In the previous articles, we introduced several metal parts manufacturing processes. In this post, we are going to talk about the Powder Metallurgy & MIM(Metal Injection Molding) processes.
6.1.1 Definition of Powder Metallurgy
Powder metallurgy is a process technology for producing metal materials, composite materials, and various products by using metal powder (or a mixture of metal powder and non-metal powder) as raw materials, forming and sintering them.
6.1.2 Processes of Powder Metallurgy Technology
The process of powder metallurgy includes the following steps:
raw material mixing → forming → sintering → vibratory grinding → secondary machining → heat treatment → surface treatment → inspection → finished product
6.1.3 Advantages of Powder Metallurgy
- Most refractory metals and their compounds, pseudo alloys, and porous materials can only be produced by the powder metallurgy method.
- It saves metal and reduces product costs.
- It does not pollute the material and can produce high-purity materials.
- Powder metallurgy can ensure the accuracy and uniformity of material composition ratio.
- Powder metallurgy is suitable for producing products with the same shape and large quantities, which can significantly reduce production costs.
6.1.4 Disadvantages of Powder Metallurgy
- When there is no batch production, the decision to use powder metallurgy technology should consider the size of the produced parts.
- The cost of the mold is relatively higher compared to the price of a casting mold.
6.1.5 Application of Powder Metallurgy Processes
Powder metallurgy technology can directly produce porous, semi-dense, or fully dense materials and products, such as oil-impregnated bearings, gears, camshafts, guide rods, cutting tools, etc.
6.2.1 Metal Injection Molding (MIM)
MIM is the abbreviation for Metal Injection Molding, a molding method that injects a plasticized mixture of metal powder and binder into a mold. First, the selected powder is mixed with a binder, and then the mixture is granulated and injected into the required shape.
6.2.2 Processes of MIM
The MIM process achieves the production of parts through four unique processing steps, including mixing, forming, de-binding, and sintering. Then, it determines whether surface treatment is required based on the product characteristics.
MIM is a versatile manufacturing process that can produce complex metal parts with high precision and accuracy. It is widely used in various industries, including medical, aerospace, automotive, and consumer electronics.
6.2.3 Characteristics of MIM
- One-time molding for production
- MIM parts have good surface quality, low scrap rate, high production efficiency, and are easy to automate.
- The requirements for mold materials are low.
- Adding adhesive is crucial to MIM technology as it enhances the powder’s fluidity and maintains the blank’s basic shape during injection molding.