Types of Doubling

• To increase strength of yarn
• To increase smoothness, evenness, lusture, uniformity and compactness of yarn.
• To obtain better deposition of twist.

Doubling Uses

• Jeans sewing thread
• type cord
• cable yarn
• tufting yarn

1. Ring Doubling

   The difference of ring doubling from ring is:

   • No drafting
   • Creel in system is different & creel contains yarn(No rove)
   • Roller combination is different

   Doubling yarn is designated as follows:

   	Ends up of	40	Count 2/40
   	Ends up of	10	Count 3/10

 

2. Two For One twister (TFO)

   Here yarn is transferred to cone, then two ends yarns are combined (Doubled) and wound on a cone without twisting. Then the yarn is supplied to twister m/c where twist is applied in such a way that one revolution of rotating disc inserts two round of twist. The twisted yarn is then wound on a cone.

• The elongation of the yarn under lea strength tension should be uniform of the same count.
• The twist should be uniform throughout
• The breaking strength of yarn should not vary too much
• 4% tolerance on either side should be allowed.

• Single yarn of same count

Final count =	Single yarn count
	No. of doubling



• Resultant count of component thread
  • Count: 1/N = 1/N1+1/N2 (N = Resultant counts, N1, N2= of same count yarn)
  • TPI of doubled yarn = TPI of single yarn (60-70%)