In the setting machine, the chemical structural formula of cellulose is repeatedly composed of α glucose as a basic structural unit, and its elemental composition is carbon 444%, hydrogen 17%, and oxygen 49.39%. The degree of polymerization of cotton fibers is between 6000 and 11,000. Cotton fiber is a porous material, and there are many hydrophilic groups (-OH) on its cellulose macromolecules, so it has good hygroscopicity. Under normal atmospheric conditions, the moisture regain of cotton fibers can reach about 5%. The cross section of the cotton fiber is composed of many concentric layers. If the garment is washed and washed with water and molecules on the cellulose to form a macromolecular cluster of cellulose + water, the inner holes are filled with water molecules and cellulose molecules, the fiber structure changes, and the length is shortened It becomes thicker in the horizontal direction, and it is also wrinkled. The shuttle rate of a fabric depends on many factors: raw material properties, twist, fabric shuttle position, etc. Of course, it is also necessary to manually control the shrinkage rate. Many customers have requirements on the weight and shuttle of specific products, but white billets are not the same. That way, artificial shuttle rate interference can be carried out before the fabric is dyed and finished.