Residual foaming agent content and water content are the dominant factors influencing surface roughness of the pattern. Through extending drying time of bead and forming steam time

increasing steam pressure as well as decreasing water cooling time

water content in the pattern can be dropped

and pattern with smooth surface can be observed. However

bead is collapsed with excessive drying time and steaming time and excessive short water cooling time as well as excessive high foaming pressure

resulting in the increase of surface roughness due to the formation of wrinkle as a result of surface collapse of pattern.