Metal injection molding MIM stainless steel product accessories

Product Details

The development of stainless steel metal injection molding MIM technology has played an important role. For this reason, the MIM technology process parameters and the development of stainless steel are being studied. All steps of the method were studied, including the influence of binder composition and rheological parameters. Of particular interest is the role of surface additives and other adhesive components and the rheology of raw materials studied in these works. Most of the research is carried out in the most commonly used powders, but there are also works involving phase change hardening steels and special processes such as MIM powders. It is another important technical parameter that affects rheological properties.

MIM technology originated in some European countries and was first used in the development and application of military equipment components. In recent years, through the introduction of MIM technology in the Yangtze River Delta region in China, with continuous exploration and practice, it has been successfully applied to many popular fields such as auto parts, 3C digital products, medical equipment, tool locks and so on.

01

Overview

Metal Powder Injection Molding Technology (MIM) is a new type of powder metallurgy near-net forming technology formed by introducing modern plastic injection molding technology into the field of powder metallurgy. It is a forming method in which a plasticized mixture of metal powder and its binder is injected into a mold.

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02

Process flow

The MIM manufacturing process generally includes: mixing and pelletizing, injection molding, degreasing, sintering, and secondary treatment. Combining the flexibility of injection molding design with the high strength and integrity of precision metal, it is suitable for mass production of small, precise, complex shapes and metal and ceramic parts with special performance requirements. It has broad application prospects and economic value.

(1) Mixing: Fine metal powder, thermoplastic and paraffin wax binder are mixed in precise proportions. It is mixed in a special mixing equipment and heated to a certain temperature to melt the binder. In most cases, mechanical mixing is used until the metal powder particles are evenly coated with a binder and cooled to form a granular raw material.

(2) Molding: The equipment and technology of injection molding are similar to those of injection molding. The raw materials are fed into the machine to be heated and injected into the mold cavity under high pressure. This link is formed (greenpart) and demoulded after cooling. Only when the binder is melted (fully fused with the metal powder) at a temperature of about 200°C, the entire process described above can be carried out. The cavity size design should consider the shrinkage produced during the sintering process of metal parts.

(3) Degreasing: Use physical or chemical methods to remove the binder from the parts, the most commonly used is solvent extraction. Most of the binder is removed before sintering, and the remaining part can support the component to enter the sintering furnace and be volatilized during sintering. The parts change from the mixture of metal powder and binder to pure metal parts, the volume shrinks, and the shape and structure remain unchanged.

(4) Sintering: The parts are put into a furnace controlled by high temperature and high pressure. The part is slowly heated under the protection of gas to remove the remaining adhesive. After that, the part is heated to a very high temperature, and the voids between the particles disappear due to the fusion of the particles. The part shrinks directionally to its design size and transforms into a dense solid. The volume shrinks further and the shape and structure remain unchanged.