Machining of powder metallurgy parts

The product structure of powder metallurgy materials can be divided into the powder metallurgy machine parts and ferrite magnetic material. They include eternal life magnet magnetic materials, soft magnet magnetic materials; carbide materials and products, high melting point metal materials, refractory metal materials and fine ceramic materials or products.

The powder metallurgy process has many important and unique advantages, such as net shape to eliminate the cutting, as well as the use of parts manufactured by powder metallurgy process, in part consciously leaving the remnants of long-short structure, improve the parts self-lubricating and noise effects In addition to using the manganese powder metallurgy manufacturing process capable of producing complex alloy parts with the traditional casting process difficult or impossible to manufacture. The original intention of using powder metallurgy manufacturing process is to eliminate all the processing, but this goal has not yet reached. Most part only close to the final shape, but also need some finishing. However, compared to castings and forgings, powder metallurgy parts is durable, it is difficult to process, which also restricted the promotion and application of powder metallurgy manufacturing process.

Hole rate reduces the workability of powder metallurgy parts. Because the tool would be subjected to damage of the porous structure, porous structure is one of the characteristics of the powder metallurgy parts widely used. The porous structure is widely used in one of the characteristics of the boron powder metallurgy parts. The porous structure of the reservoir and noise, but also produce micro intermittent cutting. When the impact to the solid particles move back and forth from hole to tip. This can lead to small rupture deformation and small chip along the cutting edge.

Difficulty processing the powder metallurgy industry in the continuous development of one of the goals is to eliminate machining, and a major attraction of the powder metallurgy process is only a small amount of processing, but many parts still need to deal with the accuracy or better surface finish. Unfortunately, the processing of these parts difficult. Met the majority of the trouble is caused by the porosity. To overcome these problems, several unique technologies. The porous surface structure can often be closed by infiltration. Usually requires additional free cutting. Recently, has been designed to increase the cleanliness and reduce oxides and carbides in the heat treatment to improve the powder production technology.

Completing porous structure of closed surface is by metal or polymer infiltration. Experiments show that infiltration of real bit is to close the surface of the porous structure, thereby reducing the cutting edge micro-fatigue. The most widely used tool in the processing of powder metallurgy parts is wear a good surface roughness conditions, resistance to edge cracking and BUE material. These features are useful for any machining operation is particularly important in the processing of powder metallurgy parts. These tool materials including cubic boron nitride cutting tools, coatings and coating metal ceramics as well as improved coating sintered carbide.

When hardness of powder metallurgy parts are lower than rockwell 35 degrees and the bronze powder (FCu 663) particle itself’s hardness does not exceed the scope, the cermet is usually selected. Cermet is hard and can effective organize BUE and can withstand high speed. In addition, because the metal-ceramic has always been used for high-speed steel and stainless steel processing finishing, they usually have suitable close to the ideal geometric groove of molded part. The cermet is most commonly used for turning and boring operations. Source:http://www.mhcmp.com