GATE (TF) Textile 2020 Question Paper Solution | GATE/2020/TF/35

A shuttle loom is a type of weaving machine used to produce fabrics by interlacing two sets of yarns at right angles to each other. The shuttle loom gets its name from the shuttle, a boat-shaped device that carries the weft yarn across the width of the fabric being woven.
In a shuttle loom, the warp yarns are stretched vertically on a frame or beam, and the weft yarns are passed through the warp yarns by the shuttle. The shuttle is propelled back and forth across the width of the fabric by a mechanism called the picking mechanism, which is usually powered by a cam or a dobby.
Shuttle looms were widely used in the textile industry for centuries, from the early Industrial Revolution until the mid-20th century, when they were gradually replaced by more advanced weaving machines, such as air-jet looms and rapier looms. Shuttle looms are still used in some niche applications, such as the production of denim fabrics, where the characteristic weft-faced twill weave pattern is achieved by the use of shuttle looms.
Shuttle looms have some advantages, such as their ability to handle a wide range of yarn types and their low operating cost, but they also have some limitations, such as their slow speed and the risk of defects caused by the shuttle itself. Overall, shuttle looms played an important role in the development of the textile industry and the production of a wide range of fabrics.

In a shuttle loom, the sley (also spelled “slay”) is a part of the weaving mechanism that helps to beat the weft yarn into place after each pass of the shuttle.
The sley consists of a frame that holds a series of thin, flat metal or wooden rods called “reed wires.” These wires are evenly spaced and have small notches or dents in them, which help to hold the warp threads in place while the weft thread is woven through them.
During the weaving process, the sley is moved back and forth by the loom’s mechanism, pushing the weft thread firmly against the previous row of woven threads. This creates a tightly woven fabric. The spacing of the reed wires can be adjusted to create different fabric densities and patterns.

The sley velocity in a shuttle loom refers to the speed at which the sley moves back and forth during the weaving process. This speed is determined by the loom’s mechanical settings and can be adjusted to control the tension and density of the fabric being woven.
In general, the sley velocity needs to be carefully controlled to ensure that the weft thread is inserted and beaten into place with just the right amount of force. If the sley moves too slowly, the fabric may be too loose or have gaps between the threads. If it moves too quickly, the threads may be damaged or the fabric may be too tightly woven.
Sley velocity is typically measured in terms of picks per minute (PPM), which refers to the number of times the sley moves back and forth in one minute. The specific sley velocity required for a particular weaving project will depend on a variety of factors, including the type of fabric being woven, the yarns being used, and the desired pattern and density of the final product.

Sley acceleration in a shuttle loom refers to the rate at which the sley’s speed changes during the weaving process. This acceleration can be adjusted by the loom’s mechanical settings to control the weaving tension and prevent fabric defects.
During the weaving process, the sley is moved back and forth by the loom’s mechanism with a specific velocity. However, when the sley reaches the end of its travel and changes direction, it undergoes a brief acceleration period as it begins to move in the opposite direction. This acceleration can affect the tension on the warp and weft threads and potentially cause defects in the woven fabric.
To control this acceleration and maintain consistent weaving tension, shuttle looms are designed with mechanisms to regulate the sley’s speed and direction changes. For example, some looms use a device called a “crank motion” to smoothly reverse the sley’s direction and reduce the acceleration at the end of each stroke.
By adjusting the sley acceleration, weavers can ensure that the fabric is woven evenly and with the correct amount of tension. This is important for creating high-quality woven products that are strong, durable, and visually appealing.

In a shuttle loom, the “front center” refers to the position of the reed (which is part of the sley) relative to the loom’s other components. The front center is located at the front of the loom, near the operator.
The front center is an important reference point for the weaver because it determines the position of the warp threads as they are woven into the fabric. The reed is positioned at the front center and held in place by a metal or wooden frame called the “beater.” As the shuttle moves back and forth across the loom, the reed is used to push the weft threads tightly against the previous rows of woven threads.
The position of the front center can be adjusted to accommodate different fabric widths and to create different patterns in the woven fabric. This is done by adjusting the position of the warp beam, which holds the warp threads under tension, and the cloth beam, which collects the woven fabric as it is produced.
In summary, the front center in a shuttle loom is a key reference point for the weaver, as it determines the position of the warp threads and allows for adjustments to be made to produce a wide range of fabrics.

In a shuttle loom, the back center refers to the part of the loom where the shuttle is picked up and delivered during the weaving process. The shuttle is a small boat-shaped device that carries the weft yarn (horizontal yarn) across the loom from one side to the other.
The back center is located at the back of the loom, where the shuttle is loaded with the weft yarn. It is usually a raised platform or a shuttle raceway that holds the shuttle and guides it as it moves across the loom.
The back center plays a crucial role in the operation of a shuttle loom, as it must be precisely aligned with the other components of the loom to ensure the proper movement of the shuttle and the even insertion of the weft yarn into the warp (vertical yarn) threads. The back center must be carefully maintained and adjusted to ensure smooth and efficient operation of the loom.