Study On Process Mechanism And Process Parameters Optimization Of Large-scale Ceramic Tile Pressing Machine

This paper focuses on the mechanism of pressing process,the process optimization of pressing process and the stability of pressing process of ceramic tile press.The ceramic tile press is studied by force analysis,numerical simulation and experimental verification.The mechanism of pressing process of ceramic tile press is analyzed and the process is optimized.The main contents of this paper are as follows:1)The compaction process and its force analysis,three common defects of brick and the assumed layered shape are introduced.Then,in order to study the gas flow characteristics in the powder compaction process,a two-fluid model is selected from three kinds of two-phase flow simulation models.Finally,three simplified models based on the two-fluid model were established respectively according to the initial,middle and late suppression periods.The characteristics of gas flow,which are often neglected in the study of powder compaction,are studied.It is found that the simulation results based on the two-fluid model are close to the actual situation of the defects in the brick,and the reason of the delamination defects in the brick is analyzed.2)A dynamic mesh based powder compaction model is established,and the most appropriate mesh size of 1mm is selected through mesh independence analysis.Then,the gasphase volume fraction distribution nephogram,gas-phase velocity vector distribution nephogram and the quality index of the powder layer are analyzed.The effects of lifting velocity target value,lifting acceleration,lifting velocity target value and pressing acceleration on the quality of powder layer and gas flow characteristics in the process of pressing are studied.Finally,the order of the factors affecting the quality of the powder layer and the optimal combination of the process parameters are obtained by orthogonal test.3)Introduced the lifting stage of powder pressing,analyzed the force of brick in the lifting stage of press head,and put forward the process optimization method of ceramic brick press based on maximum lifting acceleration.Then,the experimental platform is built,and the evaluation index of the brick quality is set according to the Leeward hardness value.Finally,the method is verified by a verification experiment,and the relationship between the experimental results and the powder compaction simulation optimization research is analyzed.The rationality of the powder layer quality index parameters and the rationality of the simulation model are verified.4)The function and force of the hydraulic cylinder in the pressing action are analyzed,and the stability of the hydraulic cylinder movement process will affect the quality of the forming brick.Then,the geometric structure of the rectangular hydraulic cylinder is introduced,and the calculation method of the index value of the cylinder motion stability is put forward.The application scope of sliding grid and moving grid is compared,and the moving grid technology is selected to apply to the model.Finally,the mesh size was selected through the mesh independence analysis,and the three-dimensional dynamic mesh model of the rectangular hydraulic cylinder was established.Through the pressure nephogram,velocity nephogram and cylinder movement stability index,the influence of the number of oil ports,the length and the diameter of the oil pipe on the cylinder movement stability is analyzed.The primary and secondary order of the factors affecting the cylinder motion stability and the optimal parameter combination scheme are obtained through orthogonal test.