Optimization of dry compression molding process parameters for magnetic abrasive grains based on discrete element method

Abstract

In order to explore the influence of various process parameters in the pressing stage of magnetic abrasive grain bodies on their forming quality, optimize the sintering preparation parameters of magnetic abrasive grains, and prepare high-quality magnetic abrasive grains, the dispersion element model of dry pressing forming of magnetic abrasive grains was established with iron-based alumina magnetic abrasive grains as the research object. By changing the pressing force, pressing mode, friction coefficient, die height-diameter ratio and other process parameters, the influence of each process parameter on the forming quality of the magnetic abrasive grain bodies was explored, and the optimization of process parameters in the pressing process was realized. The results show that the larger the pressing force, the smaller the porosity of the green body. However, if the pressing force is too large, cracks will appear on the outer surface of the green body, affecting the integrity of the surface morphology of the green body. Therefore, a pressing force of 75 to 125 MPa should be selected. The density of the green body obtained by two-way pressing is more uniform, and the mechanical properties are better. The higher the height-diameter ratio of the mold, the higher the porosity of the green body, and the smaller the axial stress of the green body. The smaller the friction coefficient between particles and between the side wall and particles, the smaller the porosity, the better the density and the better the homogeneity of the green body. When adding an appropriate amount of lubricant in the mixing stage of the magnetic abrasive particles, the friction coefficient between the magnetic abrasive particles and between the particles and the side wall of the mold can be appropriately reduced, thereby improving the quality of the abrasive body.

Keywords

• magnetic abrasive
• sintering method
• porosity
• billet mass