Decoupling wrinkles of plain woven cotton fabrics in washer-dryer: Non-superimposed stage-specific wrinkling mechanisms and a mechanical-temperature change optimization strategy

Conventional understanding in washer-dryers holds that fabric wrinkling might occur separately during the washing and drying stages, and may potentially superimpose. This study established a comprehensive monitoring platform to reveal the wrinkling stages, factors, and mechanisms of plain woven cotton fabrics throughout the entire “washing-spinning-drying” cycle in condensing tumble washer-dryers, and proposed a wrinkle-removal method. The results showed that: wrinkles in plain woven cotton fabrics within washer-dryers primarily form during the later stages of drying when moisture content falls below 30%, while wrinkles from the washing and spinning stages do not superimpose onto the drying stage; load mass, rotation speed, rotating frequency, drying temperature, and fabric moisture content are the core factors affecting wrinkling. A larger load results in smaller fabric movement space in the drum, thus aggravating wrinkles. Drum rotation speed and rotating frequency jointly influence fabric wrinkling by affecting the fabric movement mode, spreading area in the drum cross-section, distribution uniformity in different quadrants, and residence-accumulation time; the optimal mechanical configuration for wrinkle removal is a rotation speed of 55 rpm and a rotating frequency of 27 s/3 s. Low-temperature drying at 60°C leads to mechanical force accumulation from prolonged duration, while high-temperature drying above 90 °C causes uneven fiber shrinkage due to rapid moisture evaporation, both of which induce severe wrinkling. In addition, a “mechanical force-temperature change” collaborative optimization method was proposed for wrinkle recovery. On the basis of the optimal rotation speed and rotating frequency, using a “120 °C rapid water loss in the early stage + 60°C slow recovery in the late stage” mode with 30% moisture content as the dividing point can increase smoothness by 0.7–1.1 grades, and its reliability was verified via shirt wrinkle removal. This study provides theoretical and process guidance for developing wrinkle removal functions in washer-dryers.