Warping is a process in which a certain number of warp yarns are arranged in a predetermined length and width according to the requirements of the process design, and are wound in parallel on the warp beam or the weaving shaft with uniform tension. The warping process causes the warp yarn package to be changed from a winding cylinder to a warp beam or a weaving shaft. The so-called warp beam means that the weaving shaft needs to be formed by the sizing process. The so-called weaving shaft means that the yarn shaft formed by warping is directly supplied to the threading process, and does not need to go through the sizing process.
The warping quality is of great significance for ensuring the smooth progress of the subsequent processing steps and good fabric quality. Therefore, the general requirements for the warping process are as follows:
(1) The tension of the single warp and the warp of the whole warp should be as uniform as possible to form a cylindrical yarn shaft with a uniform width and hardness, thereby reducing warp yarn breakage and fabric quality during weaving.
(2) The warp yarn must have proper tension, and should maintain its strength and elasticity, and should not deteriorate the physical and mechanical properties of the yarn.
(3) The arrangement and winding density of warp yarns on the warp beam are uniform, and the warping shaft package surface is smooth and flat.
(4) The number of warping, warping length, yarn configuration and arrangement shall comply with the process requirements.
(5) The joint quality should meet the specified standards.
(6) Improve the warping productivity as much as possible and reduce the yarn return.
In some cases, there are some special requirements for the warping process. For example, in the yarn dyeing production, if the warp beam is directly dyed, in order to facilitate the uniform penetration of the dyeing liquid, the warping shaft is required to be soft. In the production of certain industrial fabrics, in order to reduce the residual elongation in the fabric, it is necessary to subject the yarn to a special elongation of 3% to 4% during warping.