Yarn manufacturing
Yarn properties and sewing threads
ጥር/2015 ዓ/ም
By Tekalgn M. October/2022 G.C.
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Sewing threads
• Sewing threads are special kinds of yarns that
are engineered and designed to pass through a
sewing machine (needle) rapidly.
• They 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.
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Factors that affect functions of a sewing
Aesthetic Characteristics
• Fineness, color and luster must be taken into account for decorative
purposes
• Other considerations
• Hue and shade
• Color fastness
• Stitch selection
• Even stitch formation
Performance of Sewing Thread
• should be durable to withstand the
• Abrasion during wearing
• needle heat that occurs while sewing,
• finishing of garments and during wear.
• Sewing thread performance could be assessed
from its:
• Seam strength, Abrasion resistance, Elasticity, Chemical resistance, Flammability, Color
fastness 3
Basic Requirement of Sewing Thread
Sew-ability
• Sew-ability is a capability of sewing thread to produce a seam with a minimum
sewing thread breakages and
• the minimum damage to the thread and the fabric during the stitching process.
• The parameters that determine sew-ability of thread are
• No breakages in high-speed sewing
• Consistent stitch formation
• No skipped stitches
• Evenness, to prevent changes in tension during sewing
• A high level of abrasion resistance 4
• Sufficient surface smoothness, to pass easily through the machine guides
Thread Performance in Seam
• It is the capacity of a thread to produce the desired functional serviceability in
a desired seam
𝑆𝑒𝑎𝑚 𝑇𝑒𝑛𝑠𝑖𝑙𝑒 𝑆𝑡𝑟𝑒𝑛𝑔𝑡ℎ
Seam Efficiency Index (SEI) = ∗ 100
𝑓𝑎𝑏𝑟𝑖𝑐 𝑡𝑒𝑛𝑠𝑖𝑙𝑒 𝑠𝑡𝑟𝑒𝑛𝑔𝑡ℎ
Properties of Sewing Thread
• Good tensile strength
• To grip the seam firmly during wash and wear.
• The thread strength should be higher than the fabric so it will not
rupture during wear
• Higher initial modulus
• to have least thread deformation during shock loading in sewing.
• The sewing thread should be moderately stiff to form the loops
for stitch formation.
• Smooth surface and negligible faults
• To minimize friction between the needle and sewing thread while 5
sewing at high speed.
• It should be adequately lubricated to improve the abrasion
resistance and its sewability.
• Uniform thickness
• To have smooth passage of thread through the needle and the
fabric.
Properties of Sewing Thread
• Good elasticity
• Facilitates the thread to recover its original length instantly after the
tension has been released.
• The elastic property of thread influences the strength and quality of a
stitched seam.
• Good colour uniformity and fastness
• Resistance to the various chemical agents the thread is exposed to during
garment manufacturing and washing.
• The thread should be dyed evenly and uniformly.
• could maintain the original colour of sewing thread without any fading while it is
exposed to washing and sunlight.
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• Lower shrinkage
• characteristics of the thread comparable to the fabric shrinkage to avoid
shrinkage puckering on garments.
• Cotton threads usually undergo washing shrinkage puckering while synthetic
threads suffer from the thermal shrinkage during ironing.
• Better chemical resistance
• is an enviable characteristic for sewing thread in garments that could
undergo washing, bleaching or drycleaning during wear.
Properties of Sewing Thread
• Higher abrasion resistance
• provides a good sewing performance and
makes the thread more durable.
• Minimum metamerism
• could be attained by the measurement of thread colour with
colour matching cabinets.
• Metamerism is an intrinsic characteristic of a thread when the 7
same thread colour appears to be dissimilar under diverse
lighting conditions.
Classification of Sewing Thread
1. Classification Based on Substrate
• Natural:
• Natural fibres made sewing thread is very rare in
industrial applications
• cotton is the most frequently used natural sewing
thread
• Synthetic:
• They have several advantageous characteristics over
natural fibres such as:
• high tenacity, better resistance to chemicals and 8
higher abrasion resistance.
• Further, they are also not considerably influenced by
rot, mildew, insects, bacteria and moisture
2. Classification Based on Thread Construction
Core-spun thread
Spun thread
• It is a combination of staple fibers and filaments
• Spun thread is made using natural or
• core spun thread has multiple-ply construction,
synthetic fibers.
• with each ply consisting of a polyester filament core with cotton or
• Spun polyester is one of the most widely used polyester fibers wrapped around the core.
threads. • This thread structure influences the strength of filament
• It is stronger than cotton threads of a polyester and the
comparable size, and is available in a wide sew-ability of cotton or polyester fiber wrap.
variety of sizes and colors. • It is used for the high-speed sewing of many garment
types, especially those
requiring high seam strength.
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Conti…
Filament threads
• Filament threads are stronger than spun threads of the same fiber and size.
• Three types of filament threads are commonly used:
Smooth multifilament thread
Monofilament thread
• usually made from nylon or polyester
• It is made from a single continuous fibre with a
specified thickness. • used where high strength is a primary requirement.
• It is strong, uniform and inexpensive to make, rigid • consists of two or more continuous filaments twisted
and rough in feel. together.
• Because of this limitation, it is limited to sewing of • commonly used to sew shoes, leather garments, and
hems, draperies and upholstered furniture industrial products.
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Conti…
Textured filament thread Embroidery Threads
• Texturization enhances texture to the continuous filament • Mainly required for decorative purposes
yarns by providing softness and bulk. • Colour and lustre are two main requirements for
embroidery threads
• They are then slightly twisted and heat set to make it
permanent. • Mostly made from mercerised cotton, silk, viscose
rayon and polyester fibre/filament yarns
• usually made from polyester and is used primarily as the
looper thread for cover stitches.
• They gives the yarn more cover and high extensibility, but
makes the thread more subject to snagging.
Technical Threads
• Specifically developed for technical/industrial uses
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• Perform satisfactorily in adverse climatic, industrial
conditions and
heavy duty applications
• Generally made from aramids, glass, ceramics, etc.
Basics of thread construction
• All sewing threads begin production cycle as simple yarns.
• produced by twisting together these simple yarns
• Some terms used in the context of thread construction are:
• Twist
• refers to the number of turns per unit length required to hold the
fibers / plies together to give the yarn /
• thread substance the required strength and flexibility. 12
• A thread with an excessive twist can cause to trouble by forming
• snarling, loops, knots and possible spillage that prohibit stitch
formation.
Conti…
• Twist direction
• Direction of twist is identified as ‘S’ for left twist and ‘Z’ for right twist.
• Most single needle lock stitch and other machines are designed for ‘Z’
twist threads.
• ‘S’ twist thread untwists during stitch formation.
• Twist direction does not affect the strength of the thread,
• But it can impair its performance when it is used on a machine for which it is
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not suited.
Classification based on thread finish
Finishes are given to a thread for two purposes
• To improve sewability
• Some finishes involve increasing strength, abrasion resistance and lubrication of the
thread.
• To achieve a specific functional requirement
• Some finishes include bonding, anti-fungal, fire retardant, water repellent and anti-
static finishes.
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Sewing Thread Size
• It is significant factor in accomplishing the functional and aesthetic
requirements of the finished garment.
• Sewing thread sizes could be expressed
• Direct system (tex, decitex)
• Filament sewing threads are generally expressed in denier or
decitex
• Resultant thread size = Single yarn count/Number of plies
• Indirect system
• Metric system (Nm)
• used to express synthetic, spun and core spun thread size
• English system (Ne) 15
• used to express the size of cotton thread
• Resultant thread size = Single yarn count × Number of plies
Cont…
Ticket Numbering
• This is the number of meters of thread per gram.
• is a commercial sewing thread numbering method for expressing the sewing
thread size
• The metric system, English system and Denier systems are generally used to
arrive at the ticket number of the finished sewing thread.
• A value of a ticket number in one type of sewing thread will not be the same
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as in another.
• For example, Ticket 40 cotton is not the same as Ticket 40 core spun
thread.
Cont…
Ticket Numbering (Conti..)
• Generally, the higher the ticket number, the finer the thread and
vice versa
E.g. one gram of single ply thread is 60m
• For Cotton Sewing Threads long. (60/1)
NB:
𝑠𝑖𝑛𝑔𝑙𝑒 𝑦𝑎𝑟𝑛 𝑒𝑛𝑔𝑙𝑖𝑠ℎ 𝑐𝑜𝑢𝑛𝑡(𝑁𝑒) ∗3 • numerator = length of yarn
• Cotton ticket number = • Denominator =number plies
𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑝𝑙𝑦
Calculate
• For Synthetic Sewing Threads Metric number of Metric ticket
17 thread (Nm) number of thread (Tkt.
No.)
𝑠𝑖𝑛𝑔𝑙𝑒 𝑦𝑎𝑟𝑛 𝑚𝑒𝑡𝑟𝑖𝑐 𝑐𝑜𝑢𝑛𝑡(𝑁𝑚) ∗ 3 80/2 120
metric ticket number =
𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑝𝑙𝑦
80/4 60
• Ticket number =resultant count *3 60/1 180
60/2 90
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