What is Metal Powder Injection Molding ?

metal powder products

A revolutionary powder metallurgy near-net molding technique called MIM brings contemporary plastic injection molding technology to the field of powder metallurgy.

Powder injection molding process: The final product is produced by sintering densification after the solid powder and the organic binder have first been thoroughly mixed and then granulated before being injected into the mold cavity by an injection molding machine in a heated plasticized state (around 150°C). Powder metal parts provide superior performance, consistent organization, high precision, and reduced manufacturing costs when compared to parts made using the traditional method. The usage of powder metal components is widespread in the disciplines of electronic information engineering, biological medical equipment, office equipment, automobiles, machinery, hardware, sporting goods, the watch industry, armaments, and aerospace, among other industrial fields. Therefore, it is generally accepted that the advancement of this technology will bring about a revolution in the fields of parts forming and processing, sometimes referred to as “today’s most popular parts forming technology” and “21st-century forming technology.”

 

Powder Injection Molding process

 

powder injection molding process

MIM powder

In general, the metal powder used in the MIM process has a particle size range of 0.5 to 20 microns. Theoretically, the smaller the particle, the easier it is to form and sinter because the higher the specific surface area. Powder that is more coarse—greater than 40 m—is used in the conventional powder metallurgy process.

 

Organic adhesive

The role of organic adhesive is to bond metal powder particles, so that the mixture has rheological properties and lubricity when heated in the injection machine barrel, that is to say, the carrier that drives the powder flow. Therefore, the choice of adhesive is the carrier of the whole powder. Therefore, the adhesion selection is the key to the entire metal powder injection molding. Requirements for organic adhesives: 1. Less dosage, less adhesive can make the mixture produce better rheology; 2. No reaction, no chemical reaction with metal powder in the process of removing the adhesive; 3. Easy to remove, no residual carbon in the product.

 

Mixing

To create mixes for injection molding, different raw materials are uniformly combined with an organic binder and metal powder. The finished material’s density and other characteristics, as well as its fluidity and other process parameters, are all directly influenced by the mixture’s homogeneity. molding by injection The basic equipment requirements for this step method and the plastic injection molding process are the same. In the process of injection molding, the mixture is heated in the barrel of the injection machine to make a rheological plastic substance that is then injected into the mold at the proper injection pressure to create a blank. The microstructure of the injection molded blank should be uniform, so that the metal powder products can shrink evenly during the sintering process.

 

Extraction

Before sintering, the organic binder present in the blank must be removed, a procedure known as extraction. The adhesive must be progressively released from various areas of the blank along the microscopic channels between the particles throughout the extraction process to avoid weakening the blank. In most cases, the exclusion rate of a binder follows the diffusion equation. The porous, degreased blank can shrink during sintering and densify into a product with specific structure and qualities. Although many process variables exist before sintering that affect the product’s attributes, sintering often has a significant, even deciding, impact on the metallographic structure and characteristics of the finished product.

 

 

The particle size of the raw material powder used in MIM powder is 2-15μm, while the original powder particle size of traditional powder metallurgy is mostly 50-100μm. The high density of the finished product in the MIM process is due to the use of fine powders. MIM process has the advantages of the traditional powder metallurgy process, but the high degree of freedom in shape is not achieved by traditional powder metallurgy. Traditional powder metallurgy is limited to the strength and filling density of the mold, and the shape is mostly two-dimensional cylindrical.

 

Expectations from manufacturers are at an all-time high. Better strength and density, more robust metal products, and goods made of special materials specifically for them are what our consumers want. How can businesses stay up with Metal Powder Injection Molding (MIM)? How can we overcome the constrained design freedom that manufacturers have previously experienced? It all boils down to the raw materials, which are the process’s cornerstone. JH MIM wants to provide customized components that adhere to the highest requirements by using the optimal combination of materials.

Tags  Metal Injection Molding   |  MIM Materials  |  Design

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