Jeans Manufacturing

Muhammad Ahmed
Muhammad AhmedDawood University of Engineering & Technology
Jeans Manufacturing
Raw Material
True blue jeans are made out of 100 percent cotton, including the threads. Polyester blends are available,
however, the over-whelming majority of jeans sold are 100 percent cotton.
The most common dye used is synthetic indigo.
The belt loops, waistband, back panel, pockets, and leggings of a pair of blue jeans are all made of indigo-dyed denim.
Other features of blue jeans include the zipper, buttons, rivets, and label.
Rivets have been traditionally made of copper, but the zippers, snaps and buttons are usually steel.
Designers' labels are often tags made out of cloth, leather, or plastic, while others are embroidered on with cotton thread.
Jeans Manufacturing
Jeans Manufacturing
Weaving theYarn:
• The yarn is then woven on large mechanical looms. Denim is not 100 percent blue, as the blue dyed
threads forming the warp (long, vertical threads) are combined with white threads forming
the weft (shorter, horizontal threads). Because denim is woven with the blue threads packed closer
together than the white threads and with the blue threads covering three out of four white threads,
the blue threads dominate. (By examining a piece of denim closely one can detect the steep diagonal
pattern that results from this process, which is known as a three-by-one right-hand twill weave.)
Although mechanized looms make use of the same basic weaving procedure as a simple hand loom,
they are much larger and faster. A modern "shuttle-less" loom (which uses a very small carrier instead
of the traditional shuttle to weave the weft threads between the warp threads) may produce as much
as 3,279 yards (3,000 meters) of cloth 3.28 or 4.37 yards (three or four meters) wide in a single week.
As much as 1,093 yards (1,000 meters) of cloth may be rolled into a single huge bolt.
• At this point the denim is ready for finishing, a term referring to a variety of treatments applied to
cloth after it is woven. With denim, finishing is usually fairly simple.The cloth is brushed to remove
loose threads and lint, and the denim is usually skewed in a way that will prevent it from twisting
when it is made into clothing.The denim may then be sanforized, or preshrunk. Preshrunk denim
should shrink no more than three percent after three washings.
Jeans Manufacturing
Cutting Of jeans:
Once the desired design is selected, patterns from the design are cut from heavy
paper or cardboard. Up to 80 different sizes are possible from one pattern. The
pieces of denim are then cut with high speed cutting machines from stacks 100
layers thick. Excluding rivets, buttons, and zippers, a pair of blue jeans contains
about ten different pieces, from the pockets to the leg panels to the waistband
and belt loops.
M
A
N
A
U
A
L
C
U
T
T
I
N
g
Jeans Manufacturing
Jeans Manufacturing
Jeans Manufacturing
Receiving of
cut parts
Bulk
production
begins
In line
inspection
Production
continues
Ironing Rough
Checking
Button hole End line
Checking
Final
Checking
Measurement
checking
Tagging Packing
Quality audit
by buying
Sewing process flow:
The pieces of denim are ready to be sewn at this point. Sewing is
done in an assembly line fashion, with rows of industrial human-
operated sewing machines. Each sewer is assigned a specific
function, such as making only back pockets. First, the various
pockets and belt loops are assembled. Next, one sewer attaches
the pockets to the leg seams, another then sews the leg seams
together, and still another attaches the waist-band. Once the waist
band is secure, the belt loops may be stitched on and the buttons
attached. If the jeans include a zipper, it is then sewn into place,
and the pants are hemmed. Finally, the rivets are placed in the
appropriate places and the maker's label is sewn on last.
Sewing process:
Jeans Manufacturing
Jeans Manufacturing
Jeans Manufacturing
Jeans Manufacturing
Jeans Manufacturing
Jeans Manufacturing
Jeans Manufacturing
Washing process:
Some jeans are prewashed and/or stone-washed to alter the
appearance or texture of the finished jeans. Prewashing involves
washing the jeans in industrial detergent for a short time to soften the
denim. Stone-washing also means washing the jeans, but pumice is
added to the load, resulting in a faded appearance. Small stones (less
than one inch [one centimeter] in diameter) produce an even
abrasion, while large stones (about four inches [10 centimeters] in
diameter) highlight the seams and pockets and produce a more
uneven appearance.
Washing Machines
The completed pair of blue jeans is I 0 then pressed. They are
placed into a large pressing machine that steam irons the entire
garment at once in about a minute. A size tag is punched into the
material and the jeans are folded, stacked, and placed in boxes
according to style, color, and size before being sent to the
warehouse for storage. When the jeans are selected to be sent to a
store, they are put in large shipping cartons and sent on freight
trains or trucks.
Ironing process:
W
A
S
H
I
N
G
M
A
C
H
I
N
E
S
Jeans Manufacturing
Cotton is a desirable natural fiber for several reasons. Cloth made from cotton is wear resistant, strong,
flexible, and impermeable. Blue jeans are only as good as the cotton that goes into them, however, and
several tests exist for cotton fiber. All bales of cotton are inspected by the denim manufacturer for the
desired color, fiber length, and strength. Strength is the most important factor in blue jeans. It is
measured by using a weight to pull it. When the fiber breaks, the force used to break it is measured. The
cotton's strength index (weight of weight divided by weight of sample) is then calculated.
The finished denim cloth is carefully inspected for defects. Each defect is rated on a government-
defined scale ranging from one point for very small flaws to four points for major defects. Although
government regulations allow cloth with a high defect rating to be sold, in reality customers will not
accept denim with more than seven to ten defect points per square meter. Poor cloth is sold as damaged.
Denim is also tested for durability and its tendency to shrink. Samples of cloth are washed and dried
several times to see how they wear.
Blue jeans are also inspected after they are completed. If a problem can be corrected, the jeans are sent
back for re-sewing. The pair is then inspected again and passed. The buttons are inspected to ensure that
they and the buttonholes are of the proper size; the snaps, metal buttons, and rivets are checked for
durability and their ability to withstand rust. The zippers must be strong enough to with-stand the
greater pressures of heavy cloth, and their teeth durability must be checked as well. This is done by
subjecting a sample zipper to a lifetime of openings and closings.
Quality Control :
1 sur 26

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Jeans Manufacturing

  • 2. Raw Material True blue jeans are made out of 100 percent cotton, including the threads. Polyester blends are available, however, the over-whelming majority of jeans sold are 100 percent cotton. The most common dye used is synthetic indigo. The belt loops, waistband, back panel, pockets, and leggings of a pair of blue jeans are all made of indigo-dyed denim. Other features of blue jeans include the zipper, buttons, rivets, and label. Rivets have been traditionally made of copper, but the zippers, snaps and buttons are usually steel. Designers' labels are often tags made out of cloth, leather, or plastic, while others are embroidered on with cotton thread.
  • 5. Weaving theYarn: • The yarn is then woven on large mechanical looms. Denim is not 100 percent blue, as the blue dyed threads forming the warp (long, vertical threads) are combined with white threads forming the weft (shorter, horizontal threads). Because denim is woven with the blue threads packed closer together than the white threads and with the blue threads covering three out of four white threads, the blue threads dominate. (By examining a piece of denim closely one can detect the steep diagonal pattern that results from this process, which is known as a three-by-one right-hand twill weave.) Although mechanized looms make use of the same basic weaving procedure as a simple hand loom, they are much larger and faster. A modern "shuttle-less" loom (which uses a very small carrier instead of the traditional shuttle to weave the weft threads between the warp threads) may produce as much as 3,279 yards (3,000 meters) of cloth 3.28 or 4.37 yards (three or four meters) wide in a single week. As much as 1,093 yards (1,000 meters) of cloth may be rolled into a single huge bolt. • At this point the denim is ready for finishing, a term referring to a variety of treatments applied to cloth after it is woven. With denim, finishing is usually fairly simple.The cloth is brushed to remove loose threads and lint, and the denim is usually skewed in a way that will prevent it from twisting when it is made into clothing.The denim may then be sanforized, or preshrunk. Preshrunk denim should shrink no more than three percent after three washings.
  • 7. Cutting Of jeans: Once the desired design is selected, patterns from the design are cut from heavy paper or cardboard. Up to 80 different sizes are possible from one pattern. The pieces of denim are then cut with high speed cutting machines from stacks 100 layers thick. Excluding rivets, buttons, and zippers, a pair of blue jeans contains about ten different pieces, from the pockets to the leg panels to the waistband and belt loops.
  • 12. Receiving of cut parts Bulk production begins In line inspection Production continues Ironing Rough Checking Button hole End line Checking Final Checking Measurement checking Tagging Packing Quality audit by buying Sewing process flow:
  • 13. The pieces of denim are ready to be sewn at this point. Sewing is done in an assembly line fashion, with rows of industrial human- operated sewing machines. Each sewer is assigned a specific function, such as making only back pockets. First, the various pockets and belt loops are assembled. Next, one sewer attaches the pockets to the leg seams, another then sews the leg seams together, and still another attaches the waist-band. Once the waist band is secure, the belt loops may be stitched on and the buttons attached. If the jeans include a zipper, it is then sewn into place, and the pants are hemmed. Finally, the rivets are placed in the appropriate places and the maker's label is sewn on last. Sewing process:
  • 21. Washing process: Some jeans are prewashed and/or stone-washed to alter the appearance or texture of the finished jeans. Prewashing involves washing the jeans in industrial detergent for a short time to soften the denim. Stone-washing also means washing the jeans, but pumice is added to the load, resulting in a faded appearance. Small stones (less than one inch [one centimeter] in diameter) produce an even abrasion, while large stones (about four inches [10 centimeters] in diameter) highlight the seams and pockets and produce a more uneven appearance.
  • 23. The completed pair of blue jeans is I 0 then pressed. They are placed into a large pressing machine that steam irons the entire garment at once in about a minute. A size tag is punched into the material and the jeans are folded, stacked, and placed in boxes according to style, color, and size before being sent to the warehouse for storage. When the jeans are selected to be sent to a store, they are put in large shipping cartons and sent on freight trains or trucks. Ironing process:
  • 26. Cotton is a desirable natural fiber for several reasons. Cloth made from cotton is wear resistant, strong, flexible, and impermeable. Blue jeans are only as good as the cotton that goes into them, however, and several tests exist for cotton fiber. All bales of cotton are inspected by the denim manufacturer for the desired color, fiber length, and strength. Strength is the most important factor in blue jeans. It is measured by using a weight to pull it. When the fiber breaks, the force used to break it is measured. The cotton's strength index (weight of weight divided by weight of sample) is then calculated. The finished denim cloth is carefully inspected for defects. Each defect is rated on a government- defined scale ranging from one point for very small flaws to four points for major defects. Although government regulations allow cloth with a high defect rating to be sold, in reality customers will not accept denim with more than seven to ten defect points per square meter. Poor cloth is sold as damaged. Denim is also tested for durability and its tendency to shrink. Samples of cloth are washed and dried several times to see how they wear. Blue jeans are also inspected after they are completed. If a problem can be corrected, the jeans are sent back for re-sewing. The pair is then inspected again and passed. The buttons are inspected to ensure that they and the buttonholes are of the proper size; the snaps, metal buttons, and rivets are checked for durability and their ability to withstand rust. The zippers must be strong enough to with-stand the greater pressures of heavy cloth, and their teeth durability must be checked as well. This is done by subjecting a sample zipper to a lifetime of openings and closings. Quality Control :