Overview
Powder Metallurgy (PM), also referred to as powder metallurgy, is a manufacturing process used to form precision parts from a variety of metal powders. The process generally involves blending, sintering and peening. The process is particularly useful for creating simple objects with complex shapes, as well as parts with consistent densities. Over the last few years, PM has become increasingly popular among manufacturers for its cost efficiency, lack of warping and ability to produce parts with high dimensional tolerances and strength.
History
Powder Metallurgy has been around for centuries. In fact, the first use of PM dates back to the 5th century in China, when pieces of metal were mixed and fired to create an alloy. In the 19th century PM underwent some major advancements, and by the 1920s the first industrial PM processes were developed in Europe. The foundation of the modern PM industry was laid in the 1930s and by the 1940s, post-World War II growth saw rapid industrial and technical improvements. In recent years PM has experienced tremendous growth, and is now the economical and preferred production process for many types of precision parts.
Principle
Powder metallurgy is a process used to produce complex components from metal powders. Metal powders are blended in a controlled atmosphere to create a homogenous mixture which is then pressed into a shape. The component is then heated causing the particles to form a strong bond. After cooling, the component is then subject to further finishing operations, such as peening and/or machining.
Process
Powder Metallurgy involves several dedicated operations. In its simplest form, it consists of 4 main steps:
1. Powder Production: Metal powder is produced from various raw materials, typically in a composite state that blends particles of different sizes & characteristics. This can be achieved through methods such as sieving and atomization.
2. Blending: Depending on the desired result, the powder is blended with various additional agents that can alter or enhance the properties of the mix. This increases its workability and homogeneity.
3. Compaction: The powder mixture is then poured into a mold and compressed with a hydraulic press, creating a more uniform piece with a customized dimensional shape.
4. Sintering: The pressed powder is heated in a furnace, which causes the particles to form inter-metallurgical bonds and enhance strength.
Materials
Various metals and alloys can be used in Powder Metallurgy to create components of different shapes and sizes. Metals such as aluminum, brass, bronze, and stainless steel can be used to manufacture complex geometries without additional machining operations. Furthermore, PM parts can be stronger and lighter than their machined counterparts. This is due to the production process, which eliminates any excess material present in machined parts.
Conclusion
Powder Metallurgy is an economical and efficient way to manufacture precision parts with complicated geometries. From aerospace industries to medical devices, this process has become an integral part of the manufacturing process in many industries. The process results in products of superior quality, tight tolerances and consistent properties when compared to parts produced by traditional machining processes.
