Kinematic Accuracy Analysis And Robust Optimization Design Of Two Point Press

As an important manufacturing equipment in national defence industry，social productionand other department, two point press has high demand for kinematic accuracy, insufficientsynchronism of two point press main transmission chain will lead to displacement differencewhich is not only harmful to the press, but also to the products’ quality. Robust optimizationhas an important position in mechanical design and influence on the products’ manufacturingcost and quality. It is significant to make robust optimization design for key mechanism oftwo point press main transmission chain. To solve the problem about the press, this papertakes a two point press as research subject. Firstly, the parameters of two point presskinematic accuracy are analyzed. Then function expressions of each parameter whichinfluences to kinematic accuracy are calculated. Lastly, the optimization design model aboutkey mechanism of two point press main transmission chain is established. The main studywork is presented as follows:(1) The current state of press and its kinematic accuracy is concluded and summarized fromthe analysis of two point press kinematic accuracy, the analysis of crank slider mechanismkinematic accuracy and the influence of mechanism with joint clearances. The researchesabout robust optimization design studied by scholars both at home and abroad aresummarized. At last, the main contents, general structure scheme and innovation points of thisdissertation are given.(2) The types of press, operating principle of two point press and its key mechanism ofmain transmission chain are introduced. Two indicators of the press kinematic accuracy arepresented: one is verticality of press head, the other is travel error of the upper compressionbar. The parameters which influence verticality of press head and travel error of the uppercompression bar are analyzed. The sensitivity of verticality of press head and travel error ofthe upper compression bar about the proposed parameters are analyzed.(3) Three kinds of random factors which influence the kinematic accuracy of two pointpress are analyzed. Effective length models are analyzed considering clearances. Synthesizingthe factors, the numerical features of press head verticality and travel error of the uppercompression bar are summarized in a movement period. The robustness of slider is analyzedand the probability density distributions of press head verticality and travel error of the uppercompression bar are concluded. The experiment of slider displacement is conducted andcompared with simulation. (4) Taking the minimum displacement difference of two transmission chains as targetwith the range of verticality of press head and deviation, the dimensions and tolerance of keymechanism of two point press main transmission chain are robustness optimized. Comparedwith the original design, the new design is improved at insufficient synchronism of two pointpress main transmission chain as well as its robustness.