Knitting shrinkage is a dimensional change that results in a decrease in length or width of a knitted fabric when subjected to conditions like washing, drying, or chemical treatment. There are several types of shrinkage, including relaxation shrinkage during manufacturing, residual shrinkage after washing, felting shrinkage in wool fibers due to moisture and mechanical action, and compressive shrinkage through controlled compression. Factors influencing shrinkage include yarn twist, stitch length, fabric weight, yarn elasticity, fabric construction, tension during garment sewing, and fiber and yarn stability. Proper prevention of knitting shrinkage requires correct knitted construction, elimination of excessive tensions, untwisting yarns below 65% moisture,

1. FACTORS AFFECTING IN
KNITTING
SHRINKAGE
DR:SHERINE ELKATEB
PRESENTED BY:MOHAMED ELMIDANY
NADA EL-ABD

2. DEFINITION
• A dimensional change resulting in a decrease in the
length or width of a specimen subjected to specified
conditions is known shrinkage
• Reduction in length and width of fabric induced by
conditioning, wetting, steaming, chemical treatment, wet
processing as in laundering

3. SHRINKAGE TYPES
• Relaxation shrinkage :
During manufactures fabrics and their component yarns are subjeceted to tension
under varying conditions of temperature and moisture content, after manufacturing
when the fabric is taken from the machine and keep on floor or store room, then the
fabric tends to shrink, this type shrinkage is called relaxation shrinkage.
• Residual shrinkage:
after washing the fabric is shrunk. This type of shrinkage is called
residual shrinkage. Residual shrinkage is the main factor of garments
industry

4. • Felting shrinkage:
In case of wool fibers dimensional changes can be
magnified by felting shrinkage. When untreated wool
fibers are subjected to mechanical action in the
presence of moisture
•Compressive shrinkage:
A process in which fabric is caused to shrink in length
by compression. The process often referred to as
controlled compressive shrinkage.

5. CAUSES-INFLUENCING FACTORS
• Causes :
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.
•Influencing factors:
1)Twist factor: twist factor increases so that shrinkage will be
increases.
2)Stitch length: stitch length increases so that shrinkage will be
increases
3) GSM: GSM increases so that shrinkage will be decreases.
4)Elasticity of yarn.

6. FACTORS
•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
•Stability of Fiber and Yarns: Improper stabilization could lead to excessive
shrinkage especially in blends where synthetic fiber shrinks differentially than
the cellulosic fibers.

7. HOW TO PREVENT IT?
• 1.correct knitted construction is essential
• 2.excessive tensions should be eliminated during processing
(from grey inspection to finishing)
• 3.untwisting and extraction to below 65% moisture content
• 4.padding the correct softener on to the fabric
• 5.spreading with overfeed and pre-drying to approximately
30% moisture
content
• 6.step by step shrinkage reduction.

8. THANK YOU