1. Why doubled yarns are preferred?
Ans: The object of doubling is to double the individual threads. Doubling
avoidsunevenness and the strength of doubled yarn is correspondingly better
than thesingle thread. So doubled yarns are prefer
Assignment : 1
1. The count of the carded sliver is 0.12s Ne.
PROCESS-A (Lap doubling): 24 carded slivers are combined and a draft of 2.2 is applied
to get the sliver lap. 6 such laps are combined in the ribbon lap machine and draft of 6.8
is applied to o
Assignment : 2
1. A roving machine with all the drafting rollers of same diameter has the following
Feed sliver count
Roving Twist Multiplier
Back drafting roller speed
Ring Spinning Machine
1. What are the objectives of ring spinning?
Ans: There are three objectives for ring spinning:
To draw the roving to the desired degree of fineness.
To impart sufficient twist to the emerging strand of fibres to from continuo
Assignment 5 : New Spinning systems
1. A 48 head friction spinning machine, running at 98% efficiency, is producing 60 tex cotton
yarn of 600 twist/m. The friction drum speed and diameter are 4000 rpm and 50 mm
respectively. Calculate the productivity of
1. What is the need for roving frame in the ring spinning system?
Ans: In ring spinning system, conversion of sliver into yarn through a single
step has not succeeded since the total draft needed is in the range 300-500
which is very difficult
1. What is combing?
Ans: Comber is a process by which quantity of short fibers and remnant
fragments of impurities present in a carded or drawn sliver are minimized to
give a clean sliver, having more of a rectangular staple diagram, with the
Assignment 6:Yarn Doubling
1. A Two-For-One twister is running at 9,000 rpm with 96% efficiency, and producing 4-ply yarn
from 60 denier polyester multi-filament yarn, 90 Ne dyed cotton single yarn, 15 tex grey combed
cotton single yarn and 50 Nm 100% woo
Assignment : 3
In a ring frame, the traveler travels at the speed of 120 ft/sec on a 1.75 inch
diameter ring when the wind-on diameter on the bobbin is 1.25 inch. The 20 tex
100% cotton yarn is being spun from 1.0 Ne roving. What is the spindle speed
New Spinning systems
1. What are all the merits of rotor yarn over ring spun yarn?
a. Fibres are compactly oriented.
b. More abrasive strength
c. Production speed is 200 m/min whereas ring spinning production
speed is 20 m/min
d. More uniformity
Ring Spun Yarns
1. How fibre length affects ring spinning?
Ans: A longer fibre can be spun to a finer counts and gives a better
spinning performance. In general, the longer the fibre, the higher the yarn
tenacity. Too long a fibre gives processing pr
1. A spinning mill has 60,000 ring spindles and it produces only 40 s Ne cotton yarn.
The yarn TPI is 26.4, the spindle speed is 18,000 rpm and the ring frame
utilization percent is 91.0%. The waste produced as a percentage of t