Textile testing & Quality Control-II

2. SUBMITTED BY:
ID’s NO : 121-23-2869
121-23-2888
121-23-2934
113-23-2641
DEPERTMENT : TEXTILE ENGINEERING
TOPIC : SHRINKAGE

3. Introduction. . .
Shrinkage is the process in..
which a fabric becomes smaller than its original size,
usually through the process of laundry.
Shrinkage is one of main disadvantages of fabrics .
Or
A dimensional change resulting in a decrease in the length
or width of a specimen subjected to specified conditions is
known shrinkage.

4. Shrinkage testing procedure ……
1)Relaxation shrinkage.
2)Felting shrinkage.
3)Compressive shrinkage .
4)Residual shrinkage.

5. Influencing factors
…….
Shrinkage is mainly due to yarn swelling and the resulting crimp
increase during washing in case of cotton fabrics. Yarn swelling
percentage is more in polyester cotton blending yarn……..
Twist factor: twist factor increases so that shrinkage will be
increases.
Stitch length: stitch length increases so that shrinkage will be
increases.
GSM : GSM increases so that shrinkage will be decreases.
Elasticity of yarn.

6. The factors that control
shrinkage in fabrics or garments
are :………
Stability of Fiber and Yarns: Improper stabilization
could lead to excessive shrinkage especially in
blends where synthetic fiber shrinks differentially
than the cellulosic fibers.
Construction: A tighter fabric construction reduces
potential shrinkage
Yarn twist: Optimum twist (based on yarn size) is
very important for controlling shrinkage and torque.
Type of Weave or Knit: Pain weave of Jersey knit
show more resistance to shrinkage than other types.
Tension During Sewing of Garments: Uneven or
too much sewing tension can lead to differential
shrinkage causing puckering in the seam areas.

7. Shrinkage Control ………
Correct knitted construction is essential.
Excessive tensions should be eliminated during
processing (from grey inspection to finishing)
Untwisting and extraction to below 65% moisture content.
Padding the correct softener on to the fabric
Spreading with overfeed and pre-drying to approximately
30% moisture content.
Step by step shrinkage reduction.

8. 1) Shrinkage Template & Scale also measures the dimensional
changes in fabrics after laundering, dry cleaning etc.
2) Template and shrinkage scale made up of transparent polymer
plate to apply standard pressure on test specimen.

9. Features of Shrinkage Template & Scale
………………..
To determine directly the % dimensional
change (shrinkage) in all types of fabrics.
Fine calibrated Shrinkage Template with 18" x
18" & 10" x 10" benchmarks length-wise
& width-wise.
Two fine tipped black & yellow fabric markers
are supplied for accurate marking on light &
dark color fabrics.
Calibrated scale to evaluate shrinkage &
stretch directly Up to 15%.

10. Remedies ……
As already noted, shrinkage is a serious problem with
knitted fabrics. Even a target shrinkage of 5% maximum in
both length and width directions is difficult to achieve. Slit
(open-width) fabrics are stentered with overfeed and
without undue stretching, then often Sanforised to reduce
potential shrinkage.
Both open-width and tubular fabrics are dried on what is
effectively a continuous open-width ‘tumbler’ dryer in
which the fabric passes through the machine in a relaxed
state on a continuous belt and air is blown from jets
through the fabric. Both types of fabric can then be
subjected to compacting in which the fabric is overfed and
steamed.
It is claimed that tubular, mercerized and compacted
knitted fabric can have a shrinkage as low as 1%.

11. Shrinkage graph. . . . . . .