2. Khulna University of Engineering
& Technology
Prepared by,
Md. Razib Sheikh
ID. 1221025
Final Year Student
Department Of Textile Engineering, KUET.
3. Seam
• The line along which a number of layers of fabrics are
joined is called the seam. Seam can be created in
sewing of fabrics or by joining of fabrics in any other
alternative way(Welding, Fusing, Moulding, Adhesive).
• In other words, Seam is the combination of stitch
which makes line to join two ply of fabric.
• The seam which is created by sewing of fabrics, known
as stitched seam.
• Seam is used as functional purpose(e.g. strength,
security etc.). Sometimes used as decorative purpose.
4. Seam Characteristics
Seam strength: Seam strength should be equal to or a little
bit lower than the strength of the fabric in both direction.
Elasticity: The elasticity of seams should be equal to or
greater than the elasticity of the fabric.
Durability: The Durability of seam should be equal to
duration of the use of the garment.
Security: During the wearing of the garment there should
have guarantee so the for normal reasons the will not be
opened due to the opening or breaking of the thread.
Comfort: The seam of some garment( e.g. underwear,
undergarment) should have comfort feel.
Some special characteristics e.g. water proof of seam
should have, as for required garments.
5. Seam Quality Parameters
Though the stitch types chosen for a seam depend on the
functional or aesthetic requirements of the seam, seam
quality can be measured based on the following parameters:
1. Seam size:
It is measured with seam depth, seam length and seam
width.
2. Seam slippage strength:
It is the amount of force required to pull out a total of ¼”
of the opposing sets of yarns perpendicular to the seam
line.
3. Seam strength:
It is the force required to break open the seam either by
breaking the thread or by breaking the sewn material.
6. Seam classes
According to BS 3870-1:1991, the eight
seam classes are following:
• Class 1 – Superimposed seam.
• Class 2 – Lapped seam.
• Class 3 – Bound seam.
• Class 4 – Flat seam.
• Class 5 – Decorative/Ornamental seam
• Class 6 – Edge finishing/neatening seam.
• Class 7 – Applied seam.
• Class 8 – Others. Fig: Different types of seam
7. Class 1 – Superimposed seam
• This is the most common & mostly used
seam for joining fabrics. In this seam, two
plies of fabric are placed on one another
perfectly & then the fabrics are sewn.
• Most commonly used.
• The sewn edges of the fabrics remain in
the same side.
• It has over 50 variations.
• This class of seam can be sewn a variety
of m/c. e.g. Lock stitch, overlock
machine.
Uses:
• Mostly used in inside seam like as shirts,
pants, trousers & children wears .
Fig: Class 1 – Superimposed seam
8. Class 2 – lapped seam
• This type of seam is achieved with two or
more pieces of fabric over lapping each
other.
• Two sewn ends of the fabric are in
opposite direction.
• Mostly two needle chain stitch m/c is
used.
• Seam under this class is very strong.
• At least two line of stitching are used.
Uses:
• This class of seam is not mostly used for
sewing garments. This seam is used in
sewing jeans pants, lunges etc.
Fig: Class 2- lapped seam
9. Class 3 – Bound seam
• A bound seam is one piece of fabric
encompassing the raw edge of another
piece of fabric. This produces a neat edge
on a seam exposed to view or to wear.
• The purpose of bound seam is to finish an
edge of garment.
• Some time used as decorative purpose.
• The binder fabric may be different colors.
• There are 18 variation of bound seam.
Uses:
• Used in sewing men’s underwear, pants,
sleeping suits, Neckline of a T-shirt, yoke
joint in the shirt waist band.
Fig: Class 3 – Bound seam
10. Class 4 – Flat seam
• Flat seam are constructed by
having two pieces of fabric meet
precisely at their edges.
• Seam thickness is comparatively
less.
• Zigzag stitch may be produced.
• Edge should be cleaned before
sewing to avoid fraying.
Uses:
• This seam is widely used in
under garments & in knitted
items.
Fig: Class 4 - flat seam
11. Class 5 – Decorative/Ornamental Seam
• This type of seam is made by making
one or more adjacent stitch lines in one
or more layer of fabric. The fabric which
we used that would be folded in several
times and then according to the under
side of the folded part of the fabric stitch
can be produced.
• This seam type consists of a minimum of
one component.
• Multi needle sewing m/c is used.-
• Seam under this class are produced only
for decorative purpose.
Uses:
• Used in pant or other dresses, Cartains,
Table cloths, Furniture wears, Decorative
ladies wears etc.
Fig: Class 5 – Decorative/Ornamental Seam
12. Class 6 – Edge neatening seam
• The seam of class-6- is called edge
neatening which is used to holds the edge
of the fabric such that the yarns of the
fabric can not open easily.
• All the over Lock stitch is edge neatening
class seam.
• It can be made by overlock m/c.-
• Extensively used.
Uses:
• Mostly used knitted garments and
hemming.
• To protect the fabric edge such that
the warp yarn of the fabric can not easily
open.
• Serging trouser panels, flys, facings, etc.
Fig: Class 6-Edge neatening
13. Class 7 – Applied Seam
• This seam class involves seams that
require the addition of another
component onto the edge of a piece of
fabric e.g., elastic braid onto the edge
of ladies briefs. This type of seam
requires two components.
• They are mainly used to a decorative
material to an edge of seam such as
lace-elastic.
• Similar to lapped (class-2) but the
joined component is extended limited
on both sides from sewn line.
Uses:
• Joining of lace, elastic braid to shirts of
young people, ladies briefs etc.
Joining of lace
Joining of elastic braid
Fig: Class 7 – Applied Seam
14. Class 8 – Others
• This seam class consists of
one piece of fabric that is
turned in on both edges.
The edge of fabric is sewn
by folding in various ways.
• It is most commonly seen
in belt loops or bets for
which a folder can be
attached to the machine.
This type of seam requires
only one component.
Fig: Seam class 8
