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Stitches and Seams
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Agenda
§ Stitch components
§ Stitch types
§ Seam types
§ Quality issues
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Stitch Components
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Stitch Components
Thread:
§ What types of thread are available, their properties, their ideal
uses and sewing applications
Machine needles:
§ Their descriptions and ideal uses
Adequate machinery:
§ Machinery that is capable of producing the desired stitch
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Thread Fiber Types
There are two types of thread fibers:
Natural fibers
§ Cotton
§ Rayon (derived from cellulose)
Synthetic fibers
§ Spun polyester
§ Core spun cotton & polyester
§ Textured polyester & nylon
§ Air entangled polyester
§ Continuous filament (CF) nylon & polyester
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Natural Fibers
Cotton:
§ Low Strength per size
§ Low elongation
§ Not as durable as synthetics
§ Colorfastness not as good as polyester
§ Good heat resistance
§ Wrap for core thread
§ Only available in staple
§ Ideal Application:
§ Over dye or garment dye programs
Rayon:
§ Medium strength
§ Low elongation
§ Low -wet modulus (low wet strength) i.e. it may shrink or stretch when washed
§ High sheen
§ Only available in continuous filament
§ Ideal application: Embroidery
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Synthetic Fibers
Spun polyester:
§ High strength per size
§ High elongation
§ Excellent chemical resistance
§ Good color fastness
§ Good abrasion resistance
§ Good UV resistance
§ Used in most apparel applications
§ Ideal applications:
§ Blouses and casual shirts
§ T-shirts with interlock weave
§ Sleepwear
§ Dresses
§ Lightweight twill pants
§ Medium range fleece
§ Sew applications:
§ Sews on most types of sewing equipment (lock stitch,chain-stitch, overedge)
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Synthetic Fibers
Corespun
§ High tensile strength
§ Excellent chemical resistance
§ Very good color fastness
§ Very good abrasion resistance
§ Very good UV resistance
§ Types
§ Cotton wrapped polyester core: Slightly higher purchase price than polyester wrap.Common thread for
all apparel and preferred by jeans makers.Repeated washing of jeans results in some fade down which is
also favored by some jeans manufacturers.
§ Polyester wrapped polyester core: Better color retention than cotton wrap; preferred by most industrial
garment manufacturers due to harsh laundry treatments.
§ Ideal applications:
§ Jeans and casual twills
§ Uniforms and Work wear
§ Dress shirts and blouses
§ Sew applications:
§ Sews on all types of sewing equipment with minimum sewing problems (lock stitch, chain, overlock, etc.)
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Synthetic Fibers
Textured
§ Most economical
§ This thread features high elongation and low cost
§ High bulk thread for excellent seam coverage and seam elasticity
§ Superior thread lubricant that allows it to be sewn with minimum thread tensions
§ Partially translucent so it blends in with many shades
§ Melts when temperatures exceed 480 degrees Fahrenheit
§ Cannot be used in a lock stitch machine for it will fall apart
§ Can snag on rough surfaces
§ Types:
§ Textured polyester (mid & regular tenacity)
§ Textured nylon
§ Ideal applications:
§ Active wear & fleece wear
§ T-shirts
§ Briefs, panties & lingerie
§ Sew applications:
§ Sews on overlock, cover stitch, and chainstitch machines (but no 301 lock stitch)
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Synthetic Fibers
Polyester/nylon continuous filament
§ High degree of resistance to abrasion
§ High strength
§ Can de used in heavy duty applications
§ Enhanced ultraviolet ray qualities
§ Types
Multifilament Monocord Monofilament (resembling fishing line)
§ Ideal applications:
§ Embroidery which needs to be resistant to enzyme washes for denim
§ Footwear
§ Rain gear
§ Sew applications:
§ Can be used on lock stitch machines
§ The monofilament thread can be used in blind stitch operations
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Synthetic Fibers
Air entangled
§ High initial modulus for excellent loop formation like cotton
§ Excellent seam durability-high loop strength
§ Excellent seam strength and durability
§ Very good chemical resistance
§ Very good abrasion resistance
§ Very good colorfastness
§ Less expensive than core and spun polyester thread
§ Melts when temperatures exceed 480º Fahrenheit, not as good resistance to needle heat
§ Types
§ Polyester
§ Ideal Applications:
§ All types of garments
§ Home furnishings
§ Sew Applications:
§ Sews on all types of sewing equipment (lock stitch,chain stitch,overedge,etc.)
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Thread Applications and Sizes
Fabric Weight Thread Tex Size
2-4 oz. Tex 16, 18, 21, 24
4-6 oz. Tex 24, 27, 30
6-8 oz. Tex 30, 35, 40, 50
8-10 oz. Tex 40, 45, 50, 60
10-14 oz. Tex 60, 80, 90, 105, 120, 135
Ideal Applications
Underwear,Lingerie,Bathing Suits
Shirts, Blouses T-Shirts, Microfibers
Slacks, Chinos, Jackets
Outerwear, Pants,Etc.
Denim Jeans,Heavy Coats,Leather
Tex Size:
§ Refers to a ticket size of sewing thread that is based on the gram weight of 1000
meters of greige (un-dyed) thread
§ Tex sizes are bracketed or rounded off to a smaller size
§ Example: Tex 42 thread would be labeled a Tex 40 thread
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Sewing Needles
§ A sewing machine needle is a
slender strand of metal, shaped to
precision that delivers thread to the
machine to create a stitch
§ Needles are found in various sizes,
and shapes:
§ Needles range in size from very fine
608 to a heavy duty needle 120/19
§ Most needles use the two number
measuring system
§ The higher number relates to the
metric system used in foreign
counties which defines the needle
shaft diameter in fractions of a
millimeter
§ The lower number relates to the
system in the U.S and is used to
indicate needle shaft diameter
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Bent overseam and
blindstitch needles
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Needle Point Types
§ Universal: Used for most woven and knit fabrics. The
point is slightly rounded, yet sharp enough to pierce
tightly woven fabrics,yet rounded enough to push
between the yarns of a knitted fabric.
§ Ballpoint: Point is slightly rounded. Use for stitching knit
fabrics. Helps to eliminate runs.
§ Stretch needle: For stitching knit fabrics that contain
spandex or Lycra®.
§ Jeans/denim needle: Very sharp point and stiff shank.
Used for stitching jeans, canvas and multiple layers.
§ Microtex sharp needle : Sharp point for stitching woven
fabrics, including silk and the newest micro fiber fabrics.
Use especially for edge stitching and topstitching.
§ Leather needle : Slight cutting point for stitching through
leather, suede, and vinyl. Never used on woven or knit
fabrics.
§ Self threading needle: General purpose needle with slip
in threading slot for those who have difficulty threading
needles.
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Needle Applications and Sizes
Fabric Weight
Light
Medium
Heavy
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Needle Size(millimeters) Ideal Applications
65, 70, 75. Underwear,Blouses,Tops
80, 90, 100, 110 Slacks, Chinos, Jackets
110, 120, 140, 160 Denim Jeans,Heavy Coats,Leather
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Sewing Machine Parts
Throat plate
Teeth/feed dog
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Stitch Forming Device
All stitch types are formed with a stitch forming device
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Sewing Machine Parts
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The Process
Thread + Needle + Sewing Machine = Stitches
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Stitch Types
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Stitches
Stitch:
A stitch is the formation of thread for the purpose of
making a seam. The elementary basis of sewing is the
stitch.
Stitch Type:
A series of recurring stitches of one configuration are
defined as a stitch type.
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Federal Stitch Types
Classification Description Popular Stitches Properties
100 Single Thread Chain Stitch 101 Basting & Button Sewing Least Amount of thread
103 Blindstitch
200 Handstitch Minor Applications,used in couture
and upper end tailoring.
300 Lockstitch 301 Plain Stitch Stitch is used in 90% of garments
Disadvantage: Bobbin W inding
(requires operator to stop and wind)
400 Multi thread Chainstitch 401 Single Needle Flexible stitch,reduces pucker,
406 Coverstitch but can chain off. Highly productive.
500 Serging & Safety Stitch 503 Two Thread Cuts and sews raw edges in one
504 Three Thread Serger operation. Highly productive.
512 Mock Safety
515 Four Thread Safety
516 Five Thread Safety
600 Coverstitch 602 Coverstitch Highly Productive
605 Coverstitch Requires a lot of thread
606 Coverstitch Produces a flat seam that is
607 Coverstitch gentle in contact with the skin.
700 Single thread lockstitch Rarely used stitch
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101 Chain Stitch
Chain stitch:
§ Single thread chain stitch:basting
stitch
§ Formed by 1 thread passing through
the material and inter looping with
itself on the underside of the seam
with the assistance of a spreader
§ Ideal application:
§ Single thread buttonholes
§ Bartacks
§ Button sew
§ 1 Needle, 1 spreader = 1 thread
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103 Blind Stitch
Blind stitch:
§ Formed by 1 thread which inter
loops with itself on the top surface
of the material
§ The thread passes through the top
ply and horizontally through portions
of the bottom ply without penetrating
the full depth
§ Ideal application:
§ Hemming
§ Waistbands
§ Joining shoulder pads
§ 1 Needle, 1 spreader = 1 thread
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301 Lock Stitch
Lock stitch:
§ Formed by a needle thread passing
through the material and
interlocking with a bobbin thread
with the threads meeting in the
center of the seam
§ Ideal application:
§ Topstitching
§ Joining
§ 1 Needle, 1 bobbin = 2 threads
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304 Zig Zag
Zig zag:
§ Formed with a needle and bobbin
thread that are set in the center of
the seam and form a symmetrical
zig- zag pattern
§ Also used to identify bar tacking and
lock stitch button sewing and
buttonholing
§ Ideal application:
§ Underwear
§ Lingerie
§ Decorative stitch
§ 1 Needle, 1 bobbin = 2 threads
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401 Chain Stitch
Chain stitch:
§ Formed by a single-needle, 2- thread
chain stitch double-locked stitch
§ Stitch is formed by one needle thread
passing through the materials and inter
looped with 1 looper thread that is set
on the underside of the seam
§ Ideal application:
§ Used for top stitching garment areas
where flexibility is needed, i.e.: the back
rise of a pair of jeans
§ 1 Needle, 1 looper = 2 threads
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406 Cover Stitch
Cover stitch:
§ Two needle, 3-thread bottom cover
stitch is formed by 2 needle threads
passing through the material and
inter-looping with 1 looper thread
with the stitch set on the underside
of the seam
§ Ideal application:
§ Hems on knit garments
§ Any area of a garment that needs a
stretch stitch
§ 2 Needles, 1 looper = 3 threads
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407 Cover Stitch
Cover stitch:
§ Three needle, 4-thread bottom
cover stitch is formed by 3 needle
threads passing through the
material and interlacing with 1
looper thread
§ Ideal application:
§ Any area of a garment that needs a
stretch stitch
§ 3 Needles, 1 looper = 4 threads
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503 Two Thread Overlock/Single Purl
Purl overlock:
§ Single-needle, 2-thread over edge
stitch formed by 1 needle thread
and 1 looper thread forming a purl
on the edge of the seam
§ For serging or serge hemmer (blind
hemming)
§ Ideal application:
§ Serging raw edges
§ 1 Needles, 1 looper = 2 threads
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504 Three Thread Overlock
3-Thread overlock:
§ Single needle, 3-thread over lock for
seaming is formed by 1 needle
thread and 2 looper threads forming
a purl on the edge of the seam
§ For over edge seaming and serging
§ Ideal application:
§ To join seams on knit garments
§ Serge raw edges of a seam
§ 1 Needle, 2 loopers = 3 threads
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505 Overlock Double Purl
Overlock Double Purl
§ Single needle, 3-thread over edge
with a double purl is formed by 1
needle thread and 2 looper threads
forming a double purl on the edge of
the seam
§ Used for serging only
§ Ideal application:
§ Used in serging raw edges
§ 1 Needle, 2 loopers = 3 threads
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512 Mock Safety Stitch
4-Thread/ Mock Safety Stitch
§ Stitch formed with 2 needle threads and 2
looper threads with the looper threads
forming a purl on the edge of the seam
§ 512 Right needle only enters the upper
looper
§ Ideal application:
§ Used in joining seams and has added
strength because this stitch will not chain off
§ Can be applied to knits and lightweight
woven fabrics
§ 2 Needle, 2 loopers = 4 threads
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514 4-Thread Overlock
Double needle, 4-thread over lock
§ Stitch formed with 2 needle threads and 2
looper threads with the looper threads
forming a purl on the edge of the seam
§ This stitch type will chain off
§ Ideal application:
§ Used in joining seams on knits where seam
flexability is important
§ 2 Needle, 2 loopers = 4 threads
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516 Safety Stitch
5-Thread Safety Stitch
§ Combination stitch consisting of
a single needle chainstitch (401)
and a 3 thread over edge stitch
(504) that are formed
simultaneously
§ Ideal application:
§ Joining seams on woven
fabrics, especially medium to
heavyweight fabrics
§ 2 Needle, 3 loopers = 5 threads
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602 Cover Stitch
Cover stitch:
§ 2 Needle 4-thread cover stitch or 2/N
top and bottom cover stitch is formed
with 2-needle threads, a top cover
thread and a bottom looper thread
§ Ideal application:
§ Stitches used for seaming knit
underwear or athletic wear which
provides excellent coverage on the top
and bottom side of the seam
§ This allows very flat seam constructions
§ 2 Needle, 1 top spreader, 1 bottom
looper = 4 threads
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605 Cover Stitch
Cover stitch:
§ 3 Needle 5-thread cover stitch or 3/N
top and bottom cover stitch is formed
with 3 needle threads, a top cover
thread and a bottom looper thread
§ Ideal application:
§ Flexibility and very flat seaming that can
be used in underwear
§ Mostly used in knit applications
§ Decorative stitch
§ 3 Needle, 1 top spreader, 1 looper = 5
threads
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606 Flat Lock
Flat lock:
§ Formed with 4 needle threads, 1 top
cover thread and 4 bottom looper
threads
§ Consumes a large amount of thread
§ More than 24” of thread an inch
§ Ideal application:
§ Used in knit applications that require
a flat seam
§ Mostly used for joining seams
§ 4 Needles, 1 spreader, 4 bottom
loopers = 9 threads
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607 Cover Stitch
Cover stitch:
§ 4 Needle, 6-thread flat seam or
4/N top and bottom cover stitch is
formed with 4-needle threads, a
top cover thread and a bottom
looper thread
§ Also referred to as “Butt” seaming
§ Ideal application:
§ The edges of the material are cut
and aligned during sewing so that
the seams feel flat and gentle
when they come into contact with
the skin
§ 4 needles, 1 top spreader, 1
bottom looper = 6 threads
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Inches of Thread per 1” of Sewing*
* = .050 Seam Thickness & 10 S.P.I
Stitch Type Description Inches of Thread
301 Lockstitch 3.0
401 Single Needle Chain 5.0
406 Coverseam 12.8
503 2 Thread Serger 11.5
504 3 thread Serger 14.5
607 Flatseam 24.2
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Bar Tacking
Bar tacking:
§ A reinforcement stitch used in high
stress areas of the garment, or where
there are multiple thickness, to insure
that the seam will not come apart.
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Buttonholes
Standard straight buttonhole:
§ Used on shirts and blouses and
garments made of lighter fabrics
Keyhole buttonhole:
§ Used for heavier fabrics and for
garments that will undergo wash
processes such as acid wash, stone
wash, etc.
§ A keyhole (shown) is made with gimp
and is much stronger than your
standard straight buttonhole
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301 Split Bar Double Needle Lock
Split bar double needle lock:
§ Ideal application:
§ Attaching pockets, it assures
perfect corners
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Button Setting
Button types:
§ 2 Hole: Most commonly used on
shirts and lightweight fabrics
§ 4 Hole: Mostly used on medium
fabrics to heavyweight fabric
§ “X”: A four hole button attached
in an “x” pattern (consumes
more thread than regular 4 hole)
§ Shank button: Set in with a side
attachment, used on a lot of
covered buttons and metal
buttons
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Multi Needle
Multi needle machines:
§ Ideal Applications:
§ Smocking
§ Attaching elastic
§ Waistbands
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Seam Types
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Seam Types/Government Standards
Seam:
§ A series of stitches or stitch types used to join two or more plies of
material together
§ Seams are used for assembling parts in the production of sewn items
§ Seam types for Government standard start with first two letters
describing the seams:
§ Superimposed Seams = SS
§ Bounded Seams = BS
§ Lapped Seams = LS
§ Flat Seams = FS
§ Ornamental Seams = OS
§ Edge finishing Seams = EF
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Superimposed Seams
Superimposed seam (SS)
§ Formed by placing one ply of
material above another with the
edges together and the seam
along one side
§ Most machines can create a
superimposed seam as it is a
very basic seam
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Bound Seams
Bound seam (BS)
§ Made by folding binding
strips or tape over the
edge of the material to
reinforce and finish the
edge
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Lapped Seams
Lapped seam (LS)
§ Formed by overlapping the
material a sufficient
distance and stitching them
together with one or more
rows of sewing
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Flat Seams
Flat seam (FS):
§ Formed by joining two
pieces of materials which
“butt” together but do not
overlap
§ The edges of the material
are cut and aligned during
sewing
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Ornamental Seams
Ornamental seam types (OS):
§ Piping:
§ Uniting a cord or bias trim to a seam
to produce a “piped edge”or corded
effect
§ Fagoting:
§ Uniting with a decorative stitch the
finished edges of two pieces of
fabrics with a space between the
edges
§ Saddle stitch:
§ Done with special machines
§ Blanket stitch:
§ Done with special machines
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Edge Finishing Seams
Edge finishing seams (EF):
§ Picot edge:
§ Looks like a crochet edge but it is
done with a sewing machine that
chains and loops the edge of the
fabric
§ Serged edge:
§ A cut edge of a single ply is
reinforced by overedge stitching to
clean finish and prevent fraying
§ Includes other popular methods of
producing a neat edge like
hemming and blind stitch hemming
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Combination Stitches/Seams
Busted seams:
§ 3/thread overlocking the raw edges of the
seams separately, then single needle lock
stitch or single needle chain stitch join the
seam and press seam open for a flatter
appearance
Ditch stitch/crack stitch:
§ After joining a seam together with binding,
facing, waistband, or a piece of cloth, if you
do not want the stitch to show on the
outside portion of the waistband, you would
stitch right through the “ditch”of the seam as
to create an non-visible stitch
§ Used frequently in contoured waistbands
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Seam Engineering
Characteristics of properly constructed seams:
§ Seam Strength
§ Seam Stretch
§ Seam Durability
§ Seam Security
§ Seam Appearance
Factors that influence all of the above:
§ Stitch Type- the more thread required for a stitch type the stronger the seam.
§ Stitches per inch- the more stitches per inch the stronger the seam.
§ Thread Tensions- Tighter tensions result in weaker seams.
§ Thread type and size- the stronger the thread the stronger the seam.
§ Seam type: Appropriate seaming according to the fabric and process
§ Fabric type/weight- very important in determining seam appearance and durability
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Quality Issues
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Seam Quality Issues
§ Seam puckering
§ Skipped and improper stitches
§ Broken stitches
§ Seam grin
§ Seam slippage
§ Needle damage
§ Needle heat
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Seam Quality Issues
Seam puckering causes:
§ Uneven ply feeding
§ Incorrect thread tensions
§ Incorrect thread or needle size
§ Machine threaded incorrectly
§ Too many stitches per inch
Corrective actions:
§ Ensure presser foot pressure is as light
as possible according to fabric
§ Needle tensions kept low
§ Use finer needles
§ Use low elongation threads
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Skipped Stitches Causes:
§ Timing of looper or hook is incorrect
§ Needle size too big for thread used
§ Needle vibration
§ Needle crooked or bent
§ Loose bobbin
Corrective Actions:
§ Rotate needle slightly so it throws
the needle thread loop into the
looper
§ Check machine setting and thread
tension
§ Try larger needle size
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Seam Quality Issues
Broken stitch causes:
§ Incorrect thread usage (using a low
elongation thread on a knit fabric or
wrong tex size)
§ Harsh after treatments such as
stone washing on heavy denim
jeans (banding appears to be worst
area affected)
Corrective actions:
§ Use of a more flexible thread for the
operation
§ Run loose stitch so stitch rolls rather
than pop during contact with stones
or enzymes
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Seam grin causes:
§ When two pieces of fabric are joined
in a plain seam and strained at right
angles, it may open and reveal a
gap between the two pieces of
fabric.
Corrective Actions:
§ Adjust stitching tensions
§ Increase stitches per inch
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Seam Quality Issues
Seam slippage causes:
§ Slippage occurs when the fabric at
either side of the stitching distorts
and the fabric yarns slide away from
the seam resulting in a permanent
gap within the fabric seam
Corrective Actions:
§ Increase seam allowance
§ Change seam type
§ Increase or decrease SPI depending
on fabric
§ Cut on a bias, where applicable
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Needle Damage causes:
§ When sharp needle point is used the
needle cuts the yarns causing holes
in garment or unraveling
Corrective Actions:
§ Use as fine a needle as possible
§ Ball points are preferred.
§ The ball should be large enough to
spread the yarns apart rather than
sever them
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Do not copy or distribute
Needle Heat
Causes of Needle Heat:
§ Dense fabric
§ Solution: Add fabric softener/lubricant
§ Needle Damaged or Blunt
§ Solution: Change needle, use teflon coated needle.
§ Needle Eye to Small
§ Solution: Use finer thread size
§ Sewing machine is running too fast
§ Solution: Slow down sewing
Gap International Sourcing
Quality Assurance
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62. Confidential Information and Property of Gap Inc.
Do not copy or distribute
Gap International Sourcing
Quality Assurance
62
KhaledAli
Gap QA