Dynamic Analysis On The Transient Contact Process Of Offset Press Cylinders

Printing device is the core unit of offset press, which complete the image transferduring the printing process. Because the complexity structure and self weight ofcylinder and other effect factors, the distribution of printing pressure are nonuniformwhen the cylinders are contacting with each other which finally affect the pringtingquality. In this paper, the BR622 quarter two color sheet–fed offset press was taken asresearch object, having the aid of the finite-element analysis software named ANSYSand mechanical system dynamics automated analysis software ADAMS, theprocess of cylinder contacting was simulated. The main research achievement asfollows:(1) Mechanical system dynamics automated analysis software ADAMSwas used to stimulate the process of on-off pressure. Under different cylinderrotate speed, center distance variation curves of cylinders and angular displacementvariation curves of eccentric bushing in the stiching procedure were solved. Inaddition, under different rotate speed, piston’s lowest speed satisfying the rightstiching procedure order was obtained too. Meanwhile, pneumatic system of on-offpressure mechanism was improved, as a result, accuracy controlling of the piston’sspeed and slowly stiching were accomplished.(2) Conbining the superiority of ANSYS and ADAMS, Coupled Rigid-FlexibleDynamic Analysis was made for the printing cylinder. The axial distribution curve ofthe plate cylinder with blanket cylinder and blanket cylinder with impression cylinderwere obtained.(3) The three cylinder were made contacting finite-element analysis by utilizingANSYS. The cloud image of stress and atrain in the contacting area was gained whenthe printing pressure obtained above was uploaded to the cylinder. Simultaneously, byanalyzing the influence of blanket variant on printing quality, the elongation in thecrosswise and lengthways of prints and dot extensive magnitude was gained. Meanwhile, In model analysis for the assemble, this study demonstrates the first threefundamental resonant frequencies and mode of vibration of the plate cylinder, blanketcylinder and pression cylinder. Finally, the structure of cylinder was optimal designedwhich minished the deformation of blanket and impoved the printing quality.(4) FPD9210 pressure testing system and BK testing system are used to test thepressure of plate cylinder with blanket cylinder and pression cylinder with blanketcylinder of BR622.in addition,the vibration of the wallboard was tested too. Printingpressure and vibration performance in the real printing process was obtained. Bycomparing the reality and simulatin, The accuracy of the simulation was checked.