Dynamic Modeling And Optimization Of The Cam Mechanisms In Delivery System Of An Offset Press

Sheet-fed offset press, an automatic high-speed operation of the machinery, is widely used in printing industry.The delivery unit in the new product has a great incentive in the work. Supported by the Jiangsu special fund project for scientific and technological achievements, the cam mechanism and torsion-bar-spring gripper within delivery unit were analyzed. Through taking a better combination of parameters, the delivery unit was made to match client usage needs. This paper has mainly completed the following aspects of work.(1) Virtual prototype with rigid-flexible delivery unit has been modeled and simulated. The three-dimensional model of delivery unit was built. A torsion-bar-spring gripper model was established based on rigid flexible coupling technology. Paper receiving chain model was simplified. According to the practical constraint and motion mode, the virtual prototype was established.(2) Cam optimization based on virtual prototype. The motion law of cam follower was derived, and the cam multi-objective optimization mathematical model was established. Cam optimization schemes were proposed. By means of the reverse method, the actual profile of the cam was obtained. By comparing within the virtual prototype, the optimization effect of the cam was reflected.(3) Cam optimization based on dynamic model. First of all, by establishing a SDOF model of cam follower, the residual vibration after the closure of the gripper was analyzed. Secondly, a 2-DOF dynamic model was established, which parameters are piecewise function. Subsequently, by using of SIMULINK, the optimization platform was set up. Cam profile was obtained by means of vector method. The input of the system is the weight of multi-objective function, the output of the system are delivery unit characteristic responses, such as cam contour curve, motion law of follower, cam kinematic characteristics, dynamic characteristics, biting force, roller force etc. Compared with the virtual prototype simulation, the correctness of the optimization platform was verified.(4) Optimization and modal testing of torsion-bar-spring gripper. The reasonable range of the stiffness and tightening angle of the torsion bar spring was proposed.Through the modal experiment of gripper, natural frequency and formation of gripper was obtained. By comparing the simulation results with the test results, the correctness of the flexible model was verified.