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    ADVANCED FLAT KNITTING

    LEARNING DIARY

    ABHINAV VERMA

    KNITWEAR DESIGN

    SEMESTER-VI

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    Brief Content:

    1. Preparation of material for knitting

    2. Bases of knitting technology

    3. Knitted structures

    4. Working and controlling systems of

    knitting machines

    5. Yarn supply

    6. Fabric take-off

    7. Checking equipment

    8. Machine drives

    9. Knitted technical textiles 1/2

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    0. Introduction

    Advantages of knitting:

    High productivity

    Great variability (wide usage)

    Possibilities ofshaping (ready-made clothes)

    Wasteless production

    History:

    Archaeology rests of knitted fabrics from 6-th century

    Mechanical knitting reverend William Lee 1589

    invention of the first knitting machine

    No revolutionaryinventions such as shuttleless weaving

    and open end spinning in knitting. Why? 1/3

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    1. Preparation of material for knitting

    Which properties should have yarn

    packages, suitable for knitting? How is it possible to improve yarn

    properties? Which properties are

    suitable for knitting process? Is material preparation necessary?

    1/4

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    A. Aims of material preparation

    The knitting system should be supplied by:

    Yarn of appropriate quality without defects,

    which could cause problems in knitting(thick places in yarn, parts of low

    strength).

    Yarn flexible, with low friction coefficient.

    Yarn should have suitable axial tension with

    low variability.

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    Reason for yarn properties:

    Yarn must bear multiplied bend and tensilestress increase when high speed is used ...

    Yarn must fit into given gap g

    1/6

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    Changes in yarn speed and stress

    Speed vy corespons with speeds ofl1, l2, l3 change,

    is variable.

    Tensile force F is increased by friction. 1/7

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    Main operations of yarn preparation:

    The most important operation is yarn (yarns)

    rewinding:

    Individual yarnswinding

    Many yarnswarping

    Main aims of yarn rewinding:

    To form the yarn body ofsuitable geometry and

    mass (why extremes are not good?).

    To remove imperfect cuts of yarn, to decrease

    friction and increase flexibility.

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    Other operations of yarn preparation:

    Twisting (folding) of spun yarn reduction of

    torsion moment, increase of yarn durability.

    Texturing of multifilament.

    Bulking of some yarns (some fibers shrinks).

    Twisting or covering ofmultifilament yarns.

    Economical impact of preparation: the costs,

    caused by problems at knitting, are higher.

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    B. Knitting materials (yarns)

    Suitableyarns: soft and bulky with similarcharacter as knitted fabric, and so:

    Spun yarns with lower twist.

    Multifilament usually textured. Yarns forming stitches (loops) should be

    uniform, flexible, of sufficient strength, with

    low friction. Yarns not forming stitches may have another

    properties (even flex, glass, carbon fibers etc.

    could be used). 1/10

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    Multifilament without twist problems when

    some filament is broken (creates bunches or

    neps, could be kept by neighboring yarns ):

    Impact of twist:

    migration of fibresoccurs each

    filament is

    alternatively on thesurface and inside

    the yarn.

    1/11

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    C. Preparation of individual yarns

    Unwinding in knitting

    process:

    Sometimes is

    interrupted, we

    cannot rely on

    creation ofballoon.

    How to eliminate

    yarn to bobbin

    friction?

    1/12

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    Usual bobbines (packages, cross-winding):

    a) Conical (with higher slant cone angle).b) Vario-conical (slant increases with diameter).

    c) Bi-conical with lower slant (cone). Why? It is

    necessary to receive sufficient compactness if

    material of low friction is used.

    1/13

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    Winding machines:

    Drive can be realized:

    From axis (tube)enables precise winding. Peripheral (bobbin rolls on driving drum) chaotic

    winding.

    Yarn preparation (lubrication) by:

    Solid matterparaffin (for spun yarns).

    Liquid matter (oil etc., for multifilament).

    Yarn stretching (definition of axial tension):

    Setting of yarn elongation.

    Necessary for bobbin compactness.

    Checking of yarn strength.

    Yarn cleaning (sensors: photoelectrical, capacitive).

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    Change of position of yarn layers:

    Through winding, next yarn layers presses toprevious and push them near the package axis

    the yarn is shortened.

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    Precise and chaotic winding:

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    Drive (a from axis, b peripheral):

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    Peripheral drive by grooved drum:

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    Automatic winding machine, individual control:

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    Automatic winding machine, group control:

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    Automatic winding machine automate doffing:

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    Small rewinding machine (yarn rests etc.):

    1/22

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    Yarn cleaningUster Classimat (tester):

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    Fancy yarn folding:

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    Fancy yarn folding (loop yarn):

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    D. Preparation of warps

    Warpmany yarns. Knitting from giant

    creel is not suitable, usual is to wind many

    yarns on one beam.

    Necessary conditionsimilar length of all

    yarns in the fabric.

    If the yarn consumption is individual(patterned fabric) it is necessary to use

    creel.

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    1. Section warping

    Narrow warp beams are used, several ofthem form final warp.

    Advantage only one yarn rewinding.

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    Shape of the warp beam

    Yarn body shapeshould be cylindrical

    (the same length of

    all yarns). Examples

    of errors:

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    1. Section warping

    Warping machine:

    1 beam; 2 pressure drum; 3 reeds; 4

    electrostatic charge eliminators; 5 working

    table; 6 warp magazine; 7 photoelectrical

    sensor; 8 creel

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    1/30

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    Section warping example of machine1/30

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    2. Beam warping

    For lower yarns number are used so called pattern

    beams a set of X-wound bobbins on 1 tube:

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    2. Basics of knitting technology

    2.1 Basic principles

    What are specific features of knitting,

    from which basic elements it is

    composed?

    How to save material at knitting?

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    Is it at all possible?

    May fabric beformed from one

    system of yarns

    with fixed all ends?

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    Yes, by change in yarn geometry

    Forming of kink(loop) on then yarn

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    Mutual interlooping of kinks

    Repeatedly kinks ofthe yarn are pulled

    through similar

    element from

    another yarns.

    Advantage: easy fabric creation (short movements).

    Disadvantage: easy destruction (symmetrical

    structure . 1/35

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    Basic elements:

    Kink (loop) of yarn (open, closed). Knitted stitch or loop (F - face, R reverse side).

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    Groups of elements:

    CourseWales.

    aWeft, bwarp knitted fabric.

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    Loops in warp knitted structures:

    Yarn input: from previous course from the right or the

    left side Yarn output: into next course to the right or the left side

    Asymmetrical stitches

    mean worse shape

    stability of fabric

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    Another basic elements:a) Tuck stitch (two loops are interlooped with

    one stitch) with only two crossing points

    b) Float stitch (on back or reverse of the loop)

    c) Facefloat stitch (on face of the loop)

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    1/40

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    Knitted products:

    Continuous fabric -

    Yardage (metrage) flat a,

    tubular b.

    Pieces or panels:

    Not shaped c

    In-plane shaped d, e,

    Spatial-shaped f (or 3-

    D shaped).

    1 welt (fast starting c.)

    2 separating course

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    Example of products (sock):

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    l f d ( l )

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    Example of products (glove):

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    l f d ( )

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    Example of products (cap):

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    l f d ( ifi i l i )

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    Example of products (artificial vain, stent):

    44

    2 2 P tt i d l ifi ti f

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    2.2 Patterning and classification of

    knitted structures

    Is it really necessary to draw knitted

    structures by loop diagram?

    It is possible to create system

    (classification) of knitted structures?

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    Wh d i i ?

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    What does it means patterning?

    Symbolic (simplified) representation ofstructure notation.

    Topological description of yarn interlooping

    without respect on dimensions and shape. Weft structures many possibilities, no of

    them is ideal (we shall try 3 systems: Prusa,

    VUP, English). Warp structures one generally used

    system.

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    S t f P f P (A t i )

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    System of Prof. Prusa (Austria):

    It is not dependanton colors.

    Ideal for structures

    with loop transfer.

    Only local use.

    1 face stitch

    2 reverse stitch

    3 tuck stitch

    4, 5 transferred

    stitches

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    E li h t

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    English system: Not providing an easy survey of structures with many

    courses i repetition.

    Widely used.

    Showing only 1

    knitted course1 face stitch (open!)

    2 reverse stitch

    (open!)3 tuck stitch

    4 float stitch

    5

    symbol of needle 1/48

    S t VUP (B CZ)

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    System VUP (Brno CZ):

    Uses the most common symbols (alphabet;

    some systems use X instead of V). Chosen symbols resembles appearance of

    knitted elements.

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    W k itt d t t

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    Warp knitted structures:

    The scheme of yarn path in fabric or yarn lay-

    in on needles.

    1 knitted stitch (overlap)

    2 float (underlap)

    1/50

    Cl ifi ti f t t l

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    Classification of structures classes:

    WeS - Weftsingle faced (1 type of stitches)

    WeD - Weftdouble faced (Face and Reverse

    wales)

    WeP - Purl (F. and R. stitches in 1 wale)

    WeI - Interlock (2 intermeshed WeD)

    WaS - Warp single faced (1 type of stitches)

    WaD - Warp double faced (F. and R. wales)

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    Cl ifi ti f t t

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    Classification of structures groups:

    1. Structures with full stitches number (all-knit). Thebest utilisation of machine productivity.

    2. Structures with missing stitches. Some needles arenot active (temporarily or permanently).

    3. Structures with tuck stitches.4. Structures with complementaryyarns. To the basic

    structure some other yarns are added. These yarnsare not necessary for fabric integrity. Connection

    with basic structure by double stitches, tucks or byanother way.

    5. Structures with loop transfer of with anotherstructure modification.

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    2.3 Basic actions of knitting machines

    What enables knitting needle to catch

    and keep new yarn and simultaneously

    to release (knock-over) old stitch?

    How the activities of needles are

    coordinated in the course formation?

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    The types of knitting needles:

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    The types of knitting needles:

    Knock-overof old loop 4:a) By swing of the latch 2

    (latch needle).

    b) By pressing of longflexible hook (bearded

    needle).

    c) By independentlycontrolled latch 3 (bi-

    partitecompound needle)

    1/54

    Examples of needles:

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    Examples of needles:

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    Non traditional knitting principle:

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    Non-traditional knitting principle:

    Revolving knittingelement till now

    not practically used

    (Czech invention;problems with

    elements bedding

    etc.)

    1/56

    Stitch formation (latch needle):

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    Stitch formation (latch needle):

    Positions and phases:

    a) Normal (basic)

    b) First tuck

    c) Clearing

    d) Second tuck + yarn

    feeding

    e) Latch closing

    f) Knock-over

    g) Loop length formation

    1/57

    Stitch formation wave:

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    Stitch formation - wave:

    1. Needle track

    2. Trick wall3. Cams

    4. New yarn

    5. Needle buts

    6. Old stitches

    7. Hook of needle on

    stitch cam

    8. Yarn feeder

    vw working speed

    vn-c speed of needles

    relatively to cams

    1/58

    Warp knitting (yarns feeding):

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    Warp knitting (yarns feeding):

    Simultaneousfeeding of many

    yarns on many

    needles. It is necessary:

    to supply at

    least one yarnon each needle

    in each course.

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    IntroductionSeamless knitting technology creates one entire

    complete garment with minimal or no cutting and

    sewing process. This innovative technology

    eliminates post labor work, which saves productionand time cost. In addition, the technology offers

    knitwear consumers more comfort and better fit by

    eliminating seams. Thus, seamless technology

    provides benefits to manufacturers as well as endusers. Seamless knitting technology ha entered the

    mainstream in the knitwear market.

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    There are no. of different methods that can be

    used to produce seamless products.

    The seamless knits are in tubular shape, which is

    produced by high elongation yarns, Circular knitting

    machines were mostly used to make seamlessclothes.

    This leads to saving of production costs up to 35%

    compared to the cut and sew methods.

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    Year Historical Events Contributing to Development of Seamless Knitting

    1589 William Lee in England invented the first flat-bed frame to create hosiery.

    1863 Issac W. Lamb invented the first operational V-bed flat knitting machine including the latchneedles.

    1864 William Cotton of Loughborough patented his rotary-driven machine that used a flat bed toproduce fully-fashioned garments

    1800s The flat knitting machine was fitted with sinkers, which controlled stitches in order to knitsingle jersey tubular articles such as gloves, socks and berets.

    1940 The manufacture of shaped knitted skirts using a flechage technique was patented in theUSA.

    1955 The Hosiery Trade Journal reported on the automatic knitting of traditional berets throughthe shaped sections.

    1960s Shima Seiki company further explored the tubular-type knitting principle to produce glovescommercially.

    1960's Courtaulds established British patents on the idea of producing garments by joining tubeknitting.

    1995 Shima Seiki introduced seamless entire garment knitting at ITMA.

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    Methods Of Production

    Seamless clothing can be produce by followingmethods:

    Partially machine process

    (Pasting method)

    Fully machine process

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    Linked windows

    options of fabric design viewand technical view.

    STOLL Knit and Wear

    Machine (Stoll)

    F ll M hi P

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    Fully Machine Process

    Seamless garment can also be produce by followingMachines.

    V-bed flat knitting machines

    Circular knitting machines

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    Pasting Method

    This method and system makes possible a seamlessgarment finish that is more comfortable than a finish

    having seams and other imperfections due to the needto tuck/sew edges and joints.

    The disclosed seamless technology employs a thin filmof adhesive that is preferably ether-basedpolyurethane although other adhesives are acceptable.

    This adhesive is pre-laminated on at least onesurface prior to lamination to another surface underconditions to control adhesion, stretch, breathability,and longevity of the garment.

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    Joining Options

    Welding, bonding, and heat sealing are other

    options then customary sewing method.

    However, these options have their restrictions over

    elasticity.

    Framis Italia, based in ltaly, is well-known for its

    welding technology, NoSo that is based on bonding.

    It is bonding of two fabrics together.

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    Seamless MachinesShima Seiki

    Stoll

    Shima Seiki WholeGarment Stoll Knit-and-Wear

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    Shima Seiki WholeGarment

    Machines

    Stoll Knit and Wear

    Machines

    Knitting Width 50 80 (126 203 cm ) 72 84 (183 213 cm)

    Gauge 5 - 18 gauge 5 -18 gauge

    Knitting Speed Max 1.3m/sec Max 1.2m/sec

    Racking Max 3 total Max 4 total

    Knitting System 34 systems 34 systems

    Transfer Simultaneous transfer Simultaneous transfer

    Sinker System Spring-type movable full sinkersystem

    Spring-type moveable holding-down sinker system

    Yarn Carriers Up to 16 Up to 16

    Take-down Device Main/sub take down rollers Main/upper take down rollers

    Needle Selection Electric selection system Electric selection system

    Needle Latch needles, Compoundneedles,Slide needles

    Latch needles

    CAD system Integrated knit productionsystem

    allowing planning, design,evaluation and production

    Complete design, patterning, andprogramming system

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    Applications

    Sleeveless Shirt

    Inner wears

    Air bags

    Hand gloves

    Hats

    Socks

    Sweaters

    Trousers

    Skirts

    Bandages

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    Advantages

    Freedom of body movement: Generally the seam portion of any garment is not

    having the same elasticity as compared to the body

    fabric, so the difference in elasticity will affect the

    free body movement.

    Since the seamless garment doesnt have anyseam in it structure this problem has been

    eliminated.

    Wider range of fit for different range of body

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    shapes:

    In a single garment measurement can suitable forwider range of fit for different range of body shapes

    because of its higher elasticity

    Inherent softness:

    There are no bulky and annoying stitches at the

    underarm points, shoulders and neck lines, which

    may cause irritation to the wearer, since the

    garment having seam free structure it provides the

    soft feel only.

    It reduces labour cost:

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    Due to the elimination cutting and sewing process

    it is obvious to reduce more labour involvement

    Engineered features like comfort, fit, and

    ventilation we can obtain from this technology.

    Minimum yarn consumption:

    Most of the fabric wastages occur at cutting

    stage, since this seamless garment excludes this

    process fabric consumption per garment is less, so

    the yarn consumption also very low.

    Smaller work space:

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    Involvement of sewing operation is less except

    few cases in the garment production system, which

    leads less space requirement.

    Reduce yarn and fabric inventory:

    Cutting and sewing process require more fabric aswell as yarn inventory due the absence of this

    process no need of maintaining huge inventory.

    Fewer product failure:Most of the garment failures are due to seam

    failure the seamless garment doesn't have the

    seam, so that garment failure is also very less.

    Quick samples:

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    Quick samples:

    Sampling is a costly as well as time consuming

    process, because small portion of fabric as well

    accessories need to be prepared, since this seamless

    garment is exemption, here we can prepare quick

    samples.

    Cost of production is less:

    This leads to saving of production costs up to 40percent compared to the customary garment

    production system

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    Design possibilities:

    Seamless garment Technology not only to create

    several types of tubular formed knitting but also to

    build diverse design structures on the tubular

    knitted garments simultaneously.

    Just in time production:

    Just-in-time production is possible with the help ofseamless technology.

    Technical Issues

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    Technical Issues

    Although seamless garment knittingtechnology provides a variety of advantages forthe knitting industry, it still has several technicalissues.

    The main problem in complete garment

    knitting is fabric take up5.Maintaining the tension of each loop (i.e.,stitch) is difficult.

    Fabric design as well as garment design on

    jacquard is highly difficult task. Problem to make the welt and cuff portions.

    Frequent changes in the knitting machine setting