Articles & Columns

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.

The economic benefits of high-speed machining can be lost if the wrong tools are used. This article describes the types of solid-carbide drills and endmills that can ensure long-running performance. It also covers the proper handling and setup of these tools.

Researchers at Ohio State University produced contoured cuts with different ball mills to determine the best tool material and coating for the job. This article reports their findings and offers recommendations for extended tool life when milling molds and dies.

The advent of CNCs made new threadmaking technologies practical. Among these technologies are rigid tapping and thread milling. This article describes the uses, techniques and benefits of these two threadmaking methods.

There are a variety of presetters on the market. All reduce machine downtime by allowing shops to set up tools offline. This article discusses the different presetter types and the impact that these differences will have on the instrument's price and functionality.

Manufacturing customers have begun demanding that their suppliers institute quality-control processes. At the same time, they are expecting their suppliers to adopt more efficient processes so that suppliers can reduce their prices while maintaining profitability. This article discusses these pressures and how even subtier suppliers are being affected by them.

There are some tapping situations that call for a rigid tapholder and some that call for a length-compensating holder. Often the choice depends on the capabilities of the machine and the CNC driving the tap. This article discusses why a machinist might choose one type of tapholder or the other.

Internal threads can end up undersized because of the work material's properties or because of changes to the hole's dimensions caused by plating or heat-treating processes performed after tapping. This article explains H- and D-limits and how to use them to specify a tap that will produce the right size thread, regardless of any post-tapping operations.

Researchers at the Center for Grinding Research performed a series of creep-feed grinding tests to determine the causes of the heat damage and striations they observed. The tests involved grinding slots and vertical faces. This report discusses the dynamics behind these problems and suggests ways to avoid them.

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.

Standards governing grinding-wheel safety testing do not cover all superabrasive wheels. This article suggests that these standards should include them. The author explains why as he describes a typical superabrasive wheel and the dynamics of superabrasive wheel failure.

The fundamentals of wheel dressing and truing are reviewed in this article, which covers the proper maintenance of a wide variety of wheel bonds and abrasive types. The article also discusses different truing techniques and their appropriateness for different uses.

EDM cutting conditions change throughout the cutting process as the part thickness and the level of dielectric contamination fluctuates. This article describes an experimental setup that can monitor these fluctuations and adjust the EDM's settings to maintain an optimal spark.

With wire EDM, the properties of the wire will have a large impact on the performance of the operation as well as the ease of rethreading. This article discusses the properties that ensure a good spark and reliable performance even when cutting at an angle. Real-world examples are given of users who have improved their operations by changing the type of wire they were using.

Modular toolholding systems save shops money in several ways, according to this article. By making it possible to use the same tools on several machines, for example, a modular toolholding system can allow a shop to reduce its tool inventory. This article explains many other savings in addition to tool inventory reduction.

EDMing removes material at such high temperatures that the process produces metallurgical changes in the material surrounding the cut. This article discusses the various surface effects and how they can be detected and measured. It also reviews the different methods for correcting or removing the surface flaws and roughness caused by EDMing.

Indexable-insert drills offer several advantages for producing short holes. This article describes the drills' features, uses and benefits. Tips are provided to help select the optimal tool, insert and machine settings. A trouble-shooting chart is included.

Blades for contour bandsawing vary in their materials, their tooth set and selection, their width and the way they are welded. This article discusses how each of these variables contributes to the blades' ability to cut intricate shapes without seizing or wearing prematurely. Blade lubrication is also covered.

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.