Difficulty: Easy & Basic
Which traveler profile suits synthetic-fibre ring spinning?
A Half-round profile
B Triangular blade
C Flat square profile
D Open coil profile
Answer: A. Half-round profile. A half-round traveler profile seats well on the ring for synthetic and blended fibres.
In a roving frame, the tension-change wheel adjusts which drafting setting?
A Cop taper
B Roving count
C Flyer speed
D Apron tension
Answer: D. Apron tension. The roving-frame tension-change wheel adjusts apron tension in the drafting system.
Why are very soft top-roller coverings unsuitable?
A Poor recovery and wear
B They remove noil
C They reduce twist direction
D They increase fibre length
Answer: A. Poor recovery and wear. Very soft coverings may not recover from repeated squeezing and can wear quickly.
In V drafting, which roller is shifted rearward?
A Spindle rail
B Front bottom roller
C Ring traveler
D Back top roller
Answer: D. Back top roller. The back top roller is shifted rearward in the V drafting arrangement.
What added guidance does V drafting create?
A More rotor back doubling
B Larger fibre-encircling curve
C A longer ring rail
D A wider cop shoulder
Answer: B. Larger fibre-encircling curve. The larger encircling curve provides additional fibre guidance.
Builder motion winds roving into what package form?
A Flat woven sheet
B Rotor-groove package
C Cross-wound cone only
D Parallel layers, conical ends
Answer: D. Parallel layers, conical ends. Roving builder motion forms a parallel-wound package with conical ends.
Why is bobbin-rail lift shortened layer by layer?
A Make a rotor groove
B Create tapered ends
C Increase yarn twist
D Reduce fibre maturity
Answer: B. Create tapered ends. Shortening the lift produces the taper at the package ends.
At the end of a roving-package layer, what does the bobbin rail do?
A Stops permanently
B Changes fibre type
C Reverses direction
D Removes the flyer
Answer: C. Reverses direction. The rail reverses to place the next layer in the opposite direction.
During roving-frame operation, which speed does the cone drive change?
A Bottom cone drum
B Comber top comb
C Rotor navel
D Traveler ring
Answer: A. Bottom cone drum. The position of the belt between cone drums changes bottom-cone speed.
Which mechanism combines fixed and variable drives?
A Winding clearer
B Opening roller
C Differential gear
D Spindle brake
Answer: C. Differential gear. A differential drive combines fixed and variable motion for package building.
As roving-bobbin diameter grows, what happens to bobbin rpm?
A It doubles
B It decreases
C It stays fixed
D It becomes zero
Answer: B. It decreases. Rotational speed is reduced as package diameter grows to maintain winding conditions.
Which component moves the roving-frame bobbin rail?
A Rotor navel
B Bottom cone drum
C Comber top comb
D Ring traveler
Answer: B. Bottom cone drum. The bobbin rail receives motion from the bottom cone drum.
Compared with ring yarn, rotor yarn often has what hairiness?
A No fibre ends
B Higher hairiness always
C Identical hairiness
D Lower hairiness
Answer: D. Lower hairiness. NPTEL describes rotor yarn as having lower hairiness than ring-spun yarn.
Rotor yarn can have which abrasion-related advantage?
A No fibre migration
B Lower package size
C Higher abrasion resistance
D More twist direction
Answer: C. Higher abrasion resistance. Rotor yarn is reported to have greater abrasion resistance than ring yarn.
Which rotor limitation affects very fine yarn counts?
A Limited fine-count range
B No package formation
C Too much ring friction
D Excessive filament length
Answer: A. Limited fine-count range. Rotor spinning has limitations at very fine counts.
What feature supports high rotor-spinning production rates?
A Manual combing
B Slow cop building
C Separate roving winding
D Continuous open-end formation
Answer: D. Continuous open-end formation. Open-end formation enables high production compared with conventional ring spinning.
In air-jet yarn, which fibres bind the core?
A Comber noil
B Wrapper fibres
C Rotor waste
D Card flats
Answer: B. Wrapper fibres. Wrapper fibres bind the core in air-jet yarn structure.
Air-jet yarn core fibres are generally arranged how?
A Tightly ring-twisted
B Coiled into a cop
C Randomly woven
D Mostly parallel
Answer: D. Mostly parallel. The core fibres are largely parallel, while wrapper fibres bind them.
Open-end systems can raise output by separating which operations?
A Twisting and winding
B Dyeing and finishing
C Warping and sizing
D Carding and drawing
Answer: A. Twisting and winding. Open-end methods separate twist insertion from winding, enabling higher production than ring spinning.
In electrostatic spinning, what attracts fibres toward the twisting element?
A Matching colour
B Higher tex
C Opposite electric charge
D Ring friction
Answer: C. Opposite electric charge. An oppositely charged element attracts the charged fibres.
Which yarn type generally has the strongest fibre orientation and parallelisation?
A Ring-spun yarn
B Friction-spun yarn
C Vortex-spun yarn
D Rotor-spun yarn
Answer: A. Ring-spun yarn. Ring-spun yarn generally shows the best fibre orientation and parallelisation among these systems.
Why is a round cop bottom used?
A Higher fibre maturity
B Larger spinning triangle
C More rotor doubling
D Smooth unwinding
Answer: D. Smooth unwinding. A rounded cop bottom helps coils unwind smoothly and reduces slough-off.
Rotor twist per unit length depends on what ratio?
A Ring/traveler ratio
B Rotor/withdrawal ratio
C Cop/rail ratio
D Navel/spacer ratio
Answer: B. Rotor/withdrawal ratio. Rotor twist per unit length depends on rotor rotational speed relative to yarn withdrawal speed.
What force holds fibres against the rotating rotor groove?
A Ring-traveler drag
B Air-jet pressure
C Centrifugal force
D Comber friction
Answer: C. Centrifugal force. The rotating rotor presses transported fibres into its groove by centrifugal action.
Why maintain sufficient top-roller pressure in drafting?
A Form a rotor groove
B Remove all neps
C Control fibre movement
D Increase yarn colour
Answer: C. Control fibre movement. Adequate pressure helps the roller nip control fibre movement during drafting.