Materials

The trend toward developing finer and finer carbide grains continues. The author looks at recent developments in the production of nanosized tungsten-carbide grains, which are smaller than 0.2 microns in diameter. Though not used widely at present for the production of cutting tools, some predict that will change as the technology evolves.

High-silicon aluminum--aluminum that consists of at least 11.8 percent silicon--has qualities such as lightness and strength that appeal to automakers. The abrasives nature of the material, however, makes it difficult to machine. The author offers suggestions for milling, tapping, drilling, turning and grinding high-silicon aluminum.

When shops crank up the speed, they have to be prepared for the consequences, even if they’re milling "easy-to-machine" aluminum.

The development of the CVD thick-film diamond process has made it possible to produce tools that can machine abrasive work materials without losing their cutting edge. In this article, the technology for producing the diamond film and the brazing of these thick-film chips onto inserts is described.

High-performance aluminum-alloy workpieces are prone to residual stresses that can lead to part distortion. This article reviews the milling tools and practices that affect these stresses. Some tools and practices alleviate the stress, while others allow the machinist to mill the part without adding more stress.

Cermet inserts have evolved into cutting tools capable of finish-turning steel reliably at high speeds. This article traces the developments that have led to modern cermets and describes the properties that enhance the performance of these tools. The development of coatings for cermets is also covered.

This article describes the shapes and sizes of diamond particles produced through standard manufacturing processes. The uses for these different types of particles are also explained, with an emphasis on particles used in superfinishing powders and slurries.

Improvements in cermet and ceramic inserts have made them a good choice for high-speed milling. This article describes how the compositions and designs of these newer inserts make them tough enough to withstand the punishment of a milling operation while maintaining the hardness that makes them wear-resistant.

Dry milling and turning grow in popularity day by day, but dry drilling is
another matter. Because of the nature of drilling, it's more difficult to
perform this operation without coolant. Still, progress is being made,
thanks to research and more sophisticated coatings.

Stainless steel is one of the more difficult materials to cut. This article discusses the problems that can occur when turning various types of stainless steels, the reasons for these problems and ways to avoid them. Advice is given on diagnosing problems based on tool-wear patterns. The article also suggests ways to correct problems once they are discovered.