Study On Reliability Of Kinematic Accuracy For Multi-link Mechanism Of High-speed Precision Press

With the deep research on high-speed precision press by the scholars of domestic university and researchers of enterprise,the gap on velocity and accuracy of high-speed precision press in China is becoming smaller with the advanced overseas enterprises and some accepts have reached the international advanced level.However,because of the insufficiencies of understanding of the reliability technology and the deficiency of the research team on related technology,the medium and high quality press for domestic lack competitive ability.Multi-link mechanism posseses the characteristics of long transmission route and many parts,so that the original errors caused by manufacturing error,elastic deformation and joint clearance are more likely to reduce the reliability of kinematic accuracy.This paper presents a method for the analysis and prediction on the dynamic accuracy of down dead point by analysing the instantaneous reliability of kinematic accuracy.In order to verify the feasibility of this method,the dynamic accuracy of down dead point for JF75G-300 high-speed press is tested.The reliability of kinematic accuracy for a multi-link high-speed precision which is developing is also predicted.The major contents of this paper include:1.Kinematic equations for the drive mechanism of a multi-link high-speed precision press were established and derived first,and the curves of displacement,velocity and acceleration for slider is also plotted based on MATLAB software environment.The effect of the bar length variation of slider's displacement,velocity,acceleration is also analyzed based on the parametric model which is established with ADAMS.The performance of the press was considered as Multi-objective Programming to be optimized and a group of ideal parameters can be got.2.D'Alembert's principle is used to build the kineto-statics equation of the mechanism,and then the dynamic simulation was operated by ADAMS view.The 3D model of the drive mechanism also been made based on the need for structure and the design experience by using Solidworks.3.The theoretical calculation model about the reliability of kinematic accuracy for the mechanism and the Monte Carlo simulations was introduced.The influencing factors on the reliability of kinematic accuracy also been analyzed.Taking JF75G-300 which is developed by Xuzhou metal forming machine group for example,the time reliability of its kinematic accuracy is analyzed.The effect of speed variation for high-speed press kinematic accuracy reliability is verified through measuring dynamic accuracy of down dead point in different speed of JF75G-300 high-speed press.4.Taking the manufacturing error,elastic deformation and the joint clearance in different speed circumstances into consideration,the kinematic accuracy reliability of the multi-link drive mechanism is analyzed on the basis of the Monte Carlo simulation method.This analysis method of the kinematic accuracy can provide a theoretical basis for the optimization of the machining accuracy,component's stiffness and the assembly accuracy.