Thread classification:
Spun thread is made using natural or synthetic fibres. Spun
polyester is one of the most widely used threads. It is stronger than cotton
threads of a comparable size, and is available in a wide variety of sizes and
colours.
Monofilament thread is made from a single
continuous fibre with a specified thickness. Though monofilament is strong,
uniform and inexpensive to make, it lacks flexibility and is stiff and scratchy
in feel. As a result, usage is normally restricted to hems, draperies, and
upholstered furniture.
Smooth multifilament thread is usually made from nylon or polyester and is used
where high strength is a primary requirement. It consists of two or more
continuous filaments twisted together. It is commonly used to sew shoes,
leather garments, and industrial products
Size - The overall thickness
of the final thread is referred to as ‘Grist’, ‘Ticket Number’, ‘Tex’ or ‘Count’.
Thread should be as fine as possible depending on the required strength of
seam. Generally, thicker threads have greater strength, given the same fibre
content and yarn structure. Finer threads tend to blend into the fabric surface
and are less subject to abrasion than seams with heavier threads. Finer threads
perform better with finer needles and produce less fabric distortion than
heavier needles.
Thread can be classified in different ways. Some common
classifications are those based on:
1. Substrate
2. Construction
3. Finish
1. Classification based on substrate
Natural
The usage of thread made from natural substrates is now
minimal in industry applications. However, the most commonly used natural
thread is cotton thread.
Synthetic
Due to the limitations of natural fibres, thread users have
turned to threads made from synthetic fibres as they have desirable properties
of exceptionally high tenacity, high resistance to abrasion and good resistance
to chemicals. They are also not significantly affected by moisture, rot,
mildew, insects or bacteria.
2. Classification based
on construction thread structure
Spun thread
Spun thread is made using natural or synthetic fibres. Spun
polyester is one of the most widely used threads. It is stronger than cotton
threads of a comparable size, and is available in a wide variety of sizes and
colours.
Corespun thread
Corespun thread is a combination of staple fibres and
filaments. The most commonly used corespun thread has multiple-ply
construction, with each ply consisting of a polyester filament core with cotton
or polyester fibres wrapped around the core.
This thread structure influences the strength of filament
polyester and the sewability of cotton or polyester fibre wrap. Corespun thread
is generally used for the high-speed sewing of many garment types, especially
those requiring high seam strength.
Filament threads
Filament threads are stronger than spun threads of the same
fibre and size. Three types of filament threads are commonly used:
Monofilament thread is made from a single
continuous fibre with a specified thickness. Though monofilament is strong,
uniform and inexpensive to make, it lacks flexibility and is stiff and scratchy
in feel. As a result, usage is normally restricted to hems, draperies, and
upholstered furniture.Smooth multifilament thread is usually made from nylon or polyester and is used
where high strength is a primary requirement. It consists of two or more
continuous filaments twisted together. It is commonly used to sew shoes,
leather garments, and industrial products
Textured filament thread is usually made from
polyester and is used primarily as the looper thread for cover stitches.
Texturing filaments gives the yarn more cover and high extensibility, but makes
the thread more subject to snagging.
Basics of thread
construction
All conventional sewing threads begin their production cycle
as simple yarns. These basic yarns are produced by twisting together relatively
short fibres or fine continuous filaments.
Some terms used in the context of thread construction are:
Twist - The ‘twist’ of a thread refers to the number of turns per
unit length required to hold the fibres / plies together to give the yarn /
thread substance the required strength and flexibility. A thread with an
excessive twist is also likely to give trouble while sewing due to ‘twist
liveliness’, which can cause snarling, loops, knots and possible spillage that
prohibit stitch formation.
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. Direction of twist does not affect the strength of the thread, but
it can seriously impair its performance when it is used on a machine for which
it is not suited.
Ply and cord - Yarns with many components are twisted together to form ply
thread. Most commonly used are 2, 3 or 4 ply threads. Threads are twisted
together to give corded thread. Most commonly used are 4, 6 or 9 cord threads.
3. 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, non wick, anti-fungal, fire
retardant, water repellent and anti-static finishes.