What is Denim Fabric?
Denim is a sturdy, hard wearing and durable warp faced 3/1 twill cotton fabric, having weights of 14½ ounces per square yard, traditionally woven with indigo dyed warp and white filling yarns. It is the most popular fabric, no such fabric become popular like denim. Denim fabric is renowned for its ruggedness and ability to withstand wear and tear, making it a popular choice for workwear, casual clothing, and fashion items. The future of denim is secure as it has an ever growing fashion appeal internationally among all age groups. Somehow it remains eternally young in the hearts of generations and is now the fabric of choice for manufacturing anything that can be worn by anyone, anywhere, at anytime.
The name ‘denim’ originated from the city of Nîmes in France, where serge de Nîmes was made. Denim is produced using a vat color, indigo, which is connected to cotton fabric in an inexactly held structure in layers. The manufacturing process of denim is similar to that of grey fabric up to the process of weaving, with the main difference that in the case of denim fabric, it is dyed at the stage of sizing, whereas in the case of grey fabric, the decision regarding the dyeing stage depends on the finished product. The details of each process are given in the flowchart.
Flowchart of Denim Fabric Manufacturing:
Spinning
↓
Bale warping
↓
Rope dyeing
↓
Long chain beaming
↓
Sizing
↓
Weaving
↓
Finishing
↓
Inspection & folding
↓
Packing
↓
Dispatch
All manufacturing process of denim fabric are descried briefly:
Spinning:
The beginning phase of denim fabric manufacturing is opening and blending. Opening starts with baled cotton fiber being isolated into little tufts. A mix of cotton strands is made on every opening line.
Cotton is conveyed via air suction from the opening and blending lines through extra cleaning and mixing machines, to the cards. The real functions of carding are to expel remote matter and short filaments, shape the cotton into a web, and change the web into a rope-like structure known as a bit.
The drawing procedure delivers a solitary, uniform fragment from six card bits. The extra mixing, paralleling of filaments, and cleaning in this procedure deliver a bit for open end and ring spinning. For ring spinning, the bit must go through an extra procedure called roving.
Cotton fibers are framed into a yarn by diffusive activity in open-end spinning. Singular fibres are laid down in the groove of a fast-spinning rotor and twisted into yarn. After the cotton strands are spun into yarn, the yarn is twisted into an expansive bundle.
Fabric Weaving:
Grey yarn on cones:
Ordinarily yarns obtained for weaving in cone structures are either from ring turning or from open-end turning in single or twofold overlap as required. For weaving, the yarn is classified into:
- Warp
- Weft
Normally, to weave, yarn used as twist ought to be adequately solid to withstand stretch and strains applied amid weaving operations. Thus they have count strength product and are further measured to build quality. The weft yarn is used straightforward on weaving machines and, if required, is also rewound to upgrade its execution in weaving.
Warping on sectional/direct warping:
The twist yarn needs to be made into a sheet structure for the weaving machines. At twisting, the individual cones are put into the creel (the quantity of cones relies on fabric development) and yarn from individual cones is pulled together into a sheet structure, twisted on a barrel called distorting shafts (for direct distorting) or on weaving bars (for sectional warping). Ordinarily if the twist sheet has various shaded yarns it is prepared on a sectional distorting machine.
Sizing of yarn in set/beam to beam position:
The object of sizing is to enhance the quality of the yarn by synthetically restricting the filaments with each other, enhancing its grating resistance limit by artificially covering the surface of yarn/strands. Furthermore, the number of strings in the wrapper’s shaft sheet is less than against the number of strings required in the entire width of fabric. Subsequently sheets are duplicated by drawing yarns together from numerous twist shafts; one sheet is also made on the measuring machine. Approximately 8%–12% size material on twist string is regularly connected. This change in quality and frictional resistance that is normal for twist yarn is crucial because during weaving, yarn experiences serious strain, push and frictional operations.
Drawing-in:
Weaving is fundamentally the interlacement of two sets (i.e., twists and weft) of strings in a desired arrangement. To achieve this interlacement, the twisted yarn sheet is bifurcated and opened as two layers per sheet and the weft string is embedded into the two twist sheets. This operation is called shedding. To perform shedding the twist yarn should go through the heald eyes of the heald shafts. This operation is known as drawing-in.
Beam gaiting or knotting on a loom:
The drawn weavers beams are settled on weaving machines, strings are tied and head shafts are coupled. This operation is called beam gaiting. On the off chance that undrawn twist strings are hitched directly to the strings of completed bars, it is called knotting. These operations are crucial because ordinarily a weavers pillar can convey just a certain length of twist sheet on it, and so when it is woven, the entire length is becomes the fabric by the weaving machine. A further twist length is required to be sustained, which should be possible by tying or gaiting different bars on the weaving machine.
Weaving:
Weaving is interlacing two sets of yarn and making fabric. One set is called the warp, which is in the sheet frame; the other one is called the weft, which is embedded between two layers of warp sheet by a method for an appropriate carrier (i.e., shuttle, projectile, rapier, air current, water current and flow, and so on). The distinctive types of technologies accessible for weaving machines are:
- Conventional shuttle weaving system by ordinary looms or automatic looms
- Shuttleless weaving system by air jet/water jet/rapier/projectile
A shuttle loom is technology with significantly less generation by virtue of its slow speed and excessive wear and tear of machinery. The shuttle loom is now out of date. Denim is woven through a shuttleless weaving system like as air jet looms, rapier looms or projectile looms.
Finishing:
Grey fabric:
Woven fabric or grey fabric, as it is famously called, is wound on a cloth roll and is taken from weaving machines at specific intervals and checked on inspection machines for conceivable outcomes of any weaving deficiency. If such defects are seen anywhere in the fabric during review, certain remediations are taken at weaving, warping, sizing, and so forth. This is a quality control exercise.
Denim fabric:
Denim fabrics woven of 100% cotton would be exceptionally solid and strong. Generally blue denim is twist-confronted cotton fabric with 3 × 1 twill development with the twist coloured in a strong shading and the weft left uncoloured. The look and nature of the denim fabric should be enhance subsequent to colouring, the procedure of which varies from plant to plant. Typically the procedure of colouring manages the innovation of denim assembly.
Colouring of denim fabric happens at the sizing stage. There are well-known techniques for colouring denim fabric:
- Rope dyeing
- Sheet dyeing
An organization can use any of the strategies. In nations such as India, sheet dyeing is normally used to assemble its denim fabrics, which has the following advantages over rope dyeing:
- The innovation requires less capital venture.
- The innovation is demonstrable.
- The expense of generation is lower.
- The process time is lower.
- Sheet dyeing machines are easy to work with.
- The main problem with sheet colouring is that there is an issue with choosing the selvedge shade variety.
Sheet dyeing process:
This procedure disposes of a few in-between procedures of rope dyeing. The yarn sheet is washed with chemicals such as caustic and washing soda, and after squeezing the excess water out, the yarn sheet is allowed to pass through dyeing troughs one time for oxidation and the development of dye on yarn. After colouring, the coloured yarn is washed again with water two to three times and finally is pressed before it goes through six drying chambers. The coloured yarn enters a starching gadget and the measuring is finished. After measuring, the estimated twist shaft enters weaving. After weaving, the woven denim fabrics undergoes different completing procedures composed of brushing, searing, washing, impregnation for dressing and drying. Brushing and singeing should eliminate impurities and help to even out the surface of the fabric. Dressing controls the hand and inflexibility of the fabric whereas compressive contracting manages its dimensional dependability.
Indeed, denim fabric without indigo dyeing is not called reliable denim. At first, when denim fabric entered the style market, denim makers used natural indigo dye, which was excessive and gave a characteristic finish. Although synthetic indigo dye has progressively replaced natural indigo dye, some manufacturers still incline toward the natural dye and charge more because they market them as have used a ‘natural dye’.
Making up:
Weaving of fabrics on such multiple sizes is not efficient; subsequently a standard width of fabrics is then forwarded to making up. Fabrics are cut into the necessary width according to estimates required for the machine. Denim fabric and grey fabric are checked for different sorts of imperfections:
- Weaving defects
- Uneven dyeing
- Bleaching and dyeing defects
- Oil stains
- Patches
The last item is classified as a quality problem. The items then determined to be acceptable are isolated and sent to the bundling division while deficient ones are sent for rectification. After assessment, the sets are wrapped with polythene covers and sent for dispatch according to the purchaser’s needs.
Dispatch:
Rolls and sets framed and pressed according to the purchaser’s prerequisites are then sent for final dispatches.
Washing:
Denim washing is a pivotal stage in denim fabric manufacturing, encompassing techniques like stone washing, acid washing, enzyme washing, and various finishing processes to impart specific visual, tactile, and structural characteristics to denim garments. These processes range from creating distressed and faded appearances to softening the fabric and enhancing comfort, allowing manufacturers to achieve diverse styles and textures in denim fashion while, in recent years, emphasizing sustainable practices to minimize environmental impact.
Conclusion:
Denim fabric manufacturing process is a complex and multi-step procedure that transforms raw cotton into the iconic denim materials used in various fashion items. Each step plays a crucial role in determining the quality, appearance, and characteristics of the final denim product. Advances in technology and sustainable practices have also been integrated into this process to meet the demands of modern consumers and reduce environmental impact.
References:
- Denim : Manufacture, Finishing and Applications. Edited by Roshan Paul
- Sustainability in Denim. Editors: Subramanian Muthu
- Kiron, Mazharul Islam “Denim Jeans Production Process” https://textilelearner.net/denim-jeans-production-process/ Accessed at 28/09/2023
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