The simulation test analysis is carried out from the two categories of bidirectional and unidirectional pressing. In the simulation model, the set powder filler height and pressing height remain unchanged. The modified Coulomb friction model based on the nodal stress is selected to define the deformation process.5×103kg/m3.

Comparative simulation analysis of 4V, D-shaped blade tipTherefore, the use of different pressing methods or pressing parameters can change the relative density distribution in the axis direction of the green compact, which in turn affects the dimensional deformation of the green compact after sintering. For the setting of solving equations, the modified Newton-Raphson method is adopted, and the viewpoint of large displacement, large strain, and updated Lagrange method is used.

When solving, the punch and the ejector impose displacement constraints, and the mold body imposes fixed constraints on the boundary conditions. Taking the change of the relative density value from point A to point B at the wall of the mold body to analyze the influence and trend of different pressing methods on the change of density distribution of the green compact, the results are shown in Figures 2-6. The contact type of the simulation model is fully automatic contact, the WC-Co powder is a compressible deformable contact body, the punch, ejector, and mold body are all set as rigid bodies.2, ρ is the relative density of the powder, and E0 is the elastic modulus of the powder. By aligning 12×5 cylindrical products with different pressing parameters for press forming analysis, we can understand the distribution of relative density.5 at this time; the relationship between the elastic modulus and relative density It is E=E0 (1-ρ) 3.1 Model establishment

accuracy at the tip of the series of products in production, a finite element simulation analysis was performed on the products. 2, it can be seen that when the top pressure is applied, the relative density value of the upper part of the compact is larger than that of the lower part. From the comparison between Fig. Since this pressing process belongs to the cold press forming process, the influence of temperature is not considered. It can be seen from Fig. It can be seen from Figure 4 and Figure 5 that when using unidirectional pressing, the relative density difference between the bottom and top of the compact is large, and the symmetry of the upper and lower density distribution is poor. Through the comparative test of the relative density distribution of the compact at the tip of the V and D blades, we can understand the influence of the arc and angle of the tip on the density distribution of the tip, so as to find out the major and secondary factors that affect the density distribution of the tip . Friction behavior.5 (1-ρ)2, when the powder is completely dense, the relative density is 1, and the Poisson’s ratio is at most 0. When the punch moves, the upper density is greater than the bottom; the ejector moves At this time, the lower part is denser than the top part. 6 and Fig. It can be seen from Figure blowing mould 2 that when bidirectional pressing is adopted, the relative density of the green compact is symmetrically distributed up and down, but the pressing position changes https://www.pet-mould.com/product/blow-mould/ , and the stroke ratio of the punch and the ejector is 1:2. Bidirectional pressing is divided into the movement of the upper and lower punches, the die body is stationary; the upper punch and the die body move in the same direction, and the ejector is stationary; the unidirectional pressing is divided into the movement of the upper punch or ejector; the punch and ejector The setting of the stroke ratio or the top pressure value is carried out by studying the influence of the above several pressing methods or pressing parameter changes on the relative density distribution of the green compact