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Quality control and quality assurance in the apparel industry
Interlinings, also called interfacing, are generally nonwoven fabrics that add more structure and body to garment components like collars, button plackets, waistbands, and cuffs. Interlinings may be fusible or sew-on. Interlining fabric durability is important for garment construction. Fusible interfacing can become unglued from fabric and shift, creating rippling, puckering, and unevenness. Hence, the fusible interfacing should be tested for their performance for defects such as cracking, bubbling, and delamination during their regular use. Fusible interfacings are susceptible to the adhesive bleeding through causing darker spots on the surface called strike-through. Fusible interlinings are assessed for their ability to stay bonded to the fashion fabric and not shift during wear and cleaning. They are also tested for compatibility and shrinkage. Compatibility indicates good drapability, bulk, and support of the fabric at the attachment point. Shrinkage can cause puckering of the attached point and bubbled appearance. The three parameters such as temperature, pressure, and time should be appropriately selected to avoid improper interlining attachment.
However the quality of the face fabrics and non woven interlining used in making samples does not always conform to the materials delivered for production. The face fabrics and their interlinings must therefore be tested again to verify the previously accepted fusing parameters.
One of the first successful applications of nonwovens was as interlinings for clothing (Assent, 2003). Nonwovens are still widely used for this purpose but are also used as the main material for protective clothing (Haase, 2003) and increasingly as the outer layer in fashion-based and technical garments (University of Leeds, 2007). The making-up of nonwovens is therefore an important consideration. Patterning, cutting and joining are considered very basically here.
Nonwovens for interlinings are processed in such a way as to give them an adhesive surface. The patterns for these nonwovens are designed and made together with the patterns for the upper fabric and garment lining during the pattern design and grading stages. Table 8.2 outlines the functional aspects of nonwovens that impact on their performance as interlinings, and highlights the stages of fabric production that affect these aspects.
Fusing of interlinings in garment manufacturing is a very important process. Interlinings are the accessories used between two layers of fabric to keep the different components of apparel in a desired shape or to improve the aesthetics and/or performance. Generally, interlinings are soft, thick, and flexible fabric made of cotton, nylon, polyester, wool and viscose or their blends, which may be coated with some resins. There are two types of double dot non woven interlining in use in the garment production: fusible and non fusible. The interlinings are carefully selected so that they can withstand the conditions during the fabric care and maintenance without any damage during the useful life of a garment. Once the garments are finished and inspected, they are packaged and transported to the retailers or the point of sale to the consumers.
The garment construction and type, notably the number and type of seams, linings and interlinings as well as cut and style, clearly play a significant role in the draped appearance of the garment, the presence, nature and bonding of interlinings, etc. having a major effect. So too will the fabric colour, depth of shade and pattern have a significant effect, although these effects are essentially optical in nature and not due to actual changes in the fabric drape per se. With respect to the effects of seams, including seam and stitch type, these have been studied and reviewed in detail by Chung,12 Hu17 and Sharrouf,36 their main effects being on the stiffness (both bending and shear) of the fabric in their immediate vicinity and on their positioning within the garment.
The garment construction and type – notably the number, positioning and type of seams, linings and interlinings – as well as cut and style, play significant roles in the draped appearance of the garment, with the presence, nature and bonding of interlinings having a major effect. Fabric colours, depths of shade and patterns also have significant effects, although these are essentially optical in nature and not due to actual changes in the fabric drape per se. Seams mainly affect fabric stiffness (both bending and shear) in their immediate vicinity, the magnitude of the effect depending on their positioning within the garment. For example, bending length tends to increase with the insertion of a vertical seam, while drape coefficient increases with the addition of radial seams, and increasing the seam allowance has little effect.
The most important factor for performing qualitative fusing is temperature. It must correspond to the glue line temperature, required for the certain interlining. However, the temperature setting or reading on the control panel of a fusing press indicates its belt temperature, not the temperature applied to the interlining. The real temperature that will be delivered to the interlining through the face fabric can be determined only during the test. It can be performed putting special temperature control tape in-between the face fabric and its interlining sample and fusing them. The colour of the tape will show the real temperature applied to the interlining. The optimal fusing temperature must be found for every fabric of the order to avoid its shrinkage or damaging during the fusing process.
Normal cotton sheeting fabrics were applied with a layer of adhesive that can be fixed to the shell fabric by application of heat or pressure. This formed a composite part of the fused shell part and supported the outer shell for better drape and look.
Woven interlinings are majorly 100% cotton based with a thread density of variable count as required for the weight or stiffness needed for a particular use. Now poly-cotton blends are also available to overcome the problems of shrinkage faced in cotton fabrics together with a variety of warp and weft combination like rayon, texturized poly and wool etc.
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