How a pre-shrinking machine works

A pre-shrinking machine is a type of shrinking machine with four primary functions. Function 1: Fabric shrinkage treatment—this process softens untreated fabric and stabilizes its original dimensions by adjusting the slant of the yarns, thereby minimizing shrinkage that typically occurs during sewing and ironing.

2. To prevent size changes or alterations in the garments being made, you can avoid accounting for fabric expansion and shrinkage during the clothing production process—allowing you to focus solely on your design. After shrinkage treatment, the fabric becomes dimensionally stable, offers a pleasant hand feel, and remains resistant to shrinking even after re-ironing. This treatment significantly enhances product quality, adding substantial value. Moreover, this shrinkage machine is essential for modern, computer-aided design and computer-aided manufacturing systems that rely on automated equipment.

The wet-heat pre-shrinking machine is primarily used to pre-shrink fabrics made from cellulosic fibers such as cotton, linen, silk, and viscose. These fabrics are highly absorbent, causing the fibers to swell easily, which in turn reduces their length and subsequently compromises the dimensional stability of both the fabric itself and any blended textiles derived from it. The basic process of a wet-heat pre-shrinking machine involves wet spraying, squeezing, and drying. Depending on the coating material used, the equipment can be categorized into two main types: rubber blanket pre-shrinkers and felt blanket pre-shrinkers. Both operate based on the principle of "bending, deformation, and compression."

A pre-shrinking machine refers to a finishing process that uses physical methods to reduce fabric shrinkage after immersion in water; it is also known as mechanical pre-shrinkage treatment. During the dyeing and finishing process, the fabric experiences tension along the warp direction, which reduces the height of the bending waves in the warp yarns, leading to elongation. Meanwhile, when hydrophilic fiber fabrics are soaked in water, the fibers swell, causing both warp and weft yarn diameters to increase. This expansion intensifies the height of the warp bending waves, thereby shortening the overall length of the fabric and resulting in shrinkage. The percentage by which the fabric's length is reduced relative to its original length is referred to as the shrinkage rate.

Mechanical pre-shrinking involves wetting the fabric by spraying steam or mist, followed by applying mechanical pressure along the warp direction to increase the height of the crepe waves. The fabric is then loosely dried afterward. Additional data: Fabric pre-shrinking is typically carried out using a mechanical pre-shrinking machine. The primary purpose of pre-shrinking with this machine is to achieve stable fabric dimensions, with a general requirement that shrinkage in both the warp and weft directions remains below 3%. Beyond ensuring dimensional stability, this process also enhances the fabric’s hand feel and visual appeal, helping it meet specific weight and stiffness requirements. Mechanical pre-shrinkers are especially suited for fabrics made from cellulosic fibers such as cotton, linen, silk, and viscose. These fibers are highly absorbent, causing them to swell significantly when exposed to moisture, which in turn reduces their length—and ultimately compromises the dimensional stability of both the pure fibers and their blended fabrics.