| At present, high speed, high efficiency, high performance and high accuracy have already become the most important developing trend of the modern offset printing machine. Printing Cylinder is the key part of the press and its performance influences the quality of products directly. In the course of printing, the cylinder bends in the length direction. It is not even along the distribution on the axial of the cylinder, both ends of the cylinder impression strength are great, and middle position impression strength is small. In order to improve the disparity of impression strength, we must improve the bending rigidity of the cylinder itself, reduce its bending in the course of printing. Meanwhile, working performance of the cylinder and its dynamic performance are closely related. So carry on the dynamic characteristic analyze to the cylinder, combine with the structure design and improvement of the cylinder can improve the products, and have very important actual meanings to improve the quality of printed matter.This dissertation is based on finite element method theory and structural finite element dynamical analysis, investigates the impressing cylinder of J2108 offset printer, and uses ANSYS8.0 finite element analyzing software developed by American ANSYS company to build finite element model of impressing cylinder and then do the static analysis to it, gets the bending situation of impressing cylinder during printing. According to the analyzing result, optimizing the structure of impressing cylinder to increase the bending rigidity of the cylinder, reduce the bend out of shape and improve printing quality. Then carries through numerical simulating analysis by Lanczos mode analyzing method, gets the former ten natural frequencies and modes in order to examine whether the dynamic performance of the impression cylinder has been improved.After improving, bending of impression cylinder is reduced in the course of printing, the largest deflection has reduced by 2.581μm , has improved its staticperformance. At the same time the first natural frequency is increased by 2.45%, the second natural frequency is increased by 3.33%. The dynamic performance of impressing cylinder on J2108 press is greatly improved. |
