Some knowledge points of powder injection, MIM powder injection manufacturers tell you

MIM powder injection manufacturers believe that metal powder injection molding technology is a multidisciplinary product of plastic molding technology, polymer chemistry, powder metallurgy technology and metal material science. Using mold injection molding blanks to quickly and accurately materialize high-density, high-precision, three-dimensional complex-shaped structural parts into products with certain structural and functional characteristics, and directly mass-produce them, is a new revolution in the manufacturing technology industry. This technology not only has the advantages of less processes, no cutting or less cutting, and high economic benefits, but also overcomes the shortcomings of traditional powder metallurgy products such as uneven material, low mechanical properties, difficulty in thin-wall forming, and complex structure, especially suitable for small, complex, Mass production of special metal parts.

    MIM powder injection manufacturers believe that the particle size of the metal powder used in the MIM process is generally 0.5~20m; theoretically, the finer the particle, the larger the specific surface area, and the easier it is to form and sinter. The traditional powder metallurgy process uses coarse powder larger than 40mm. The function of the organic binder is to bind the metal powder particles, so that the mixture has rheological properties and lubricity when heated in the barrel of the injection molding machine. The carrier that drives the powder flow. So the choice of binder is the carrier of the whole powder. Therefore, the choice of bonding and stretching is the key to the entire powder injection molding. Requirements for organic binders:

    1. Less dosage and less binder can make the mixture have better rheology;

    2. No reaction, no chemical reaction with metal powder in the process of degumming;

    3. Easy to remove, no carbon residue in the product.

    MIM powder injection manufacturers believe that mixing is to uniformly mix metal powder and organic binder together to make various raw materials into an injection molding mixture. The homogeneity of the mixture directly affects its flowability, which in turn affects the injection molding process parameters and even properties such as the density of the final material. The process of injection molding is the same as that of plastic injection molding, and the equipment conditions are basically the same. In the process of injection molding, the mixture is heated in the barrel of an injection machine into a plastic material with rheological properties, which is then injected at the appropriate injection pressure to form a billet in the mold. Microscopically, the injection molding body should be uniform, so that the product can shrink uniformly during sintering.

    MIM powder injection manufacturers believe that the organic binder contained in the green body must be removed before sintering. This process is called extraction. The extraction process must ensure that the binder is gradually discharged from different parts of the billet along the tiny channels between the grains without reducing the strength of the billet. The removal rate of the adhesive generally follows a diffusion equation. Sintering can shrink and densify the porous degreasing body into a product with certain structure and properties. Although the performance of the product is related to many process factors before sintering, in many cases, the sintering process has a great or even decisive influence on the metallographic structure and properties of the product.