MIM is a new metal forming process that combines traditional powder metallurgy and modern plastic injection molding technology. After years of production practice and theoretical research by industry experts, the industry found that the smaller the particle size, the more uniform the particles, the closer to the spherical powder particles are more suitable for manufacturing feed, the feed made of such powder in the subsequent product molding process fluidity Good, is conducive to the smooth completion of the entire MIM process, and easy to debond, the debonded blank shrinks evenly and to a lesser extent during sintering.
At present, the metal powders used in the manufacture of metal feed are generally divided into two types: gas atomized powder and water atomized powder. These two powders have very different shapes and properties, and no one can get a good feed with either.
The addition of water atomized powder to the gas atomized powder can improve the shape retention ability of the injection molded parts and reduce the anisotropic shrinkage. If the natural slope angle of the mixed powder is small, it means that the interaction between the particles is small, and the anisotropic shrinkage of the manufactured parts is large after sintering. Samples with large aerosolized powder content are prone to collapse after debonding.
The use of water atomized powder can maintain the shape without compromising its mechanical properties. The irregular shape of the particles affects the sinterability of the mixed powder, and the use of a larger proportion of water atomized powder can promote densification.
In summary, the influence of the shape of the metal powder particles on the MIM process is fundamental and final. Choosing the right metal powder to make the right metal feed is essential for forming high-quality MIM products.