Amongst the following, the correct condition(s) that will reduce bumping during weaving is/are
The question asks to identify the correct condition(s) that help reduce bumping during the weaving process. Bumping in weaving can refer to various defects, often related to excessive stress, uneven impacts, or yarn breakages.
Weaving Bumping Reduction Condition
Among the given options, maintaining appropriate warp tension is crucial for smooth weaving operations and preventing defects like bumping.
Higher Warp Tension
Adequate or "higher" warp tension (compared to slack warp) ensures that warp yarns remain taut and stable throughout the weaving cycle. This prevents:
- Slack ends that can lead to crossed yarns.
- Uncontrolled vibration or movement of warp yarns.
- Uneven beat-up, where the reed impacts the cloth fell inconsistentially.
These issues can manifest as fabric defects or yarn breakages, contributing to 'bumping'. Therefore, correctly controlled, sufficient warp tension is essential for minimizing such problems.
Analysis of Other Options
- Reduction in sweep of the sley: While related to the reed's action, reducing sweep is not primarily aimed at preventing bumping caused by warp yarn issues.
- Higher pick density: This typically increases stress on warp yarns and requires greater beat-up force, potentially worsening bumping and warp breaks.
- Reduction of shed height: A reduced shed can increase friction and stress on warp yarns, possibly leading to more defects rather than reducing them.
Based on the typical causes of weaving defects related to bumping, maintaining proper warp tension is the most direct corrective measure among the choices provided.
Important Questions from FABR Loom Mechanisms Shedding
- Group I lists the components of the weaving machine and Group II lists their functions. Match the component with its function.
Group I Group II P Conjugate/matched cams 1 Driving the cloth roller with slip
driveQ Worm and worm wheel 2 Continuous positive take up
motionR Friction clutch device 3 Motion of sley in rapier loom S Lease rod 4 Separation of the warp sheet
forming the shed - Group I lists weaving machine related parameters and Group II contains the shortcomings of these parameters. Match the machine related parameter with its shortcoming.
Group I Group II P. Variable heald staggering 1. Not favourable for heavy fabric Q. High eccentricity ratio 2. Reduction in shed height R. Fixed heald staggering 3. Reduction of sley dwell S. Late shedding 4. Higher vibration in weaving machine Group I gives a list of loom motions and Group II contains loom systems. Match the motion from Group I with the corresponding system from Group II.
Group I Group II P. Shedding 1. Matched cam Q. Picking 2. Seven wheel R. Beat-up 3. Rapier S. Take-up 4.Jacquard Determine the correctness or otherwise of the following Assertion [a] and Reason [r]
Assertion: In shuttle loom, late shedding is preferred for filament weaving.
Reason: In late shedding, the timing of shed dwell matches with the timing of shuttle travel through the shed, and therefore, it minimises the rubbing of warp yarns.
For a shuttle loom, producing plain woven fabric, if each of the dwell periods of the shedding cam corresponds to one-third of crank shaft rotation, the sum of the two dwell periods of the cam (in degree) is_____.
