Research On Mechanism And Optimization Control Of Powder Pressing Process

The powder pressing process is widely used in the metallurgical and ceramic industries,but the research is not deep enough.The pressing process of the powder mainly includes: a stirring cloth process and a press forming process.This topic mainly studies the process of powder mixing and the process of press forming,establishes the model of mixing fabric and pressing process,and optimizes the control by simulation and experiment to solve the problem of uneven distribution during the process of powder mixing and the pressing process.At present,there are few researches on vertical two-axis agitators,especially the fourcavity agitating and distributing system,and no related process model has been established.In this paper,the factors and laws affecting the difference of the maximum weight of each cavity in the four-cavity stirring fabric system are studied.The applicability of discrete element software and similarity principle in the simulation of the system is analyzed.Through the mechanical analysis and EDEM simulation,the influence of blade geometric parameters and motion parameters on the range of powder action was studied,and the mixing fabric process model was established.The orthogonal test and the empty column test were used to test whether the stirring system had systematic error.The agitator was optimized by the mixing process model.The design comparison experiment verified the optimization effect.The design experiment studied the primary and secondary factors affecting the difference between the maximum weight of the four-cavity,and found a set of optimal parameters to improve the uniformity of the four-cavity fabric.In the study of powder compaction,most of the focus is on the pressing of metal particles,the research on the suppression of ceramic powder is rare,and the problem of exhaust in the pressing process is hardly considered.In this paper,the relationship between the compressive capacity of ceramic powder and the pressing force under different pressing forces was studied experimentally.Three stages in the process of pressing ceramic powder were obtained.Combined with the compression process of powder,the mechanism of pressing process at each stage was analyzed.The stratification mechanism of the edge and intermediate bricks was studied,and the gas path law and the position and shape of the gas accumulation area were obtained.The force analysis of the whole body of the compact and the center of the upper surface was carried out,and the control parameters affecting the stratification of the blank were found.The critical state equation of the stratification of the brick during the pressing process was established,and the reason for the stratification of the blank was analyzed.A measure to reduce the stratification of the green body is proposed for the ceramic powder particles and the pressing process.Finally,the primary and secondary factors affecting the stratification of the green body during the powder compaction process were analyzed by orthogonal experiment,and the pressing process was optimized.