This document discusses quality control in fabric manufacturing. It outlines several factors that affect quality at different stages of production, including winding, warping, sizing, knitting, and weaving. Specifically, it notes that winding tension, knot strength, and machine functioning impact quality. In warping, beam and drum conditions, stop motions, and length measurements are important. For sizing, factors like viscosity, pressure, tension, and speed influence size pickup. Drying is impacted by speed, density, pickup, and temperature. Common fabric defects from knitting and weaving like loops, bars, holes, and stains are also described. Maintaining quality at all stages of production is essential to avoiding defects and customer rejections.

1. Quality Control
in
Fabric Manufacturing
Md. Mashud Raihan, Lecturer, DIU

2. POINTS TO BE MAINTAINED FOR QUALITY
WINDING
 Appropriate winding tension
 Free from different count mixing
 Winding machine should be free from mechanical fault (For example, Free from
defective traversing motion, fault free yarn guide etc.)
 The knots & splices must have sufficient strength and stability.
 Winding should be carried out at high speed in order to get high productivity. At
high speed less time & auto coner will be required.

3. FACTORS AFFECTING THE QUALITY OF
WARPING
 Condition of the beam flange: If the beam flange get damaged then unwinding
at the two edges will not be satisfactory. There will also be problem in sizing and
weaving. Beam flange get damaged due to improper handling and improper
storage. Empty bobbin should be checked on a regular basis and repairment
should be done on a regular basis.
 Stop motion: Stop motion should be capable of stopping the machine
immediately after any end break. Sometimes flying dust and tufts gets stuck in
the stop motion so that the machine does not stop even after any end break.
Creel fans should work properly.
 Beam barrel diameter: Smaller dia gives high unwinding tension during sizing,
though it can accommodate more yarns.

4. FACTORS AFFECTING THE QUALITY OF
WARPING
 Condition of the driving drum: Driving drum is used to drive the warp beam by
means of frictional force. In case of modern machines the warp beam is driven
directly, however a drum is used to stop the rotating beam instantly. Any
roughness of the drum is therefore dangerous for the safety of the yarn.
 Length measuring motion: This device should work properly. Miss
representation of the actual length may cause unnecessary wastage or shortage
of yarn. The size% calculated from the length of the yarn. So a wrong length
measuring will lead to incorrect estimation of the size%.
 Density of the beam: In order to obtain satisfactory result the warp beam must
be sufficiently compacted. The compactness should not be achieved by means
of yarn tension rather it has to be achieved by means of creating pressure by
drum

5. FACTORS INFLUENCING SIZE PICK UP %
 Viscosity of the size paste in the size box
 Squeezing pressure & condition of squeezing nip.
 Yarn tension
 Yarn twist
 Speed of the sizing machine
 Duration of immersion in the size paste
 Level of size paste
 Density of the warp
 Dia of the yarns

6. FACTORS INFLUENCING DRYING
EFFICIENCY
 Speed of sizing
 No of end in warp sheet (density)
 Pick up % of size to be applied
 Linear density of warp
 Box concentration
 Temperature of the drying cylinder
 Area of contact around the cylinder

7. CONSEQUENCES OF FABRIC DEFECTS
 The customer (garments manufacturer) may totally reject the defective fabric.
 If the rate of defect is not very high in that case fabric is accepted with certain
penalization in terms of either reduction of cost of the fabric or additional fabric
is demanded by the buyer. This means that fabric defect may ultimately
reduce the profitability of the concern entrepreneur.
 The garment manufacturer will be in trouble in handling a defective fabric in
the cutting table.
 In spite of all preventive measures, garments are produced with fabric defects
that result in ultimate rejection of the particular garment or even rejection of
the whole lot.

8. KNITTING FAULTS
 Loop length variation: This problem arises in weft knitting due to-
1. Fluctuation in yarn variables
2. Fluctuation in machine variables
1. Fluctuation in yarn variables: Yarn variables are-
a) Yarn count b) Twist c) Package hardness d) Flexibility e) etc.
2. Fluctuation in machine variables: Machine variables include-
a) Temp. b) Machine gauge b) Cam setting d) Yarn tension e) Fabric take-
down tension f) Needle & sinker timing.

9. KNITTING FAULTS
 Barre: This defect occurs in circular knitting machines due to-
1. Lot mixing of yarn
2. Variation in package hardness
3. Improper yarn tension
4. Uneven dyed yarn
 Holes: Holes are caused by-
1. Broken needle
2. Less strength of yarn, which breaks during loop formation
3. Presence of mineral particle in fibre/yarn ( In this case, hole is created
during bleaching)

10. KNITTING FAULTS
 Lycra out: This fault is occurred if the machine is not immediately after the
breakage of lycra during production. It is happened due to-
1. Careless supervision
2. Faulty auto stop motion
 Needle mark: Needle marks is caused by the defective needles and faulty
needle setting.
 Oil staining: Oil staining is occurred due to dirty machine or improper
lubrication.
 Fly yarn: This fault is occurred when the flying yarn get mixed with the yarn
during knitting.

11. KNITTING FAULTS
 Crease mark: Crease mark is caused by-
1. Yarn tension variation
2. Lower GSM of fabric
3. Faulty fabric take-up
 Drop stitch: Main causes of drop stitch are-
 Defective needles
 Wrong setting of yarn feeder.
 Bad take up.
 Sinker mark: Sinker mark is caused by the defective sinker.
 Etc.

12. FABRIC QUALITY AFFECTED DURING WEAVING
 Fabric width
 Fabric length
 EPI in the fabric
 PPI in the fabric
 GSM
 Design of fabric
 Softness of fabric
 Air permeability of fabric
 Water permeability of fabric
 Strength of fabric
 Appearance of fabric
Of them fabric length and width may be decreased due to shrinkage.
EPI and PPI may also be increased due to shrinkage of fabric.

13. DEFECTS OF WOVEN FABRICS
Missing ends: The most common missing end is
characterized by a gap of one or more warp ends in the fabric.
Reed marks: Due to this fault, cloth shows irregular spacing
between groups of warp yarns across the fabric width. It may
be caused by damaged or defective reed.
Shuttle marks: Width wise marks due to abrasion of warp
yarns by the shuttle.
Stains: Stains are major problem on woven fabric. Oil grease,
dust, soil, carbon particles in the air, sweat etc. are the causes
of stain. Most of the stains are caused by poor material
handling and carelessness of workers. Certain stains can be
removed by solvents.

14. DEFECTS OF WOVEN FABRICS
 Bar: It is a band running across the full width of cloth due to difference in
appearance from its adjacent surface. This term covers a number of specific
defect as below:
1. Pick bar: A bar due to difference in pick spacing. The causes of pick bars are faulty
gearing in take-up motion.
2. Starting mark: An isolated narrow marks along the pick. It is occurred due to restart
of weaving after- a) Unweaving or Pulling back b) Prolonged loom stoppage.
3. Tension bar/Shiner: A bar due to difference in weft tension.
4. Weft bar: A bar due to difference in count, twist, luster, color or shade of adjacent
groups of weft yarns

15. DEFECTS OF WOVEN FABRICS
 Box mark: Box mark is a widthwise fine line showing stained or injured weft
due to the rubbing of shuttle when it rebounds. The causes of box mark are-
1. Dirty box
2. Dirty shuttle
3. Weft flying too freely
4. Etc.
 Broken pattern: This defect may be due to wrong drawing of threads,
insertion of pick in wrong shed, incorrect lifting of warp threads.
 Broken pick: A pick missing from a portion of the width of the fabric due to
rough shuttle eyes, poor winding, weft yarn breakage, improper pirn insertion
etc.

16. DEFECTS OF WOVEN FABRICS
 Cut weft: It is occurred due to weak weft. It is like a pin hole.
 Defective selvedge: There may be various types of defective selvedges as
stated below:
1. Curled selvedge: It is occurred due to incorrect balance of cloth structure between
body and the selvedge.
2. Cut selvedge: This is the selvedge with cuts or tears due to selvedge sticking to
emery cloth.
3. Uneven selvedge: It is occurred due to variation in weft tension.
4. Etc.
 Fuzzy: This is the fibrous appearance of the cloth due to presence of hairy or
abraded yarn