Ring doubling and two for one twister, quality required by yarn to get best doubled yarn. Formula for double yarn count.
Objectives of doubling
- To increase strength of yarn
- To increase smoothness, evenness, lusture, uniformity and compactness of yarn.
- To obtain better deposition of twist.
- Jeans sewing thread
- type cord
- cable yarn
- tufting yarn
Types of Doubling
- 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
- 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.
Qualities of Single yarn to get best Doubled yarn
- 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.
Formula for Double Yarn Count
- Single yarn of same count
- 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%)
|Final count =||Single yarn count|
|No. of doubling|