Modified Design And Dynamic Characteristic Research On Blanket Cylinder Of Offset Press

The bended vibration of printing cylinder caused by cylinder gap impact is bad for printing quality. This paper studies on the blanket cylinder of sheet-fed offset press, modifies the cylinder structure to reduce the bended vibration when the cylinder gap impact occur and researches the static, dynamic characteristics of this cylinder. The main contents and innovations are as follows:1. A shock absorption scheme, by filling the cylinder with shock absorption material, is selected according to the structure characteristic and work condition of the blanket cylinder. The shock absorption material is foamed aluminum with damping capacity.2. With a view to the selected shock absorption scheme and the dimension data of the blanket cylinder in existence, the modified cylinder's dimension data is calculated base on the design targets including cylinder weight, anti-bending stiffness and eccentricity by developing application with Visual C++ 6.0 .3. The solid model of the modified blanket cylinder is established and the static characteristics especially the anti-bending stiffness are researched to contrast with those of the cylinder in existence.4. The finite element method (FEM) model of blanket cylinder is set up and then the mode analyzing on cylinder is executed under the environment of ANSYS8.0. The low inherent frequency and vibration type of the cylinder structure are calculated which indicates that the modified cylinder can work smoothly at high speed.5. The FEM simulation of the gap impact process about both blanket in existence and cylinder filled with foamed aluminum are carried out, the vibration response of them are obtained. The simulation research indicates that the blanket cylinder filled with foamed aluminum can expedite the vibration energy damping and reduce the bended vibration.A shock absorption scheme about printing cylinder is concluded in this paper based on practice, which are both important to improve the design capability of homemade press and minish quality gap between homemade press and foreign advanced one.