Articles

Articles • September 1, 1996 • Joseph Halloran

Ceramics Get Tough

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.

Articles • August 1, 1996 • Martin Eastman

Quality Through the Tiers

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.

Articles • August 1, 1996 • John Edmond

The Good, the Bad and the Retapped

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.

Articles • August 1, 1996 • Allen Krenick

Rigid Rules

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.

Articles • August 1, 1996 • Peter Zierhut

New Twists on Threading

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.

Articles • August 1, 1996 • Richard McCarthy

Presetters Produce Profit

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.

Articles • June 1, 1996 • Thomas Service

Superabrasive Safety

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.

Articles • June 1, 1996 • Norman Rohr

Powder Particulars

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.

Articles • June 1, 1996 • Trevor Howes

Creep-Feed Exam

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.

Articles • June 1, 1996 • Leonard Pukaite

The Hard Truth

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.

Articles • April 1, 1996 • Lawrence Rhoades

Understanding EDMed Surfaces

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.

Articles • April 1, 1996 • K.P. Rajurkar

A Spark of Intelligence

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.