Shearing and cropping process of fabric
Grey fabric comes from the weaving department and when it is ready for chemical processing, it is extremely necessary to prepare fabric for that process. Therefore stitching action comes first, preparing fabric for further process. After stitching it is vital that remove the extra yarn from surfaces and that's why sharing or cropping happens.
Stitching
After the weaving department, the fabric comes to the stitching department. The fabric received from the weaving department is about 60 to 200 meters, however, we know textile wet processing is a continuous process so the fabric length should be several thousand meters for the fabric pieces to be stitched together.
Stitching is also known as batching because we are stitching the batches of fabric lots as per the requirement. Small lots or collections are stitched together to form a large batch of fabric. Stitching is done with the help of a sewing machine.
Object-
1. To combine small batches of fabric lots and convert them into long/large batches.
2. Due to large batches the fabric processing will be continuous.
Shearing & cropping
The process of cutting loose and long yarn from the surface of the fabric with the help of (2 or 4)blades is called shearing and cropping. The yarn up to 8 cm in length can be cut in this process.
In the above picture, we can see that the fabric has long threads up to 8 to 10 cm which will affect the further processing so removal of these threads should be done.
Object -
1. To remove long threads which are originated from the fabric surface.
2. To remove the cotton dirt or lint which is mechanically deposited on the surface of the fabric.
3. If any metal impurities are detected then they will be removed manually.
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| Shearing from the fabric |
However, shearing is not only vital for good appearance but also for preparing fabric for further process. and somehow if we fall then process quality can be determined as below mentioned.
In case the bleaching process is done without shearing
Bleaching is done to the entire mass of the fabric and due to long & loose threads the mass of the fabric will be increased hence the chemical requirement in bleaching will be increased
● If some metal impurities are present on the surface of the fabric then they can be stuck to the soft rollers in the machine and with their sharp edges can cut the whole fabric which results in a great loss for the processor
● If metal impurities are catalytically acceptors then the bleaching agent may damage the fabric surface.
In case of dyeing process is done without shearing
● Dying is done to the entire mass of the fabric and due to long and loose threads the mass of the fabric will be increased hence the dye quantity requirement will be increased
● If some metal impurities are present on the surface of the fabric then they can be stuck to the soft rollers in the machine and with their sharp edges can cut the whole fabric which results in a great loss for the processor
● It will result in faulty dyeing
In case the printing process is done without shearing
Due to long and loose threads on the surface of fabric print defects like blank lines, uneven prints are produced on the surface of the fabric
● If some metal impurities are present on the surface of the fabric then they can be stuck to the soft rollers in the machine and with their sharp edges can cut the whole fabric which results in a great loss for the processor
● It will result in faulty printing
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| Fabric without shearing and cropping |
The function of elements in shearing and cropping machine-
1. Metal Detector -
A metal detector is at the entry of the fabric in the machine which detects if any metal impurities or particles are present in the Fabric.
After detecting metal impurities machine will automatically stop to prevent damage to the fabric If these metal impurities or particles are allowed to pass to the next process then it will create many problems by sticking to the rubber rollers These metal particles or pieces have sharp edges which cut or tear the fabric while passing through the rollers.
These metallic particles may be catalytically accelerators to the bleaching agents like sodium hydrochloride(NaOCl) and hydrogen peroxide(H2O2) which may damage the fabric.
2. Brush rollers- (pair of brushes used) -
The fabric passes through the pair of nylon brushes which will remove the loose threads present on the fabric and also remove the loose threads which are mechanically deposited on the fabric surface. It removes the dirt and lint present on the fabric surface.
3. Speed of machine-
Modern shearing and cropping machine speed is up to 120 meters per minute and the average speed is up to 60 meters per minute.
4. Seam detector-(seam means crimps or shrinks in fabric) -
During stitching, if the stitching operation is not done properly then that stitched portion of the fabric looks like it has shrinkage or crimps on the surface of the fabric and this is known as a seam.
This seam is detected by the detector and the machine will get automatically stop then the worker will restitch it with the stitching machine and start the machine.
5. Shearing and cropping rollers -
The long protruding threads which originate from the fabric surface are cut by using blades. Four to six cutter machines are also available which have more efficiency so that the quality of the fabric will be good.
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| Fabric shearing machine |
Questions -
- What if sharing and cropping are not done?
- What is stitching action?
- Objectives of stitching and sharing.
- What is the function of shearing machine parts?
References
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Arputharaj, A., Raja, A. S. M., & Saxena, S. (2016). Developments in sustainable chemical processing of textiles. In Green Fashion (pp. 217–252). Springer Singapore.
Cenite, M. (2015). Google Books. In The SAGE Guide to Key Issues in Mass Media Ethics and Law (pp. 847–858). SAGE Publications, Inc.
Chemicals used in textile processing. (2013, January 10). OEcotextiles. https://oecotextiles.blog/2013/01/10/chemicals-used-in-textile-processing/
Chemistry of textile manufacturing. (2014, April 29). Worldofchemicals.com; Worldofchemicals. https://www.worldofchemicals.com/448/chemistry-articles/chemistry-of-textile-manufacturing.html
Get to know about chemical processing of textile materials. (2022, May 10). ECHEMI. https://www.echemi.com/cms/640314.html
Kan, C.-W. (2015). Plasma treatments for sustainable textile processing. In Sustainable Apparel (pp. 49–118). Elsevier.
Textile School. (2010, November 10). Fabric wet processing techniques. Textile School. https://www.textileschool.com/343/fabric-wet-processing-techniques/
textileblog. (2020, June 19). Stages of wet processing in textile industry. Textile Blog. https://www.textileblog.com/stages-of-wet-processing-in-textile-industry/
Vigo, T. L. (2014). Textile processing and properties: Preparation, dyeing, finishing and performance: Preparation, dyeing, finishing and performance (1st ed.). Elsevier Science & Technology. https://www.elsevier.com/books/textile-processing-and-properties/vigo/978-0-444-88224-0?country=GB&format=print&utm_source=google_ads&utm_medium=paid_search&utm_campaign=ukshopping&gclid=CjwKCAiAhqCdBhB0EiwAH8M_Gn3kr_d2paqVzccxckWobOsLcwl0cD_Mu6vA5I-eqFARiZwx32eUOxoC-LMQAvD_BwE&gclsrc=aw.ds
(N.d.). Textilelearner.net. from https://textilelearner.net/flow-chart-of-textile-wet-processing/
Writer - Rushikesh Patil (Textile Engineer)
