & Blend
2.4.2 Settings at HI-Per Card – C51

2.4.2.1 Card settings for pure cotton

Setting between feed roller and taker-in = 0.9 mm
Nipping gauge = 16 (depending upon staple length)
Setting between 1st mote knife and taker-in = 1 mm
Setting between 2nd mote knife and taker-in = 0.35 mm
Setting between taker-in and cylinder = 0.30 mm
Setting between back bottom plate and cylinder = 1.20 mm
Setting between back stationary flats and cylinder = 0.55 mm, 0.55 mm, 0.5 mm
Setting between back mote knife and cylinder = 0.40 mm
Setting between back top plate and cylinder = 1.20 mm (bottom edge), 1.0 mm (top edge)
Setting between moveable flats and cylinder = 0.30 mm, 0.275 mm, 0.25 mm, 0.25mm, 0.25 mm
Setting between front top plate and cylinder = 1.0 mm (top edge), 0.80 mm (bottom edge),
Setting between front stationary flats and cylinder = 0.50 mm, 0.50 mm,
Setting between front mote knives and cylinder = 0.40 mm (top), 0.35 mm (bottom)
Setting between front bottom plate and cylinder = 1.0 mm
Setting between cylinder and doffer = 0.20 mm
Setting between cylinder and under-casing = 1.5 mm, 1.2 mm, 0.9mm, 2.0 mm
Setting between doffer and detaching roller = 0.15 mm
Setting between cleaning roll and detaching roller = 0.20 mm
Setting between detaching roller and transfer roll = 0.15 mm
Setting between delivery rollers = 0.20 mm
Setting of cross aprons = 1.50 mm (left side), 2.00 mm (right side)

2.4.2.2 Card settings for pure polyester

Setting between feed roller and taker-in = 0.9 mm
Nipping gauge = 17 (depending upon staple length)
Setting between 1st mote knife and taker-in = 1 mm
Setting between 2nd mote knife and taker-in = 0.35 mm
Setting between taker-in and cylinder = 0.30 mm
Setting between back bottom plate and cylinder = 1.20 mm
Setting between back stationary flats and cylinder = 0.50 mm, 0.50 mm
Setting between back top plate and cylinder = 0.90 mm (bottom edge), 1.0 mm (top edge)
Setting between moveable flats and cylinder = 0.40 mm, 0.375 mm, 0.35 mm, 0.35mm, 0.35 mm
Setting between front top plate and cylinder = 1.0 mm (top edge), 0.80 mm (bottom edge),
Setting between front stationary flats and cylinder = 0.50 mm, 0.50 mm,
Setting between front bottom plate and cylinder = 1.0 mm
Setting between cylinder and doffer = 0.20 mm
Setting between cylinder and under-casing = 1.5 mm, 1.2 mm, 0.9mm, 2.0 mm
Setting between doffer and detaching roller = 0.15 mm
Setting between cleaning roll and detaching roller = 0.20 mm
Setting between detaching roller and transfer roll = 0.15 mm
Setting between delivery rollers = 0.30 mm
Setting of cross aprons = 1.50 mm (left side), 2.00 mm (right side)

2.4.3 Drafts at different zones
  • Infeed draft = 1.23
  • Doffer – detaching roller = 1.09
  • Delivery rollers – stepped rollers = 1.31
  • Doffer – delivery = 1.17
  • Delivery rollers – cross apron = 1.08
  • Detaching - delivery rollers = 1.08
  • Doffer – cross apron = 1.26
  • Cross apron – stepped rollers = 1.22
  • Doffer to stepped roller = 1.53
  • Stepped rollers to calendar rollers = 1.02
2.4.4 Diameters of card rollers
  • Diameter of Taker-in = 25 3 mm
  • Diameter of cylinder = 1290 mm
  • Diameter of doffer = 500 mm
  • Diameter of detaching roller = 120 mm
  • Diameter of cleaning roller = 100 mm
  • Diameter of transfer roller = 75 mm
  • Diameter of delivery rollers = 80 mm, 80 mm
  • Diameter of stepped roller = 82 mm, 82 mm
  • Diameter of calendar rollers = 60 mm, 60 mm
2.5 Drawing of sliver
For doubling and drafting, the card sliver was transferred to the Draw frame, has model number RSB-D35 of Rieter. Here 7 slivers were doubled to produce I drawn sliver. For conventional blending two passages / times the slivers were doubled and drafted i-e breaker and finisher. These passages were given for to control and to minimize the irregularities and for to achieve an even blending of the drawn sliver.RSB-35 is a modern draw frame having autolevelling system to control sliver quality. It s objectives are; parallelization, equalization, sliver formation and dust removal.

2.5.1 Drawing frame settings
The settings of drawing frame are given in below given table.

Table: 2.1
Drawing
Adjustment
Breaker
For pc blend
Finisher
For pc blend
Creel tension
1.01
1.01
Feed Tension
1.00
1.00
Scanning roller height
6.5 mm
6.5 mm
Scanning roll pressure
120 da N
120 da N
Feed sliver weight
3.7 ktex (PP)
5.2 ktex (Co)
4.2 ktex
Doublings PC
(4+3)
7
Break draft
1.41
1.28
Total draft
8.24
7.88
Top rollers Pressure
380 N
380 N
320 N
200 N
380 N
380 N
320 N
200 N
Delivery tension
1.0
1.0
Roller settings
40 mm (F)
48 mm (B)
42 mm (F)
50 mm (B)
Condenser
3.8
3.8
Delivery speed
300 m/min
300 m/min
Delivered sliver weight
4.20 ktex
4.20 ktex
Tension belt
100
100
Length/can
450 m
400 m
Condenser
3.8 mm
3.5 mm
Web funnel
8F
8F

2.6 Roving formation
Roving is the first coherence strand having slight twist, The Simplex frame installed in Textile Engineering Department is a Chinese product, having model No: FA415A.

The objectives of roving are; attenuation, twisting and winding
The settings of machine were:
  • Motor speed = 1450 rpm
  • Main shaft pulley’s dia = 140 mm and 190 mm
  • Speed of main shaft = 856rpm
  • Front roller delivery speed = 15.5 inches per minute
2.6.1 Adjustments of simplex FA 415 A
  • Sliver fed = 4.2 ktex
  • Hank roving = 1.2 PC
  • TM for pc roving = 0.95
  • SPACER = Green
  • Roller pressure = G (F) --- R ---- R ----R(B)
  • Roller dia = 28.5, 28.5, 28.5, 28.5 mm
  • Roller gauge = 8.5, 20.5, 23.5,
  • Total Roller gauge = 37 ----- 49.5 --------- 52
  • Length of roving per bobbin 850 m
  • Number of doff = 5
  • Total draft = 18589.14/ CW4 * CW5 = 18589.14/ 44*52 = 8.12
  • F.D = 313.45/ CW4 = 7.123
  • B.D = 56.16/ CW5 = 1.08
  • T.D = 1. 056
  • TPI = TM √1.2 => 0.95 √1.2 = 1.04
  • Twist Set = CW1 = 50T, CW2 = 42T, CW3 = 48T
  • Lifter wheel (CW6) = 30T ie Winding/cm = 3.37
  • Traversing (Ratchet wheel CW7, Tension wheel CW 8) (45T,23T).
2.7 Spinning of ring yarn
For the production of ring spun yarn the roving is hung in the creel above the drafting zone of ring spinning machine. Then this roving is guided to back rollers of drafting zone of 3/3 double apron drafting system to front drafting zone, where the roving is attenuated well to attain the required count of yarn. Yarn gets the twist in between the section/space of front roller to steel ring with the help of traveler, revolving on steel ring. Due to speed difference of spindle and traveler the spun yarn is wounded onto the ring bobbin, held on spindle. The ring machine in Textile Engineering Department has model EMJ 168, made by China.

2.7.1 Settings at Ring Frame
The settings of ring spinning frame for the production of Ne 20 are given below.
  • Bottom rollers diameter = 27, 27, 27 mm
  • Top rollers diameter = 25, 25, 25 mm
  • Tin pulley diameter = 250 mm
  • Diameter of spinning wharves = 20.5 mm
Above settings are constant for all counts

Table: 2.2
Yarn LD
Adjustment
20 Ne
PC
Hank Roving
1.2
Total draft
16.67
Break draft
1.42
B.D Wheel
39T
TPM
754
Twist factor
4.25
Ring traveler
3/0
Spacer
Red
Spindle speed
15000 rpm
Arm pressure
Green
End use
Warp
Length in mtrs
30000
Za
34T
Zb
64T
Zc
62T
Zd
73T
Ze
87T
Zf
34T
Zg
132T

Settings for different yarn counts at ring frame

Note: Z (a, b, c) are twist wheels & Z (d, e, f, g) are Draft change wheels.

2.9 Testing
The testing is a way checks the quality of fiber and yarn properties according to well certified standards. Raw material represents about 50 to 70% of production cost of short staple yarn. This fact is sufficient to indicate the significance of the raw material for the yarn producer. It is not possible to use a problem-free raw material always especially cotton, because cotton is a natural fiber and has many problematic things in it, which will affect the performance. While the polyester staple fibers are produced according to required properties and qualities. To produce a good yarn with these difficulties, it is very necessary to get knowledge of raw material regarding their behavior in processing.

Mostly testing is done on the natural fiber, because it has not fixed length, width, shape and cross-section. The growth of natural fiber is responsible for this situation.

The atmosphere at which physical tests on textile material are performed must have relative humidity 65 ± 2 %RH and temperature of 20 C0. in tropical and sub tropical countries an alternative standard atmosphere for testing with relative humidity of 65 ± 2 and 27C0, may be used.

2.9.1 Fiber testing
Following are the basic fiber testing for cotton and polyester:
  • Fiber length
  • Fineness
  • Strength
2.9.1.1 Fiber length Tester
The length of cotton fiber is very important property for spinning of yarn, for performance and good characteristics of yarn. The length of cotton fibers is a property of commercial value as the price is generally based on this character. To some extent it is true as other factors being equal important, longer fibers gives better spinning performance than shorter ones.

The length value of cotton fiber is determined by Uster Fibro graph 730 with fibro sampler 192. The fibro graph 730 is a table top instrument that consists of an optical measuring system and the electronic components that necessary for the measurements and the supporting software.

It is used to measure the staple length of cotton fibers. The fiber comb, which was made by fibro sampler, was placed for the testing in the fibro graph. The instrument gives the measurements the optics system, a narrow beam of light is transmitted through the fiber beard. This light is collected and detected using a photo diode to determine the mass of the fibers in the optical path. Two span lengths, 2.5% span length, 50% span length and also short fiber index were measured. Knowing these quality characteristics of fibers a yarn manufacturer can better control the yarn spinning process to produce a consistent yarn.

Polyester fiber length was already given/ mentioned in purchasing quotation however in order to confirm that length we determined the length of polyester fiber with the help of comb sorter device.

2.9.1.2 Fiber Fineness Tester
The fiber fineness is another important quality characteristic, which plays a prominent part in determining the spinning value of cotton and polyester fibers. If the same count of yarn is spun from two varieties of fibers, the yarn spun from variety having finer fibers will have large number of fibers in its cross – section and hence it will be more even and than that yarn spun from sample of coarser fibers.

Fineness denotes the size of cross-section dimensions of the fiber. The fineness of polyester fibers was already known and expressed in deniers, which was same through out the length of fiber. As the cross-sectional features of cotton fibers are irregular, direct determination of the area of cross-section is difficult. The index of fineness, which is more commonly used, is the linear density or weight per unit length of the fiber. The unit in which this quantity is expressed varies in different parts of the world. The common unit used by many countries is micro gram per inch and the various air flow instruments of Uster Micronaire 775 are used to test the fineness of fibers. The Micronaire 775 is table top instrument that consists of an air system, the electronic components that are necessary for measurement and the supporting software. A weighing balance is required for measuring the sample before it placed in the chamber.

10 grams of cotton sample was weighted and placed in test chamber and then closed the door. The instrument automatically measures the flow of air through the test sample. The instrument software relates the air flow resistance to specific surface and provides the micronaire value for sample of cotton that was Mic-value = 4 – 5.

2.9.1.3 Fiber Strength Tester
The strength characteristics of the fibers can be determined either on individual fiber or bundle of fibers by using Uster Stelometer 754, which breaks the flat bundle of fibers. The breaking force is indicated in graduated scales, the force required to break the bundle of fibers and elongation of the fibers at the moment of breaking. The breaking force may be converted to breaking strength (Tenacity) by means of simple calculation when the length of fibers in bundle and weight of fibers are known. First of all fiber were clamped in pressley-type clamps, then that clamps were held in slots of pendulum and carrier. The carrier was locked to the loading arm by tightening the carrier –locking knob and position of carrier was adjusted with the carrier adjustment screw. The clamps were supplied with a removable 1/8” spacer, and then the cotton fibers were tested for tenacity at 1/8 gauge spacing and for testing polyester fibers 0” gauge was set. Then the broken bundles were weighted in digital weighing balance. By putting the acquired values of weight and breaking force we calculated the tenacity of the fibers.

Tenacity in gm/tex = breaking force in Kp x Spec: length in mm/ Specimen mass in mg.

2.9.2 Yarn Testing
Yarn occupies the intermediate position in the manufacturing of fabric from raw material. Yarn results are therefore essential, both for estimating the quality of raw material and for controlling the quality of produced. The important characteristics of yarn being tested are:
  • Linear density
  • Yarn evenness
  • Yarn elongation
  • Yarn strength
2.9.2.1 Linear Density or Yarn Count Tester
The fineness of the yarn is usually expressed in terms of its linear density or count of the lea. A lea of 120 yards is made on the lea winder, 5 samples are made in this way, found out the weight of that lea on weighing balance, and then the count is tested. The linear density of yarn is calculated by following formulas:
  • Count = Length in yards x 8.33/ Weight in grains
  • One gram = 15.43 grains
  • Count = Length in yards/ Weight in pounds
2.9.2.2 Yarn Strength and Elongation Tester
Breaking strength, elongation, elastic modulus, resistance abrasion etc. are some important factors, which will represent the performance of the yarn during actual use or further processing. Strength testing is broadly classified into two methods:
  • Single yarn strength testing
  • Skein / lea yarn testing
Above strength parameters are checked by Uster Tensorapid 4.

The digital tensile testing installation Uster Tensorapid 4 determines the breaking force the corresponding elongation of the textile and technical yarn skeins, fabric strips following the principle of constant rate of extension.

The high resolution, digital scanning of force/elongation characteristics of a test sample enables the computer to determine the additional values. In addition to this the force elongation characteristics can be recorded as a graphic display.

First of all single yarn strength was measured in Uster Tensorapid 4. After feeding the single yarn in the clamps, the lower clamp run downward with the determined speed. With this movement the sample was forced with a tensile stress and the measured force and the travel was the basic data for the evaluation. These values were transmitted to the control-unit and were out put as reports of various kinds.

2.9.2.3 Yarn Evenness Tester
Non-uniformity in variety of properties exists in yarn; there can be variation in the yarn fineness. This is the property, commonly measured, as the variation in the mass per unit length along the yarn, is basic and important one, since it can influences on so many other properties of the yarn and the fabric made from it. Such variations are inevitable, because they arise from the fundamental nature of the textile fibers and their resulting arrangement in the yarn.

The spinner tries to produce a yarn with the highest possible degree of evenness and homogeneity. In this connection, the evenness of the yarn mass is of the greatest importance. In order to produce an absolutely regular yarn, all fiber characteristics would to be uniformly distributed over the whole yarn.

The Uster Evenness Tester 4 is the digital instrument, with installation of capacitive sensor, was used determines the mass variations in yarn, roving, and sliver. Optional optical sensors allow the measurement of evenness, hairiness, surface structure and impurities in staple fiber yarns.

With the combination of test unit and integrated computer in the control unit, the system is capable of providing detailed information of tested material and presents the test results ion numerical and graphical form.

First of all the fed the yarn between the sensors then selected the length of yarn and yarn passed from sensors, which measures the mass variation, hairiness etc of the yarn. When the selected length was tested the yarn was taken out from the sensors and then connected printer will give the results that were measured by tester.

CHAPTER 03
RESULTS AND DISCUSSIONS

3.1 Introduction
In this chapter we have discussed the results of raw material (fibers) because raw material has significant influence on the subsequent processes and ultimate on the quality of end product. Therefore here we discuss different properties of both fibers utilized by us in the project i.e. Cotton and Polyester fibers.

Discussion on the characteristics of Sliver and Roving is also a part of this chapter; in this we compare both types of blended material.

The major part of this chapter is comprises of discussions on the results obtained from Ne 20 PC blended yarn.

3.2 Study of Fiber Properties
In this study we discuss most of the properties of (cotton and polyester) fibers, such as fiber length, fineness and strength etc.

3.2.1 Fiber Fineness
Fineness is one of the basic properties of fibers that are made into textile products. Fiber fineness has number of effects on the properties of yarn and fabric. The finer is the fiber the finer is the yarn that can be spun from it. The spinning limit that is the point, at which the fibers can no longer be twisted into a yarn, is reached earlier with coarser fibers.
  • Fineness of cotton fiber is measured in μg/inch; it ranges between 3-7.
  • The cotton used in this work has micronaire value = 4.3 μg/inch. (Medium)
  • The micronaire value of polyester fiber used in this study is = 1.2 denier.
  • The equipment used to measure cotton mic value is Micronaire 775TM.
3.2.2 Fiber Length
After fineness, length is the very important property of a fiber. For processing longer average fiber length is preferred, because with longer fibers evener yarn is produced due to less fiber ends in a given length of yarn, easy in process and a higher strength yarn is produced. Alternatively a yarn of same strength can be produced but with lower twist, thus giving a softer handle.

The length of cotton fiber used here is given below in table 3.1, measured on Uster Fibrograph730TM.

Table: 3.1
Different Cotton Fiber Parameters
Parameter
SL50%
SL2.5%
SFI
No:of Fiber
Uniformity
Mean Value
12.71 mm
28.73 mm
5.74
445
50.3




3.2.3 Fiber Strength
Strength is also a major property in which the quality and performance of upcoming processes depends. It is too hard and time taking job to determine single fiber strength; therefore bundle strength test is normally carried out for normal routine work in industries. It is performed either on Pressley fiber bundle tester or on Stelometer.

Cotton fiber bundle strength = 7 gf/tex
Polyester fiber strength = 6.8 gf/tex

3.3 Sliver Evenness
Sliver evenness has vital importance in the production of quality yarn because the quality of yarn depends upon the quality of roving, so, if the sliver is evener it helps to produce evener roving and consequently evener yarn.

Table: 3.2
Uster quality Report for ‘Drawframe blended’ Sliver of 4.2 Ktex

3.4 Roving Evenness
Evener roving is much more important to produce a yarn with better quality and other characteristics; it also helps to increase the efficiency of ring frame by reducing the breakage rate and draft problems. Following Uster Quality Report indicates quality of hank Roving 1.2.

Table: 3.3
Uster quality Report for ‘Creel blended’ Roving of 1.2 hank

3.5 Yarn Evenness
Yarn evenness can be defined as “the variation in weight per unit length of the yarn or as the variation in its thickness”. It is very important property of yarn for the assessment of its quality. Therefore it is considered in this study, it is found here that there are various imperfections that deteriorate the quality of yarn such as neps, thick places and thin places and hairiness etc. There are various ways to measure the yarn evenness. The Uster evenness tester is the most widely used equipment to measure yarn evenness by capacitive sensor. According to US Standards [4] the measured results are iven below for Different break drafts with count Ne 20.

3.5 Single Yarn strength
There are various standards used to measure the yarn’s strength and elongation. The British Standard [5] specifies 50 tests for single yarn by setting gauge length of 500 mm and speed up to 5000 mm/min and 0.5 cN/Tex as pre-tension on an automatic tensile strength tester, such as Uster Tensorapid-4.

The charts and tables above indicates that there is not sufficient effect of break draft on tenacity and elongation of yarn, only small variation is achieved in strength and elongation.

Chapter 04
Conclusion

From above study following conclusion are drawn:
  1. CV% and U% of yarn produce from 1.25 break draft is lesser than all other preparatory draft examined in this study.
  2. Thin and thick places of 1.25 break draft yarn is lesser than other applied break drafts.
  3. Hairness of 1.25 break draft yarn is little more than other break draft, which can be compromise with other properties.
  4. Elongation of single yarn at 1.25 break draft is greater than other applied break drafts while the tenacity is greater at 1.38 break draft but there is no significant difference in comparision with other break drafts.
  5. To sum up the whole it is concluded that 1.25 break draft is more appropriate for Ne 20`s PC (30:70) blended ring spun yarn produce from 1.2 hank roving with 0.95 TM in almost all aspects.
Suggestion for Future:
From this study we have investigated most of the yarn parameters such as quality, tensile properties, hairness, thick and thin places etc. For future work we suggest following main areas:
  1. Same work may be done for different counts and blend ratios.
  2. Same work may be done for two different fibers i.e, Viscose/PES or for any single fiber.
  3. Study about Microscopic appearance of yarn may be conducted.
References:
  1. Lunenschloss, J., Frey, M., ‘Die Mischung von Polyester-Fasern mit Baumwolle’, Meliand Textilberichte, 6-8-9/59.
  2. “Manual of Textile Technology” 2nd Edition, By: Werner Klei
  3. ”Manual of Textile” By: Gilbert R Merrill
  4. ASTM D 1425 The test method for unevenness of textile strands using Zellweger Uster capacitance testing equipment.
  5. BS 1932 Testing the strength of yarns and threads from packages.
  6. ASTM D 1578 Test method for breaking load (strength) of yarn by skein method.
  7. ISO 1833-1 Textiles-Quantitative chemical analysis-Part 1: General principles of testing.

Published By

Ahsan Gaffar Malano
B.Tech Engineer
Mehran University of Engineering and Technology,
Jamshro, Pakistan
 
 
 
 
 
 
 
 
 
 

1 comments:

Shuja Din said... Best Blogger Tips

nice work done, this will help the new engineers who r studying.
really happy to see the out standing work by Engr: Ahsan Ghaffar Malano.
Keep it up....

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