Core Structure and Process Applications of Pre‑treatment Combined Machines for Textile Printing and Dyeing

Pre‑treatment in textile printing and dyeing is a foundational process that determines the quality of fabric dyeing and printing. The desizing‑scouring‑bleaching combined machine, as the core equipment, integrates three sequential steps—desizing, scouring, and bleaching—enabling continuous pre‑treatment of greige fabrics and finding widespread application in processing cotton, polyester‑cotton, and viscose fabrics. The entire machine adopts a modular, building‑block design, comprising five major modules: the fabric feeding unit, the padding unit, the steam‑soaking reaction tank, the multi‑section rinsing unit, and the drying‑and‑unwinding unit. Each module is driven by servo‑based synchronous transmission, with tension fluctuations kept within 10 N throughout the process, thereby preventing defects such as wrinkling and weft skew in elastic fabrics.

The pad‑roll unit is equipped with a hydraulic press, and its rubber rollers precisely control the liquor pickup to 45%–65%. A high‑feed vacuum system ensures that desizing and scouring auxiliaries penetrate deep into the fibers, boosting auxiliary utilization by 30% compared with conventional padding tanks while reducing chemical consumption. The steaming box features a sealed, insulated design; saturated steam at 100–102°C maintains a constant temperature for 60–90 minutes, breaking down sizing agents, pectins, waxes, and other impurities on the greige fabric. In the washing section, a staged counter‑current water‑saving design directs clean water into the final tank and discharges wastewater from the first tank, cutting water usage by 85% relative to conventional multi‑stage systems.

The equipment is categorized into two types: flat‑width and rope‑type. Flat‑width machines are suited for high‑density, stretchy, wide‑width home‑textile fabrics, producing finished goods with excellent flatness and no rope‑like creases during processing. Rope‑type machines offer higher throughput and are ideal for mass‑producing bleached fabrics and printed base fabrics; however, they tend to leave creases on heavier materials. In recent years, new‑generation models have incorporated ultrasonic‑assisted cleaning technology, which uses cavitation to remove impurities, boosting whiteness by 3 percentage points while reducing water consumption by 28% and eliminating the need for large amounts of strong alkaline additives—aligning with environmental standards.

The automated control system can store more than 200 process recipes, automatically adjusting machine speed, padding pressure, and steam temperature, and eliminating the need for manual re‑setup when switching fabric types. The process stability of pretreatment equipment directly affects the uniformity of subsequent dyeing; uneven padding or insufficient steaming time can result in color spots and reduced color fastness. Therefore, during equipment maintenance, it is essential to regularly calibrate roller pressure and clean the wash‑water filters to ensure long‑term stable production.