Abstract: It is difficult to determine the radial length of extrusion area for rubber blanket pre-shrinking machine when preshrinking for special construction of two interactional cylindrical rollers. It causes some difficulties to online estimation of shrinkage. Analyzing deformation process of rubber blanket when it is extruded and making some simplifications, a mathematical model of radial length of rubber blanket in extrusion area when extruding was established to solve the problem according to Hertz contact theory. The result of application indicates that the relative errors of radial length calculated by the model are all less than 4%, and the mean absolute percentage error is about 2%. The model is efficient. It provides theory reference for online estimation of shrinkage in practical production.

Key words: dyeing and finishing, rubber blanket preshrinking, Hertz contact theory, radial length