GATE (TF) Textile 2010 Question Paper Solution | GATE/2010/TF/33

Drafting waves are formed during the process of spinning fibers into yarn. The drafting process involves pulling fibers apart and aligning them before twisting them together to create a single strand of yarn. Here’s how drafting waves are formed:

Preparation: The fibers are first prepared by either carding or combing. This separates and aligns the fibers to create a uniform sliver or roving.

Attaching to the spindle: The end of the roving is attached to a spindle or bobbin on a spinning wheel or spinning frame.

Drafting: The roving is then fed through a drafting zone, where rollers pull the fibers apart and align them in a parallel arrangement. The distance between the rollers determines the amount of fiber that is drafted or pulled apart.

Tension: The drafting process creates tension in the fibers, which causes the fibers to become thinner and longer. The fibers also become more uniformly aligned, which creates a smoother yarn.

Twisting: Once the fibers have been drafted to the desired thickness, they are twisted together by the spindle or bobbin to create a single strand of yarn. The twisting action also helps to lock the fibers in place.

Formation of drafting waves: During the drafting process, the fibers can become stretched and compressed, creating waves in the roving. These waves are known as drafting waves and are a natural byproduct of the drafting process.

Overall, the drafting process is crucial for creating high-quality yarn, and the formation of drafting waves is a normal part of this process.

A periodic fault is a type of fault that occurs at regular intervals, often in a cyclic pattern. This type of fault is commonly associated with electrical systems, such as power grids or electronic circuits, but can also occur in mechanical systems or other types of systems that operate cyclically.

Periodic faults can be caused by a variety of factors, including:

Oscillations or resonances: When a system oscillates or resonates at a specific frequency, it can cause periodic faults to occur at regular intervals.
Mechanical wear: In mechanical systems, periodic faults can be caused by wear and tear on moving parts, which can cause vibrations or other cyclical movements.
Environmental factors: Changes in temperature, humidity, or other environmental factors can also cause periodic faults to occur.
Electrical or electronic component failure: Faulty electrical or electronic components can also cause periodic faults to occur in a system, especially if the component is part of a system that operates cyclically.

Periodic faults can be difficult to diagnose and repair, as they often require specialized equipment or expertise to identify the underlying cause. However, they can cause serious problems if left untreated, such as power outages or equipment damage, so it is important to address them as quickly as possible.

Yarn hairiness refers to the amount of fiber ends that protrude from the surface of a yarn. These fiber ends, also known as protruding fibers or flyings, can make the yarn appear fuzzy or hairy and can affect the quality of the finished product.
Yarn hairiness can be caused by a variety of factors, including:

Fiber length: Shorter fibers tend to create more hairy yarns than longer fibers. This is because shorter fibers have a higher likelihood of becoming dislodged from the yarn surface during processing.

Fiber type: Different fiber types have different levels of hairiness. For example, cotton and wool fibers tend to create more hairy yarns than synthetic fibers like polyester or nylon.

Spinning method: The spinning method used to create the yarn can also affect its hairiness. Yarns that are spun at a high speed or with a high twist tend to have less hairiness than those spun at a lower speed or with a lower twist.

Processing techniques: The processing techniques used to prepare the fibers for spinning can also affect yarn hairiness. For example, carding or combing the fibers can help to remove any loose or protruding fibers before spinning.

Yarn hairiness can be measured using specialized equipment, such as a hairiness tester. Manufacturers often strive to minimize yarn hairiness in order to create high-quality, smooth yarns that are suitable for a variety of applications, from clothing to home textiles to industrial materials.

In rotor spinning, wrapper fibers are formed as a result of the interaction between the yarn being spun and the rotating rotor.
As the rotor spins, it creates a strong airflow that pulls the fibers towards it. The fibers then wrap around the rotor and are twisted together to form the yarn. However, some fibers are not immediately caught by the rotor and are instead carried along by the airflow. These fibers tend to accumulate on the surface of the yarn, forming a layer known as the wrapper fibers.
The wrapper fibers are important because they help to protect the inner core of the yarn from abrasion and damage during subsequent processing. Additionally, the presence of wrapper fibers can also improve the appearance and handle of the finished yarn.
The amount and distribution of wrapper fibers can be controlled by adjusting various spinning parameters such as rotor speed, air pressure, and yarn tension.