| With the full implementation of "Made in China 2025",high-performance multi-station cold heading machines as high-end manufacturing equipment have been rapidly developed.Compared with the mold change level of cold heading machines at home and abroad,foreign countries have formed a complete set of automatic and intelligent mold change technology,while domestic enterprises usually use manual mold change,which greatly reduces the automation degree of cold heading machine products and the efficiency of cold heading machine,restricts the rapid development of China's high-end equipment manufacturing industry.This paper designs an automatic mold changer that is compatible with DBP-206 L cold heading machine to solve a series of problems in the actual production,such as high labor intensity,high labor cost,low mold change efficiency and unstable product quality.It can improve the domestic cold heading machine change level,shorten the gap with developed countries.Firstly,analyze the change process flow of cold heading machine,summarize the functional parameters of the manipulator structure design,the selection,calculation and verification of key components are carried out,and the three-dimensional model of the manipulator is established by Solid works software.In the ANASY Workbench software,the static characteristics analysis and modal analysis of the mandrel formwork are carried out by modifying the material properties,adding constraints and boundary conditions,and obtaining the deformation map,stress cloud map and modal shape diagram corresponding to the mold base.By analyzing the deformation diagram and stress cloud diagram of the formwork under static characteristics,to verify the rigid strength condition of the formwork structure satisfies the design requirements.By analyzing the various modal shape diagram of the formwork structure,the dynamic characteristics of the formwork structure are studied.Study the influence of of various modes on the formwork structure and the die change precision of the manipulator,avoid the poor precision and poor stability caused by the structural resonance,and ensures the high mold change efficiency and mold change quality of the manipulator.Based on the ANSYS Workbench finite element software,the structural optimization of the manipulator formwork was carried out,and an optimization scheme for replacing the steel plate welded structure with a hollow square steel structure was proposed.By analyzing the relationship between the design variables and the quality of the formwork,the relationship graph of stress and strain,and the image of sensitivity of design variable to objective function,the optimal sample plan is obtained and verify the correctness of the optimization scheme.Next,the kinematics model of the Cartesian manipulator is established by the robot D-H method,and the spatial position of the gripper at the end of the manipulator and the motion relationship between the axes are established.The Lagrangian method is used to obtain dynamic equation of the manipulator,which provides a theoretical basis for the ADAMS simulation to solve the mass,moment of inertia and gravity vector in each axis direction.The SolidWorks2016 3D modeling software and ADAMS software are used for co-simulation,a graph showing the displacement,velocity,and acceleration of the end-executing cylinder and the pneumatic gripper over time during the entire mold change process,and the corresponding motion and moment diagram of each axial direction of the manipulator are obtained,the systematic analysis of the movement process of the manipulator is carried out.A number of corresponding preventive measures are proposed for the chattering phenomenon that the manipulator may have during the mold change process to ensure the smooth operation of the entire manipulator changeover.Then,the manipulator's die change action is analyzed in detail,establish the motion path equation of the die change manipulator,and determine the manipulator's trajectory planning objective function and constraints.Combining the actual working conditions of the manipulator,write the algorithm program based on the "exhaustion method".Using MATLAB simulation software,calculate the manipulator's optimal mold-changing path based on the objective function,and draw a sequence diagram of the mold change path to guide the manipulator to automatically change the mold work.Finally,by analyzing the action requirements and motion laws of the cold heading die change manipulator,the overall design requirements and system components of the manipulator control system are summarized.According to the manipulator control system work flow,the pneumatic circuit control system and PLC electrical control system are designed.The ladder diagram of each cylinder action and the wiring diagram of the PLC control system are presented,and the man-machine interface system of the mold changer is designed. |
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