The document discusses sewing threads and their manufacturing process. It defines sewing threads and their various uses in garments, upholstery, and other fabrics. It then describes the different types of fibers used - including cotton, polyester, rayon, nylon and metallics - and their characteristics. Next, it discusses factors that influence the cost of sewing threads. It concludes by outlining the functions of various machines used in the sewing thread manufacturing process and different types of winding systems.

1. Sewing Threads
Sewing Thread:
Sewing threads form efficient stitches without breaking or becoming distorted during the
useful life of the product. The basic function of a thread is to deliver aesthetics and
performance in stitches and seams.
According to the definition given by ASTM, sewing thread is a flexible, small diameter yarn
or strand usually treated with a surface coating, lubricant or both, intended to be used to
stitch one or more pieces of material or an object to a material. It may be defined as
smooth, evenly spun, hard-twisted ply yarn, treated by a special finishing process to make it
resistant to stresses in its passage through the eye of a needle and through material
involved in seaming and stitching operations1.
Sewing threads are used in garments, upholstery, air-supported fabric structures and
geotextiles to join different components by forming a seam. The primary function of a seam
is to provide uniform stress transfer from one piece of fabric to another, thus preserving the
overall integrity of the fabric assembly.
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2. Costing of Sewing Threads
It would depend upon the following factors
1. Fibre Composition i.e. polyester, spun polyester, cotton, nylon, etc
2. Number of filaments i.e. mono, multiple,etc
3. count of the threadi.e. higher the more it is finer and therefore more the cost.
4. processing i.e. whether it is singeid or how it has been winded or some special
lubrication is done, etc
5. finishing i.e. how it has been finished depending upon the fibre composition and end
use
6. packaging size i.e. in which thing it has been rolled depending upon the end use, i.e.
cop, or spool or cone, etc. and what is the diameter of the material, as diameter
increase, cost also increases as longer length of thread is required.
Cost Breakup
Fibers – It cost around 50% of the total cost
Processing - It cost around 18% - 20% of the total cost
Finishing - It cost around 20 – 25% of the total cost
Package Size - It cost around 10% – 12% of the total cost
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3. Different Types of fibres
Rayon
Produced by pressing cellulose acetate through small holes and solidifying it in the form of
filaments.The rayon thread size can be expressed as Tex 25.
Characteristics of rayon:
high sheen
soft, and works well in detail
relatively heat resistant
not colorfast
not as strong as polyester
less durable than polyester
Polyester
Synthetically produced by pressing polymer resins through small holes and solidifying in the
form of filaments. Thepolyster thread size can be expressed as Tex 25
Characteristics of polyester:
durable. designed for heavy duty use
stronger, more tensile strength than rayon
colorfast
retains shape
recovers stretch
spun poly is strong, with a matte appearance
trilobal poly has a sheen equal to rayon but is not as strong as spun poly.
Nylon
A synthetic thread most commonly in the form as a monofilament clear thread or as a
texturized fuzzy thread.The Nylon thread size can be expressed as Tex 70
Characteristics of nylon:
strong
low melting temperature. not heat resistant.
notcolorfast. will yellow over time.
becomes brittle through laundering
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4. Cotton
The only 100% natural fiber thread made for high speed machines. Cotton has various
finishes, each providing specific results.
Mercerized The thread is treated is a solution, causing the fibers to swell. This allows the
dye to better penetrate the fibers and increases the luster of the thread. It also increases
the strength of the thread.
Gassed The thread is passed through a flame at high speed to reduce the fuzz.
Glazed The thread is treated with wax or other chemicals, them polished to create a
higher luster. Although the result is a glossy, hard finish which protects the thread, the
glaze does rub off and can gum up the needle and machine.
The cotton thread size can be expressed as Tex 40 or T-40.
Characteristics of cotton thread:
soft
strong and durable
easily adjusts to changes in the fabric (such as shrinkage) since it is a natural fiber
available in various thread weights
easy care
Metallics
The quality of metallic thread ranges from very high to very low. A good metallic thread
does not require a lubricant. Quality metallic thread has the following components:
Nylon core. A nylon core offers the most strength. Polyester and rayon cores are
inferior.
Rice paper construction. This adds strength and cohesiveness and makes the thread
more soft and supple, reducing the wiry feel. It also reduces tangling.
Outer coating. Lower end metallics have no outer coating. This means the metal foil
rubs against the needle, creating friction, resulting in discoloring and shredding. A
good metallic has an outer coating which reduces friction and acts as a protective
layer.
Laminate or Flat thread. Produced by bonding layers of polyester together and
slicing to a desired width. Usually available in either 2 ply or 5 ply.
colorfast
brilliant, reflective, colors
heat resistant. can be ironed
5 ply does not require special handling for good results. 2 ply usually requires special
handling for good results.
able to produce in a hologram effect
Smaller Tex numbers indicate fine thread, and a larger number signifies a thicker
thread. Metallic threads usually falling in the range of Tex 12 to Tex 50.
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5. Different types of filament Threads
Monofilament Threads:
Monofilament is not a conventional thread, as it comprises only a single
filament, suitably lubricated. Monofilaments are produced by melt spinning (as are
continuous multifilament yarns), but the spinneret has only one aperture which is
much larger than for conventional yarns.
Multifilament Threads:
Plied or corded threads produced from 100% synthetic (polyamide or
polyester) filaments are used as continuous filament threads. Where flexible threads
are required, the filaments are twisted, set, dyed and lubricated only. Where optimum
sewing performance and abrasion resistance are required, the plied threads are treated
with synthetic co-polymer, which bonds the individual filaments together. Plied
continuous filament multilobal polyester threads are favored for embroidery
applications on account of its superior lusture.
Very fine threads are produced from a single ply of multifilament polyester
yarn, suitably twisted and then treated with a light bonding finish - just sufficient to
consolidate the individual filaments without stiffening the final product.
Silk Threads:
Although they are not widely used, some sewing threads are made from spun
silk. An important feature of such yarns is the high extent at break of about 20%, along
with a high breaking load. Some continuous filament silk yarns are used for
buttonholes and decorative stitching because of their attractive appearance and
smoothness.
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6. Plys
The number of component yarns that are twisted together to produce a thread is the ply.
Two-plythreads, therefore, are simply two yarns which havebeen twisted together.
Thread Size Comparison
Heavy weight threads: Tex 40 - Tex 90
Medium weight threads: Tex 27 - Tex 35
Light weight threads: Tex 10 - Tex 24
Tex - This is the weight in grams of 1,000
meters. (1 Tex = 1 gram per 1,000 meters)
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7. Sewing applications by thread size:
Fine tex(18-30)
Blouse
Dress
Lingerie
Sleepwear
Swimwear
Other light articles
Medium Tex (30-60)
Aprons
Athelatic Wear
Caps
Coats
Draperies
Foundation Garments
Jeans
Rain wear
Pants
Shorts
Wind Breakers
Heavy Tex (60-105)
Foot Wear
Golf Bags
Luggafe
Over Coats
Parkas
Protective Clothing
Work Wear
Extra Heavy Tex (105-135)
Decorative Stitching
Bold Design Looks
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8. Functions of various machines in sewing thread
manufacturing process
Yarn singeing
Sewing thread must be singed to ensure that the projecting fibres do not interfere with downstream
processing. Percentage of singeing can be achieved varied by varying the yarn collection speed. Hair
removal efficiency at singeing machine is normally 30 - 50%. Flame temperature is around 800 oC.
Singeing is mainly done in Cotton Sewing Threads.
Features
• The heart of the machine - the burner, serves to singe reliably the projecting fibres of yarn running
through at high speed, without inflicting burns on yarn itself. There is a choice between the gas
burner and the electric burner. Gas burner are widely used. The gas burner consumes about 55 gm
of natural, propane or butane gas an hour, depending on singeing rate and yarn type.
• Speed: 300-1200 m/min.
Hank to cone winding
• Conversion of hank in to cone of suitable weight
• Waxing for reducing co-officient of friction in sewing thread .
Features of new machines:
• Twin Input Rollers: At the front of the head are the twin-input rollers, set to a fixed speed
but proportional to the winding speed. The main functions of this unit are to eliminate
unwanted tensions prior to yarn entering waxing unit.
• The speed of machine ranging from 400-700 mpm, with possible traverse from150-200
mm.
Polishing
Some threads for special end uses like leather industries, bag stitching, kite flying are
treated with starch, softeners, whitener, etc on this machine. Cooked starch is mixed with
other chemicals and different recipes are made for different qualities depending on the end
uses.
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9. Main objectives of polishing are:
• Extra ordinary smooth surface
• Thread becomes round.
• Stiffness increases.
• Increase in tensile strength (7-10%).
Cross winding and lubrication
• Winding in various types of sewing thread packages like cone, cop , tube, ball, vicone and
spool.
• Threads are treated with special waxes for achieving best workability during sewing
operation.
• Lick roller lubrication is applied on industrial sewing thread where thread has to run on
high speed sewing machine; the basic ingredient of the most of the lubricants is parafin wax.
Although silicones are also used because of their stability to heat and various additives are
also included to give some special properties.
Geometry of packages
Threads are wound in many forms. Small length spools are employed in retail store
distribution, whereas somewhat larger spools are used to a limited extent industrially. Some
of the very fine soft threads are wound on cones, very coarse soft threads are in skein form,
but the largest proportion by far is wound on the one headed tube with base or straight
tubes. These packages in some instances are put on a weight basis; however, the larger
percentage is marked on a length basis. Ready-wound bobbins in a number of styles to
accommodate the various sewing machines employed are also available. Cross winding
threads are generally laid in with traverse ratio 1: 6 (one double traverse = six spindle
revolution) and 1: 4 for coarser counts.
The following types of packages are used in sewing threads (with commonly used
dimensions).
Spool: Spools are small flanged plastic or wooden bobbins, they are both with tapered (so-
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10. called Diabolo spools) and straight flanges. Mainly parallel winding (because side unwinding
is easy) is done. Cross-windings are also possible on the spools. They contain relatively short
length of 100-500 meter thread. The length of traverse on spool is 2.9-3.8 cm.
End uses: Upholstery, footwear, leather goods manufacturing, and in hand sewing
operations.
Cop
Cops are small cylindrical flangeless spools, with precision cross winding. They are mostly
made of paper and plastic. They are of two types, small Cop (Tube) and medium Cop (Cop).
The lack of flanges facilitates regular off winding on industrial sewing machines although
their small diameter makes them less well suited to the faster thread take off machines.
Smaller Cops are popular make-up in fashion trades, where a variety of shades are used and
production runs for any one colour or style of garments. The length of thread wound ranges
from 100-2000 m on small cop and 400-4000 m on cop. The length of traverse on small cop
is 5 - 6.3 cm and on cop is10 cm.
End uses: Kite flying, Upholstery, ready-made garment, tailoring, hosiery, umbrella, and
shoe stitching
Cone: This is self-supporting, cross wound conical package. It is easier to withdraw yarn over
end from a cone than from a cheese and because of this, cone is more widely used. They
contain relatively long lengths 1000-25000 m with length of traverse ranging from 10-15 cm.
They give trouble free thread unwinding at intermittent or continuous high speeds. Cones
are the most economical packages for conventional sewing threads in situations where
thread consumption is high and production runs are long.
End uses: ready made garment, tailoring, hosiery, leather stitching, Upholstery, shoe
stitching, denim, embroidery, and kite flying.
Vicone or King Spool: Vicones are parallel tubes or low angled cones with an additional base
in the form of a raised flange, which may incorporate a small tip. The build of vicone
depends on the exact conformity of the taper with the angle of vicone’s base. Coarse yarns
require a large traverse for the taper -- fine yarn a small one. They contain lengths of 1000-
5000 m with length of traverse 6.5-9 cm.
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11. End uses: embroidery, core-spun, and filament threads .
PrewoundBobbin:Prewound bobbins are precision parallel wound thread package designed
to replace metal bobbins on a variety of lock stitch machines.
Skein: A very small hank of soft twisted plied thread (around 8 m) of coarse count, is parallel
wound with the help rotating flyer, which withdraws the thread from the supply package
cone.
End uses: embroidery.
Ball: A typical ball like structure, wound with the help of four types of different winding.
They are: Rough base winding, form winding, surface layer winding, and circumference
winding. The initial winding provides firmness at the base. Next winding process makes
space for placing the identification ticket. The third stage of winding provides firm gripping
of the ticket. The last stage of winding makes a band over the ball, which retains its shape.
An easy unwinding of thread is possible.
End uses: embroidery, fishing net and bag closing.
Cocoon: Cocoons are self-supporting i.e. center-less thread package specially designed for
the insertion in the shuttle of multi needle quilting and some types of embroidery. Cocoons
are used in the shuttle of multi needle quilting and some types of embroidery machines.
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12. Different types of winding system
Precision winding:
• Constant winding ratio
• Winding angle reduces with increasing diameter
• No pattern areas
• Good off-winding characteristics
• High package density
Step precision or digicone winding:
• Almost constant winding angle
• The wind ratio is reduced in steps
• Combines the advantage of random and precision winding
• No pattern areas
• Higher consistent package density
• Perfect unwinding characteristics
• Straight sided packages
Random winding:
• Winding angle is kept constant since the winding ratio reduces with increasing diameter
• Stable packages
• Even density
Pineapple winding:
• Winding traverse reduces to produce packages with tapered edges
• Required for filament winding operations
• All three types of winding applicable
Parallel winding:
• Very high package density
• Thread vertical to package axis
• Relatively short lengths of thread
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13. • Suitable for side unwinding
• No pattern areas 5,6
Ball winding:
• Very easy unwinding
• Winding takes place in 4 stages:
1. Rough base winding
2. Form winding
3. Surface layer winding
4.Circumferencial winding
Skein winding:
• Easy unwinding
• Very small parallel strand of soft twisted thread.
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14. Different types of coating
Bonded:
Polyester or nylon thread coated to keep it from shredding and to reduce abrasion.
Gassed:
Cotton thread quickly passed through a flame to reduce fuzz.
Glazed (glacé):
Cotton thread for hand-sewing, treated with starches, waxes, or chemicals, and polished to
a luster for a smooth, glossy surface to reduce knots and tangling. This finish can gum-up a
sewing machine.
Mercerized:
Cotton or cotton-covered polyester thread given a caustic soda bath that’s neutralized with
an acid bath. Mercerizing adds strength,luster, and dye affinity, and reduces lint.
Soft:
Usually refers to a cotton thread to which no finishing processes have been applied
Silicone/Hot Wax
Done to spun polyester
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