Intro to Pressing / Ironing

In order to achieve good pressing quality, there are four basic parameters that need to be controlled to meet optimum performance: heat, moisture, pressure and cooling with vacuum. The importance of each parameter is discussed in the following section. • Heat: Heat is required in most pressing operations to enable the fibers to soften and thus stabilize the garment shape. Temperature selection is of utmost importance, as an incorrect temperature setting can cause damage to fibers and yarns. • Moisture: Moisture is introduced by the use of steam. Steam at different pressures has different moisture contents; the higher the steam pressure, the lower the moisture in the steam. The presence of moisture is required to aid in fiber swelling and thus shape stabilization. Different fibers require different amounts of moisture. For example, natural fibers such as cotton and wool and regenerated cellulose fibers such as bamboo viscose and viscose rayon require the presence of moisture in the steam, and therefore steaming tables are usually preferred. On the other hand, synthetic fibers require heat to promote swelling and therefore relaxation of the structure. Excessive moisture may cause fabric shrinkage and color bleeding. • Pressure: Pressure is applied to the garment during pressing to give good crease retention and permanency. Excessive pressure may result in garment or crease distortion. • Vacuum: Vacuum is applied at the completion of the pressing operation. This draws cool air through the garment, reducing the garment temperature, lowering the moisture content and increasing shape retention. Particularly important for garments made from wool and wool blends, this also applies to cotton and viscose blends with synthetic fibers such as polyester and nylon.

Factors affecting pressing: