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Semester 2: B.Sc. Textile and Fashion Designing
Preparatory Process - Classification of fabric forming methods, Winding types and defects
Preparatory Process
The preparatory process in textile manufacturing involves various steps that prepare fibers for fabric formation. This may include steps such as fiber selection, opening, carding, and drawing. Each step is crucial for ensuring that the fibers are processed efficiently and are ready for the subsequent fabric formation methods.
Classification of Fabric Forming Methods
Fabric forming methods can be classified into various categories such as weaving, knitting, and non-woven techniques. Weaving involves interlacing two sets of yarns, knitting involves interlooping yarns, and non-woven processes involve bonding fibers directly without the use of yarn.
Winding Types
Winding is a process involved in preparing yarn for further processing. Different types of winding methods include cheese winding, cone winding, and pirn winding. Each type caters to specific yarn characteristics and requirements for further textile production.
Defects in Fabric Formation
Defects in fabric formation can arise due to various factors such as improper preparation, faulty machinery, or poor-quality materials. Common defects include yarn breakage, uneven tension, and weave imperfections, which can affect the quality and usability of the final fabric.
Sizing Process - Types of warping, Sizing ingredients and defects
Sizing Process
Types of Warping
Warping refers to the process of preparing the yarns for weaving. Several types of warping include: 1. Beam Warping: Involves winding warp yarns onto a beam which is used during the weaving process. 2. Sectional Warping: Yarns are wound in sections and then combined. It enables better control over tensions and patterns. 3. Direct Warping: Involves feeding yarn directly from cones to the beam, which is faster but may have less control over yarn tension.
Sizing Ingredients
Sizing refers to applying a protective coating to warp yarns to improve their strength and reduce friction. Common sizing ingredients include: 1. Starches: Such as corn or potato starch, providing a good balance of adhesion and flexibility. 2. Synthetic Polymers: Like polyvinyl alcohol (PVA), offering enhanced properties like water resistance. 3. Oils: Sometimes used to reduce friction during weaving. Each ingredient contributes to varying degrees of stiffness, adhesion, and ease of weaving.
Defects in Sizing
Defects during the sizing process can lead to issues in weaving. Common defects include: 1. Poor Adhesion: This occurs when the sizing materials do not bond well with the yarn, leading to flaking. 2. Uneven Coating: If the sizing is applied unevenly, it can result in warp breakage or poor fabric appearance. 3. Excess Sizing: Too much sizing can make the yarn stiff and difficult to weave, resulting in lower fabric quality. Regular monitoring and adjustment of the sizing process are crucial to minimize defects.
Basic Mechanisms of Looms - Loom motions, Tappet shedding, Pick mechanisms
Basic Mechanisms of Looms
Loom Motions
Loom motions refer to the various movements that occur during the weaving process. The main types are: 1. Shedding - the lifting and lowering of warp threads to create a shed for the weft thread. 2. Picking - the insertion of the weft thread across the width of the loom. 3. Beating-up - pushing the inserted weft thread into place against the already woven fabric. Each of these motions is critical for the efficient operation of the loom.
Tappet Shedding
Tappet shedding is a specific mechanism used to create the shed in looms. It operates using tappets, which are rotating elements that lift and lower the warp threads. The tappets are connected to the heddles that hold the warp threads in position. This mechanism is appreciated for its simplicity and effectiveness, allowing for various patterns to be woven based on the tappet design.
Pick Mechanisms
Pick mechanisms are responsible for the insertion of the weft thread into the shed created by the shedding process. Common types of pick mechanisms include: 1. Shuttle - the traditional method where a shuttle carries the weft thread. 2. Rapier - uses a rapier to insert the weft, allowing for higher speeds and flexibility in yarn types. 3. Air jet - utilizes compressed air to propel the weft into the shed, known for its high efficiency and speed.
Weaving and its types - Plain weave, Twill weave, Satin weave, Mock Leno, Honey Comb
Weaving and its types
Plain Weave
Plain weave is the simplest and most common type of weaving. It is created by interlacing the warp and weft threads at right angles to each other, one over and one under. This results in a strong and balanced fabric, suitable for a variety of applications like shirts, sheets, and clothing.
Twill Weave
Twill weave is characterized by a diagonal rib pattern. It is created by passing the weft thread over one or more warp threads and then under two or more threads. This weave type offers more texture and durability and is commonly used for denim, chinos, and home textiles.
Satin Weave
Satin weave produces a smooth, glossy surface on one side of the fabric. It is achieved by passing the weft thread over multiple warp threads before going under one. This technique results in a luxurious feel and is widely used in evening wear, lingerie, and upholstery.
Mock Leno
Mock leno is a weaving technique that creates an airy texture by twisting pairs of warp threads around the weft. This results in an open structure that allows for breathability. It is often used in lightweight fabrics such as curtains and garments requiring ventilation.
Honey Comb
Honey comb weave is a variation of the plain weave that creates a textured surface resembling a honey comb pattern. It involves grouping the warp and weft threads in such a way that forms raised areas. This type is commonly used for dish towels and woven fabrics with decorative purposes.
Loom types - Dobby and Jacquard, Shuttle-less looms - Projectiles, Rapier, Air jet
Loom Types and Shuttle-less Looms
Dobby Looms
Dobby looms are equipped with a device called a dobby that allows for the automatic lifting of warp threads. This technology enables the production of complex patterns and weaves by controlling a predefined number of warp threads. Dobby looms are ideal for creating woven fabrics with multiple designs and textures.
Jacquard Looms
Jacquard looms offer a higher degree of automation compared to traditional looms. They utilize a punched card system that allows for the individual control of each warp thread, enabling intricate designs and complex patterns. They are suitable for producing elaborate fabrics such as brocade, damask, and even detailed images.
Shuttle-less Looms
Shuttle-less looms eliminate the need for traditional shuttles in the weaving process. They enhance speed and efficiency, providing a higher production rate. This category includes several types of shuttle-less looms, each employing different mechanisms for yarn insertion.
Projectile Looms
Projectile looms use a small projectile to insert the weft yarn into the shed. The projectile is shot across the width of the loom, allowing for high-speed weaving. This type of loom is particularly effective for thicker yarns and heavier fabrics.
Rapier Looms
Rapier looms utilize a pair of rapiers to carry the weft yarn across the loom. One rapier picks up the weft yarn and carries it halfway across the width, while the second rapier completes the insertion. This system provides greater control over the yarn and is suitable for a wide range of fabrics.
Air Jet Looms
Air jet looms utilize a jet of air to propel the weft yarn across the loom. This technology allows for very high-speed weaving and is particularly effective for lighter fabrics. Air jet looms are known for their efficiency and minimal mechanical wear.
