What is the effect of temperature fluctuation on the ironing effect of fully-automatic industry ironing machine?

In the field of textile finishing, the fully automatic industrial ironing machine is a key equipment for achieving fabric shaping, and its ironing effect is directly restricted by the temperature control accuracy. Temperature fluctuation, as a core parameter affecting ironing quality, not only involves the efficiency of heat energy transfer, but is also closely related to the physical properties, chemical stability and final appearance quality of fabric fibers.

At the fiber structure level, temperature fluctuation has a significant impact on the motion state of fiber molecular chains. When the temperature fluctuation amplitude exceeds ±5℃, the amorphous region of cotton fiber will undergo non-uniform deformation, resulting in disordered directional arrangement of local fiber chains. Taking the temperature range of 170℃±10℃ as an example, the crystallinity change rate of cotton fiber can be as high as 12%. This nonlinear deformation not only affects the appearance of the fabric, but may also cause irregular wrinkles on the surface. For synthetic fibers, temperature fluctuations are more likely to cause thermal degradation near the melting point. For example, the molecular chain breakage rate of polyester fiber will increase by 3 times under an environment of 190℃±8℃, resulting in permanent deformation and affecting the service life and performance of the fabric.

In terms of heat energy transfer efficiency, temperature fluctuations will destroy the heat exchange balance between steam and fabric. When the steam temperature fluctuates between 160℃ and 180℃, the temperature gradient between the surface and the inside of the fabric will change significantly. Experiments show that the heat flux density change rate on the fabric surface can reach 0.8W/cm2 for every 1℃ temperature fluctuation. This non-steady-state heat transfer phenomenon will lead to uneven distribution of fabric moisture content. Especially when dealing with heavy fabrics, temperature fluctuations will reduce the penetration depth of steam by 40%, resulting in the "cold" phenomenon of overheating the surface layer while the inside does not reach the plasticizing temperature, which in turn affects the overall quality of the product.

From the perspective of chemical stability, temperature fluctuations will accelerate the thermal decomposition of fabric dyes. When the ironing temperature fluctuates between 150℃ and 200℃, the rate of decrease in color fastness of reactive dyes will accelerate by 2.5 times. Especially for dark fabrics, when the temperature fluctuation exceeds ±7℃, the change rate of its K/S value (color depth index) can reach 15%, which will directly lead to obvious color difference in the fabric. In addition, the sublimation rate of disperse dyes at high temperatures is exponentially related to temperature fluctuations. For every 5°C increase in temperature, the sublimation amount will increase by 40%, causing the "floating color" phenomenon on the surface of the fabric, reducing the market competitiveness of the product.

In terms of mechanical properties, temperature fluctuations will also significantly affect the dimensional stability of the fabric. When the ironing temperature fluctuates within the range of 165°C ± 9°C, the warp shrinkage of cotton fabrics will increase from 2.1% to 3.8%, while the change in weft shrinkage is more significant. This non-uniform shrinkage will destroy the warp and weft balance of the fabric, resulting in a width deviation of more than 0.5cm. For elastic fabrics, temperature fluctuations will cause their elastic recovery rate to decrease by 18%, while the permanent deformation rate will increase by 25%, which will seriously affect the wearing performance and comfort of the fabric.