Woven fabrics

1. 6.3. Woven Fabric Construction
The basics of woven fabric consist of two sets of yarns that are perpendicular to each other. The
first set of yarns runs lengthwise through the loom and are set in place prior to weaving. These
yarns are called the WARP yarns. The warp yarns running through the loom can be lifted or left
down on any given cycle of the loom. In weaving any of the basic weave patterns the warp yarns
are lifted or not lifted in specific patterns with each cycle of the loom. When the cycle of the loom
occurs a WEFT yarn is placed across the entire width of the warp yarns. The weft yarn goes under
the warp yarns that are lifted and the above the warp yarns that are left in place creating an
interlacing of the weft yarn amongst the warp yarns.
In the simplest plain weave (also known as a “one by one” or “one over one” weave) every other
warp yarn is lifted on the first cycle of the loom, a weft yarn is placed through the ensuing “tunnel”
known as the shed. At the end of the cycle the yarns that arelifted are lowered and the yarns that
had stayed in position are raised and another weft yarn is placed through the new shed that is
created. These cycles of lifting alternate yarns and placing weft yarns through the created sheds
forms the basis of woven fabric. The patterns of yarns being lifted and left down may vary
according to the weave pattern but the basic concept stays the same for all types of woven fabrics.
A fabric is made up of various elements that define the cloth that has been woven. Those e lements
are included in a fabric construction and fiber description. There are three basic elements of a
fabric construction:
- Thread Counts
- Yarn Sizes
– Weave Pattern
In addition to the three elements of the fabric construction the fiber content (e.g. 100% cotton,
50% cotton/50% linen, 60% cotton/40% polyester) is usually given in the description of a fabric.
In addition, the weight of the fabric is commonly given as a part of the description (either in
ounces per square yard or in grams per square meter).
Thread Counts
The yarn or thread counts give the number of yarns in the warp per linear measurement by the
number of yarns in the weft per linear measurement. The two most common linear measurements
are yarns per inch and yarns per centimeter. A typical 230-thread count down proof cotton fabric
would have a thread count construction of 133 x 100 (in threads per inch). In stating the thread
counts of a fabric, the number of warp yarns are always displayed first followed by the number of
weft yarns. Thus, in our example there would be 133 warp yarns per linear inch in the fabric and
100 weft yarns per lineal inch. The thread count that is sometimes advertised on fabrics is a
summation of the warp yarns per inch and weft yarns per inch (133+100 = 233 thread count).
Thread Counts and Plied Yarns
There has been much discussion over the past few years regarding the proper way to count
threads in a fabric when plied yarns are used in the construction of the fabric. Plied yarns are
created when two or more single yarns are twisted together to form a new yarn that acts as one
yarn in the weaving process. (Diagram 4) All academic sources (textbooks), testing standards
(ASTM testing standards), and industry sources agree that when counting threads that plied yarns
are counted as one thread and not by the number of plies. Thus, in our example the same fabric

2. could be woven with 80’s two ply yarns (80’s two ply would have the same weaving characteristics
as 40 singles).
The proper way to count threads is warp ends (an end is a yarn, single or plied, that is used in the
warp of the loom) and weft picks (a weft pick is a yarn, single or plied, that is used in the weft of
the weaving process). In our example, woven with 80’s two ply yarns (80x2) (sometimes referred
to as 80’s doubles, 80d) the construction would be
133 X 100
80x2 X 80x2
With this construction the thread count remains 233 threads per square inch (133 + 100), only the
yarn size changes to acknowledge the use of two-ply yarns in the construction.
Weave
The third part of the basic fabric construction is the weave. There are three basic weaves and then
many variations of those weaves. The three basic weaves are:
- Plain weave (1 x 1)
- Twill weave (2 x 1)
- Sateen weave (4 x 1)
The determination of what weave to use in a fabric is dependent upon many factors including but
not limited to strength, weight, luster, pattern, and cost. In down proof fabrics, the need to be
tightly woven so as to prevent the migration of down and feathers through the cloth is one of the
primary considerations.
As in most textile decisions there are trade-offs to be considered when determining the weave. The
tightest weave for down proofness is the plain weave. But the plain weave does not have the
softest hand and can feel stiff after finishing. The plain weave does not allow for patterns to be
woven in to the fabric. In determining the weave the end user must prioritize the attributes they
are looking for in a finished cloth to help in the determination of the weave to be used.
Weaving Basics
The weaving loom or weaving machine consists of some basic parts and actions to weave fabric.
(Diagram 5)
Warp Beam – the warp beam is located at the back of the loom and is like a giant spool of thread
that is threaded through the loom as the warp yarns.
Harnesses – the warp yarns are first threaded through vertical wires called heddles that are held
in a frame called a harness. The harness frames go up anddown with the cycles of the loom raising
and lowering the warp yarns in a specific order. When the cycle of the loom is in process there are

3. a set of specific yarns that are raised and a specific set of yarns that remain lowered. When the
yarns are fully raised and lowered the yarns create a shed in which the weft yarn is passed
through.
Shuttle – there are many different ways to pass the weft yarn through the shed, but the
traditional method is by shuttle. As the shed is opened the shuttle is sent across the warp yarns
with the weft yarn. The shuttle is sent across on one cycle and then back again on the next cycle.
More modern weaving machines send weft yarns through the shed by projectiles, rapiers, air (air
jet looms), and water (water jet looms) but the basic idea is still the same.
Reed – the warp yarns are then threaded through a reed, which performs two functions. The reed
keeps the warp yarns separated and pushes the new weft yarn fully forward up against the last
warp yarn to make fabric. The reed has a forward and backward motion after each weft yarn is
passed through the shed, pushing each weft yarn into place in the continual making of fabric.
One cycle of weaving would consist of the harnesses lifting (shedding), the weft yarn being passed
through the shed (picking), and the reed moving the weft yarn into the newly formed fabric
(beating-up) and then returning to its starting position. The next cycle of the loom starts with the
harnesses changing position to create a new shed (the weaving pattern determines the sequence
of harnesses being raised and lowered).
Diagram 5: Drawing of a Simple Loom
Plain Weave
The plain weave is the simplest of all weaves. It is a “one by one” or a “one over one” weave (1 x
1). (Diagram 6) Each weft yarn in a plain weave goes over one warp yarn and then under the next
warp yarn, alternating every other yarn as it passes through the loom. On the next cycle of the
loom, the next weft yarn starts under the first warp yarn and then goes over the next warp yarn.
There is only a need for two harnesses in a plain weave. The first harness contains the odd
numbered warp yarns and the second harness contains the even numbered warp yarns. Thus, half

4. of the warp yarns are in the upper part of the shed on one cycle and the other half of the warp
yarns are in the upper position on the next cycle.
Diagram 6: Drawing of a plain (1x1) weave
a) Favorable attributes of a plain weave
- For a given yarn size, the plain weave produces the lightest weight fabric.
- Plain weaves tend to wear well (abrasion resistance).
- For down proof fabrics the plain weave is the tightest w eave as the warp and weft yarns have the
least amount of space between the yarns.
- The surface is smooth, offering a good surface for printing.
b) Unfavorable attributes of a plain weave
- Plain weaves tend to wrinkle more than other weaves
- No woven patterns can be made in a plain weave
- The tear strength is lower in a plain weave than in other weaves.
Twill Weave
Definitions:
Interlace – the place where one yarn intersects another yarn by crossing over it or by going under
it (depending on which way you look at the fabric).

5. Float – The section of a weft yarn that goes over more than one warp yarn (or the section of a
warp yarn that goes over more than weft yarn).
The characteristic of a twill weave is diagonal lines woven into the fabric. There are many ways to
weave diagonal lines but the most common weave is a 2 x 1 (two by one) weave. (Diagram 7) The
twill weave is woven in a pattern that creates diagonal lines by having interlaces run diagonally in
the weaving pattern. The pattern can run up to the right (a right hand twill) or up to the left (a left
hand twill). As an example a woven herringbone pattern alternates between a right hand twill
weave and a left hand twill weave.
Diagram 7: Drawing of a twill weave
Notice that the weft (white) yarns go under two and over one and that the interlaces (the exposed
white weft yarns crossing over the warp yarns) are in a diagonal pattern moving up to the right
(this is a right hand twill pattern).
In order to weave a basic 2 x 1 twill weave the loom must have a minimum of three harnesses that
lift in a specific order. The weaving pattern is complete after three weft yarns are inserted and then
starts over again. In a twill weave the weft yarns are not interlaced with every other warp yarn,
which creates a float. Because of the floats the twill weave allows more of the same size yarns to
be woven in a square unit (e.g. square inch, square centimeter) than in a plain weave. Using the
same size yarns a twill weave thus, would have more yarns per square unit and b e heavier than a
plain weave fabric.
Twill weaves can come in many different constructions such as 3 x 1, 4 x 1, 3 x 2, or 4 x 2 (there
are others – these are just examples). The characteristic of all twill weaves is the diagonal lines
woven into the fabric called twill lines.

6. Twill weaves are known for their strength and durability. The most common twill weave is denim.
Fabrics woven with a twill weave are stronger, heavier, and more durable than those using the
same yarns sizes woven with a plain weave.
Sateen Weave
A Sateen Weave is a 4 x 1(four by one) sateen. The sateen weave has longer floats and the
interlaces are put in a pattern such that they do not touch and thus do not form twill lines. If you
have a set of numbers that you want to put in an order such that no two numbers will be
consecutive, even in an on-going repeat of the numbers, the number five is the smallest number
this can be accomplished with. The pattern would be something like 1-3-5-2-4 and then it would
repeat 1-3-5-2-4-1-3-5-2-4. As you see, none of the numbers in order and in repeat are
consecutive numbers. This concept is important in a sateen weave because breaking up the places
where the interlaces are located in a weaving pattern prevents twill lines from being formed.
The sateen weave can be woven as a warp sateen, meaning the warp yarns are the floats on the
face of the fabric or as a weft sateen, meaning the weft yarns are the floats on the face of the
fabric
At the sateen weave, there are no interlaces touching in the weave. You can also observe the long
floats that exist in a sateen weave. In the same way that the floats in a twill weave allow for more
yarns of the same size to be inserted in relation to a plain weave, the longer floats of the sateen
weave allow for more of the same size yarns to be inserted in relation to a plain weave or a simple
(2 x 1) twill weave.
a) Favorable attributes of a sateen weave:
- Softer hand
- Better drape
b) Unfavorable attributes of a sateen weave:
- Will not hold a down proof finish as long other weaves
- Heavier in weight than a plain weave or a twill weave woven from the same yarn size.
Thread count versus weave versus fabric weight – Some Considerations
If having the highest thread count possible in a fabric is the goal, then a sateen weave would allow
the most threads per square unit and would be the weave of choice.
If having the tightest weave to make the fabric down proof is the goal, then a plain weave would
be the weave of choice.
If having the lightest weight fabric for a given yarn size is the goal, then a plain weave would be
the weave of choice.
If having the strongest fabric is the goal, then a twill weave would be the weave of choice.
If having the softest hand in the finished fabric is the goal, then a sateen weave would be the
weave of choice.

7. As you can see, there is not an ultimate fabric for down proof cloth. You must be able to prioritize
your goals and understand that when you gain one attribute you may well be giving up another.
With regards to thread count let’s look at an example.
A common down proof fabric used in the industry is a plain weave using sixty singles (60s) yarns.
The construction of this fabric is as follows:
140 x 140
60s x 60s
1 x 1
Weaving in a plain weave we have 280 threads per square inch.
If we take the same 60s yarns and weave a sateen weave, we are able to insert many more yarns.
A common down proof construction for a sateen weave using 60s yarns is as follows:
173 x 150
60s x 60s
4 x 1
Weaving in a sateen weave we have 323 threads per square inch. That is a difference of 43
additional yarns per square inch, a 15.4% increase in thread count just by changing the weave.