For those who are engaged in fabric purchasing, fabric matching or clothing design, understanding the warp and weft density of woven fabrics is very helpful for you to choose fabrics.
Changes in warp and weft density, yarn count and organizational structure have an important impact on fabric style. With the same warp and weft yarn count and weave structure, fabrics with different warp and weft densities have very different styles and appearances. For example, poplin and plain cloth are both plain weaves. The ratio of poplin’s warp density to weft density is 1.8 to 2.2:1. The warp density is significantly greater than the weft density. The surface of the fabric forms a diamond-shaped grain pattern composed of the raised parts of the warp yarns, which creates a drapey feel. Good, rich in feel and vision, clean and smooth cloth surface, fine texture, full grain, soft and lustrous luster, soft and waxy feel, etc. However, plain cloth with the same yarn count (closer in warp and weft density) does not have this effect. The feel is relatively simple. In addition, we analyze the warp and weft density of the fabric, which can be used to calculate its weight and understand whether the fabric has cut corners.
So how can we accurately and quickly read the warp and weft density of a piece of fabric? Some friends may be using a counting convex lens density analyzer. This tool is time-consuming and difficult for people with poor eyesight. Although some convex lenses are equipped with light sources to help with counting. As shown below
However, this kind of analyzer is still quite useful for analyzing fabric structure. For example, the plain structure in the picture below can be seen very clearly.
For those of us who deal with woven fabrics all day long , we don’t need the above analyzer to analyze the longitude and latitude density, because it is too time-consuming and difficult to quickly and accurately analyze the samples given to us by the customers. Generally, when we go to a customer’s place and the customer gives us a piece of fabric, we have to immediately analyze the warp and weft density and structure in order to respond quickly. The tool we use is a density mirror, which can help us read the warp and weft density of woven fabrics within 5 seconds. As shown below
As you can see, this density mirror has a series of numbers listed on the top and bottom. The top number represents the number of lines per centimeter, and the bottom number represents the number of lines per centimeter. is the number of threads per inch. When reading, you can read the numbers on both sides, but the units are different. When choosing a density mirror, you need to pay attention to the approximate density range of the fabrics you usually analyze. As shown in the picture, the density scope has a reading range of 45-160 bars/inch. However, it is generally difficult to read close to 45 bars or 160 bars, so the suitable reading range of this density scope is around 46-150 bars/inch. As for why, we will analyze it later.
Now let’s talk about how to use this density mirror. It’s actually very simple. When you want to read the weft density, you put the density mirror on the fabric along the weft direction, and you will find a diamond shape on the density mirror. The tip of the diamond refers to the weft density, and the upper tip is the number of strips per centimeter. , the lower tip is strips per inch. The conversion results of these two units are the same. As shown in the picture:
Similarly, by placing the density mirror along the meridional direction, the meridional density can be read. As shown in the picture
You can see that the warp density of this fabric is relatively high, about 140 strips/inch. If the density is too high, the rhombus will not easily appear and the reading will be biased. This explains the problem of choosing a density mirror mentioned above.
Some fabrics are easier to read the warp and weft density, such as low-density, light-colored, low-count fabrics, but some fabrics are more difficult to read, such as high-density, dark-colored, and high-count fabrics. In practice, we have summarized an empirical method that can assist in reading the density of this high-density dark cloth, that is, lift the cloth under a light source and put a density mirror on it. The diamond-shaped numbers can be easily read through the light source. As shown in the picture
Finally, when some friends used a density mirror to detect the warp and weft density of the fabric on their hands, they discovered how to measure the density and fabric. The specifications reported by the factory are different, and the differences are quite large. Don’t worry, for fabrics that have been post-processed, the warp and weft density will change. Because the warp and weft directions undergo a series of physical effects, especially shrinkage, it is normal for the warp and weft density to change. For example, the density of our 128*60 cotton twill dyed finished fabric may reach 133*61. So�Consider the impact of finishing and judge fabric quality changes based on weight. </p
