Structural Principles of Stretching and Setting Machines and Key Points for Intelligent Energy-Saving Retrofitting

The stretching and setting machine is a core piece of equipment in post‑dyeing finishing. After dyeing and printing, the fabric undergoes setting treatment to achieve width calibration, thermal shrinkage stabilization, and improved hand feel; it can also integrate functional finishing processes such as water repellency, antibacterial treatment, and softening, directly determining the dimensional stability and visual quality of the finished product. The entire machine is divided into four sections: the feed roller, the pre‑drying zone, the high‑temperature setting oven, and the cooling and delivery section. Fabric grippers on a chain clamp both edges of the fabric, gradually widening it to the standard width, followed by high‑temperature setting at 180–220°C to relieve internal fiber stresses.

Traditional setting machines are extremely energy‑intensive, with hot air from the drying oven vented directly to the atmosphere, resulting in significant heat loss. The blowers use conventional induction motors, leading to substantial electricity waste. The new generation of energy‑efficient models has undergone multiple upgrades: they are equipped with an exhaust‑gas waste‑heat recovery system that preheats incoming fresh air using high‑temperature exhaust from the oven, boosting thermal efficiency to 92% and reducing steam consumption by 35%; the circulating fans have been replaced with permanent‑magnet synchronous motors, cutting power usage by more than 5%, and are paired with variable‑frequency drives that automatically adjust airflow based on the fabric’s moisture content, thereby eliminating unnecessary energy consumption.

The electronic control system is equipped with an online weft density and fabric width sensor, providing real-time feedback on fabric width and automatically adjusting the tension of the cloth clamps, keeping fabric width deviations within ±0.5 cm. Intelligent zone‑based temperature control divides the oven into 6 to 12 independent heating zones: delicate, lightweight fabrics are set at lower temperatures for gentle shaping, while heavyweight denim benefits from elevated temperatures in the higher‑heat zones, preventing brittleness and yellowing. The calendering unit features low‑residue polyurethane rollers, minimizing moisture pickup and reducing the drying load.

In daily operations, cleaning the chain‑type cloth clamps is critical; residual sizing and dyes can lead to edge staining and clamp‑related shutdowns. The waste‑heat recovery filter should be cleaned weekly to prevent clogging and maintain heat‑exchange efficiency. The equipment supports industrial‑Internet connectivity, enabling production data to be synchronized with the factory’s central control platform, where electricity and steam consumption per ton of fabric are tracked, allowing process parameters to be optimized and production costs reduced. Driven by the dual‑carbon policy, energy‑saving retrofits for aging setting machines have become an essential need for textile‑printing and dyeing enterprises; such upgrades typically recoup their investment within one to two years through energy savings.