abhinav fr bala sir
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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?
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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
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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.
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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?
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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.
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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.):
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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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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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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):
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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)
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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)
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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.)
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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
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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
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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
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