General use of tool material

The most widely used tool in the P/M industry are materials that are resistant to wear and fracture and do not have a built-up edge, with good surface finish. These characteristics are useful for any machining operation, especially when working with P/M parts. Tool materials included in this category are cubic boron nitride (CBN) tools, uncoated and coated metal ceramics, and improved coating sintered carbide.

CBN tool is attractive because of its high hardness and wear resistance. This tool has been used in steel and cast iron for more than 45 of the hardness of the cast iron. However, due to the unique properties of the P/M alloy and the hardness and macro hardness of major differences, so that the CBN tool can be used for soft to the hardness of 25 P/M parts.

The key parameter is the hardness of the particles. When the hardness of the particles exceeds 50 degrees, no matter how much the hardness value is, the CBN tool is available. The obvious limitation of this tool is their lack of toughness. If it is intermittent cutting or with high hole rate words including chamfering and heavy honing, cutting edge reinforcement is needed. Light cutting with a simple cutting edge can finish honing.

There are several materials CBN is effective. The best toughness of the material is mainly composed of the overall CBN. They are extremely tough and can be used for rough machining. Their limitations are usually related to surface finish. To a large extent by the composition of the tool CBN individual particles decision. When the particles fall off from the cutting edge, they will have an effect on the surface of the workpiece. But the fine particle cutter falls off a particle then the situation is not so serious.

Commonly used CBN material with high CBN content, particle size medium. The CBN finishing blade is fine grain and CBN content is low. They are the most effective for light cutting and surface finish requirements or for a particularly hard alloy.