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1. Basic Textiles term
Over lock Stitching 1
2.
3
3. Preparation for Stitching
5
4. Types of Overlock Stitches
16
11. Measurement Techniques
Stitching Defects 19
12.
Maintenance of sewing machines 28
13.
29
14. Safety measures
Yarn count Defines thickness of yarn. Higher the count, finer the yarn
Warp Lengthwise yarn in the fabric. Pass from weavers beam to cloth roller
Woven Woven fabrics are made by using two or more sets of yarn interlaced
Fabric at right angles to each other.
Fabric inspection
Cutting Fusing
Washing
Ironing
Finishing
Packing
Before starting actual machining, you should check that the needle of the machine is
of correct size, is sharp and correctly set. Thebobbin should be evenly set. Briefly,
the various steps of prepreparation are:
• Winding the bobbin
• Upper Threading
• Drawing the bobbin thread
• Tension adjustments
• Pressure and feed adjustments
•
It utilizes two independently driven feed dogs. The stroke of each feed dog can be
adjusted separately. If the stroke of the front feed dog is greater, then the fabric may
be gathering as it is sewn. If the rear feed dog has the greater stroke, then the fabric
may be stretched to provide a more extensible seam.
• A very wide seam width is created when the chain is serged with 2 or 3
thread stitch.
Flatlock stitching is the stitching that looks like overlocking on both sides of a seam
and is often used in swimwear, sportswear, on baby’s clothes, or just as a decorative
exposed seam. It creates a seam that is flat and has the same appearance both
inside and out.
Elements in Stitching
1. Needle
2. Looper
3. Spreader
Straight seams
Spiral seams
Decorative stitching on an
poket
Select the type of needle based on the textile construction (i.e knit vs woven), and
the needle size is determined by the thickness of the thread and the weight of the
fabric used for swing.
There are two needle sizing system :American and European. American Needle
sizes range from 8 to 19, and European sizes range from 60 to 120. Larger the
number, the larger the blade of the needle.
Denim/ Heavy 70/10 – These needles have a thick, strong shaft and
Jeans wovens 110/18 a very sharp point. They are used for
and stitching denim, canvas, duck and
denims other heavy, tightly woven fabrics. They are
also ideal for stitching through multiple fabric
layers without breaking.
Measurement Techniques
TAPE MEASURES: This plastic tape is 60" long with small metal tips on either end.
Most tape measures have imperial measurements on one side with the metric
equivalent on the other
1. High bust: measure around back and chest just above bust, keeping tape parallel
to the floor across back.
2. Bust: measure over the fullest part of bust.
3. Center front bodice length – measure center front from base of neck to waistline
tape..
4. Length from center back neck to tip of bust – measure from tip of bust around
neck to tip of other bust and divide the measurement into half.
5. Length from center back neck over bust to waistline – measure from waistline over
tip of bust around neck over other bust to waistline.
6. Center back bodice length – measure center back from base of neck to waist line
tape.
7. Back shoulder width – 4 inches below base of neck at center back, measure
distance from armhole to armhole, keeping tape parallel to floor and arms relaxed at
sides.
13. Waistline – measure waist circumference. Allow enough ease for comfort in
wearing finished garment.
14. High hip – measure high hip circumference 3 inches below waistline tape. Keep
parallel to floor
Stitching Defects
04 If needle thread loop size Needle size & thread size must be
is too small. adjusted.
Staggered stitch:
Variable stitch density: It must need to be the same amount of stitches per unit
length. If it is not, then it is called variable stitch density. The main cause of variable
stitch density is irregular feed of fabric due to insufficient pressure of pressure foot.
The following are the cause & remedies of variable stitch density formation given by
a table:
Frequent thread breakage: This breakage of thread again & again during sewing &
also, there needs more time & which is harmful for production. Specially, when there
needs to open out of sewing to solve the problem. The following are the causes &
remedies of frequent thread breakage formation given by a table:
Broken Stitches: When stitches are broken during sewing is called broken stitch.
Cause: Where the thread is being broken where one seam crosses another seam
(ex: bar tacks on top of waistband stitching, seat seam on top of riser seam.)
Problems of pucker:
Puckering is a wrinkle
appearance along a seam line in
a smooth fabric. It is one of the
frequently occurring defects.
Puckering shows that as if there
is too much fabric & not enough
thread in the seam & as if the
thread is drawing the seam in.
This is the reason why sewing
thread is often blamed for
causing puckering though there
are other factors as well as for
promotion of puckering. They are given below:
There is a great possibility of seeing seam pucker in case of more plied of fabrics
sewing together.
Causes:
If the shrinkage of sewn fabric plies are not same or equal than Seam pucker will
create after washing.
If the shrinkage percentage of area of two pieces fabrics is more than 2, then seam
pucker will occur after sewing the fabric together.
Remedies:
Use suitable feed mechanism.
Maintain shrinkage.
Take more care during sewing.
Causes:
If the tension on needle thread is higher than under thread then seam pucker will be
produced or relaxed.
Due to tension, the length of thread is extended a slight. When the fabric is displaced
or descend from the machine after sewing shrinkage of thread & fabric are occurred
due to tendency of coming to their original position.
If the shrinkage percentage of thread is higher than the fabric there is happened
seam pucker.
Remedies:
To give sufficient thread
tension.
To maintain shrinkage.
Unraveling Seams:
Re-stitched Seams:
Where there is a
"splice" on the stitch
line. The seam does
not appear to be 1st
quality merchandise, if
this occurs on
topstitching.
Causes:
Thread breaks or
thread run-out during sewing.
Cut or broken stitches during a subsequent treatment of the finished product (i.e.,
stone washing).
Remedies:
Use a better quality sewing thread. To minimize sewing interruptions, this may
include going to a higher performance thread specifically designed for that purpose.
Insure sewing machine adjustments and proper machine maintenance.
Make sure sewing machines are properly maintained and adjusted for the fabric and
sewing operation.
Observe sewing operators for correct material handling techniques.
A garment can be rejected due to damage of fabrics or yarn of fabrics in the seam
line. This is happened due to wrong needle selection or needle damage. The fabrics
are damage due to sew defected needle. But it may be happened in case of new or
fine needles. There are two types of fabric damaging are available given below:-
By using perfect size & shape of the needle & needle point without any defect.
By reducing the speed of sewing machine.
By using lubricant.
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By testing sew ability before sewing fabrics.
2) Needle heating damage: The damage of fabric due to friction occurred between
the needle & fabrics. The producing temperature in the needle is very high. The
fabric can be damaged with that temperature. There is a less possibility of damaging
in case of fabrics made from natural fibres. The following are the steps to be taken to
keep the fabrics free from this type of defect:
By reducing sewing speed so that there is less generating heat to the needle. But it
is harmful for large production.
By changing needle Size & shape so that there is less generating of heat to the
needle.
By sewing smaller length at higher speed.
By flown cool air on the needle during sewing so that the temperature can be
controlled.
By using lubricant to the needle.
By using Teflon coated needle.
Causes:
Due to variable shrinkage % of sewing thread & fabric, Seam pucker will create after
washing or ironing.
Cotton threads develop puckering when wet or after wash.
Causes:
When sewing is done by needle to densely woven fabrics or in which no. of warp &
weft yarns are more in one inch, there is happened seam pucker due to shrinkage of
fabric.
Remedies:
By using finer thread & needle.
By minimize stitch density.
By cutting & sewing on bias angle.
By using chain stitch instead of lock stitch.
To change fabric (if necessary).
Mismatched patterns:
Causes:
Seam pucker will create when two different size of patterns are sewn together.
The designer is responsible for this. But can be occurred due to wrong selection of
patterns.
Remedies:
Experienced pattern designer is needed.
Change or rectify the pattern.
If compressed air is used, make sure the air system is regulated properly and
has humidity dryers, filters and lubricator in the air lines.
Check for rusted areas due to excessive moisture in production area
Check Machines for wear on critical moving parts
Check for shake in needle bar due to worn needle bar bushings
Check for excessive movement in stitch forming devices, etc.
Check condition of critical screws
Check for missing screws
Check for defective screws that are difficult to tighten properly
Check condition of mechanics tools to see that they are being maintained
properly.
* With buttonhole or other specialized equipment, cleaning of the machine should not
be done with compressed air but with a soft bristle brush.
Safety Measure:
Always inspect the m/c before starting to work. Be sure it is clean and
threaded correctly, with no loose threads on the pulley belt and all guards in
place.Make only adjustments you have been trained to perform
When sewing on a power m/c, wear low shoes & close-fitting clothing. Avoid
loose fitting sleeves, sweaters, jewellery, ties, and ribbons when operating
the machine. If your hair is long, tie it back.
Always practice proper posture to reduce fatigue, help prevent accidents and
increase efficiency. If possible, adjust the chair height so that your feet rest
flat on the floor.