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Denim Fabric Defects Reference Guide

Common denim fabric classification

 denim fabric can be divided into plain weave, twill weave, slub, etc. due to their different production processes, as shown in Figure 1.1. In terms of the ingredients contained in denim fabric, denim is divided into combed and carded, 100% cotton, cotton and linen blended with Lycra, etc. At present, the market is mainly popular ring yarn denim, warp and weft slub denim, overcolor and assorted denim, etc.

Figure 1.1 Types of Denim Fabric

Figure 1.1 Types of denim fabric

Traditional denim vs. generalized denim

 Traditional denim is a right twill fabric, which is made of indigo-dyed cotton warp yarns and white weft yarns interlaced three times. The woven yarn is woven with pure cotton natural fiber. The denim fabric has strong moisture absorption, good air permeability and no irritation to human skin. At the same time, indigo is a coordinated color that can match other colors. The thick special warp yarns are interwoven, and the color floats of the warp yarns and the white floats of the weft yarns are matched in proportion to form a cloth with clear blue and clear texture. In addition to the use of pure cotton yarn, denim fabric in a broad sense also use other fibers or synthetic fibers. The dyeing of warp yarns has also got rid of the traditional single indigo dyeing, and a variety of colors have appeared, making denim fabric from a single raw material, thick and single tone. Varieties are developing in a multi-variety and multi-color direction.

 Characteristics of denim clothing

Due to factors such as raw materials, yarn characteristics, weaving methods, etc., the use of different processing techniques will cause denim fabric to have different appearance characteristics. The denim fabric is woven with coarse special yarn, and the finished product is thick and heavy. When tailored as a garment, the garment has a three-dimensional shape, unlike other fabrics, which is soft; at the same time, the denim fabric is wear-resistant, cost-effective, and is loved by consumers.

Common defect types of denim fabric

Denim fabric is a fabric that is woven with warp yarns dyed and sizing with indigo dye. In the production process of denim fabric, defects may occur in any process. The main defects of denim fabric are shown in Table 2.1.

Denim fabric defect types Defect specific names Causes and appearance
Raw yarn defects Thick warp One warp is thicker than others
Thick weft A weft yarn is thicker with faint white streaks
Uneven yarn The cloth surface is unevenly wavy, with faintly visible nodular white marks
White star defects on cloth The neps and impurities on the weft yarn are woven into the cloth, and the cloth surface shows white star defects
Dying defects Shade bar The cloth surface shows traces of different shades of color in the weft direction
Color difference between head and tail Color difference between cloth head and cloth tail
Warp color streak The fabric has a dark or light streak in the warp direction
Weaving defects Weft crease When the loom is turned on, there are continuous streaks in the weft direction on the cloth
Warp break One or more warps are missing in the warp direction of the fabric
Weft missing Missing a weft in the twill weave
Disorder warp and weft The warp and weft yarns on the cloth are in disorder
Finishing defects Uneven singeing Uneven singeing, feather-like warp stripes
Edge color difference There are obvious differences in color on both sides of the cloth edge

Table 2.1 main defects of denim fabric

Table 2.1 shows the causes and manifestations of denim fabric defects. Starting from the causes of defects, preventing denim fabric defects will help improve the grade of denim fabric, reduce the cost of later manual inspections, and improve corporate efficiency.

Analysis of defect characteristics of denim fabric

From the previous chapter, we know that in the process of denim fabric production, defects may occur in any production process. Defect detection is an important part of denim fabric production and quality management. At present, manual inspection is easily affected by subjective factors and lacks consistency. At the same time, working under strong light for a long time has a greater impact on workers’ eyesight.

Due to the wide variety of defects and diversified shapes, the denim fabric image data set in this paper uses high-definition denim images collected by the first-line textile workshop. There are 9576 images in total, including 5913 images with defects and 3,663 images without defects. Including defects such as knots, three threads, holes, oil stains, etc., the defect data of denim fabric is manually confirmed by experienced fabric inspectors and manually marked. The image resolution is 2446*1000, the feature details are clear, and the corresponding xml format information is generated file. The data set covers all kinds of important defects in denim fabric, and each image of denim fabric contains one or more defects. Common defects in denim fabric are shown in Figure 2.2 below.

Fig 2.2 Common defects of denim fabric-1

Fig 2.2 Common defects of denim fabric

Fig 2.2 Common defects of denim fabric

 

Perform statistical analysis on the denim fabric data set. The statistics of various defects are shown in Table 2.2, and the statistical graph of the denim fabric defects is shown in Figure 2.3.

Defect name Count (pcs) Defect name Count

(pcs)

Defect name Count

(pcs)

Defect name Count

(pcs)

Cloth slot 1528 Break warp 243 Weft missing 106 Reed Mark 64
Trash fiber 1037 Pulp spot 234 Dead wrinkle 100 Slippage yarn 63
Thick weft 646 Stains 233 Oily 98 Bad weft 56
Broken spandex 317 Thick warp 213 Slippage star 93 Uneven singeing 50
Hole 305 Slub 174 Repair mark 78 Wavy shading 36
Loose warp 297 Piercing 148 Rubbing crease 74 Color difference shading 26
Piercing 283 Stretched warp 143 Filling floats 69 Double weft 14
Hiding shading 262 Flower springboard 109 Water stain 69 Clouded thick and thin yarn 11

Table2.2 Statistics of denim fabric defects

Testing standards on denim fabric

ASTM D6554 / D6554M – 14 Standard Specification for 100 % Cotton denim fabric

Denim Fabric Testing Requirements from ASTM D6554 D6554M

Contact us to get the free Pdf standard.

 

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