Articles & Columns

The presence of an eta phase between a coating and the substrate is generally considered harmful to coating adhesion. However, this article argues that when the formation of the eta phase is carefully controlled, it can actually enhance adhesion. The conditions that promote the formation of beneficial eta phase are explained.

The benefits of TiN and TiCN coatings are list in high-temperature applications such as the machining of exotic metals. TiAlN coatings, on the other hand, perform better at higher temperatures. This article describes the properties of TiAlN that make it the coating to use with high-temperature work. The article also reviews specific applications where shops have used TiAlN to increase tool life and productivity.

Drilling with a single- or double-tube system might be the most efficient way to drill deep holes in some applications. This article, which describes the tools and the process, says tubular drilling can pay for itself in higher productivity, thriftier manufacturing and tighter tolerances.

Several factors influence the effectiveness of a drilling operation. This article looks at a number of them, including coolant delivery, speeds and feeds, and tool selection.

Researchers studying the performance of diamond coatings have found a number of factors of the coating process that determine the ultimate success of the coating. This article looks at factors such as substrate preparation, stresses in the coating and substrate and the diamond coating's formation patterns.

When digital calipers that did not have to be zeroed before each measurement were introduced, they represented a significant advancement in electronic gaging. This article explains the technology behind these absolute-reading instruments and how they are used to make typical shop-floor measurements.

This article warns against the dangers in recent manufacturing supply trends. According to the author, both outsourcing and integrated-supply programs can have seriously detrimental effects on productivity and innovation. In this article, he explains the reasoning behind his views.

For applications that call for heavy stock removal and large areas of contact between the part and wheel, shops mount segmented grinding wheels in their vertical-spindle surface grinders. This article discusses the difference between grinding with segmented abrasives and grinding with standard wheels. Among the topics it covers are abrasive selection and performance testing.

This article reviews the causes of skin irritation suffered by some shop workers, with special attention paid to skin conditions that result from poorly maintained metalcutting fluids. The article also discusses the factors that can aggravate skin problems and suggests ways that workers can protect themselves from skin irritants.

This article traces the changes in countersink design and materials that have been made to satisfy the demands of the aerospace industry. The advantages and disadvantages of different types of modern countersinks are discussed.

This article guides the reader through the many decisions that must be made when selecting and installing a hydraulic workholding system. Basic hydraulic system design principles and maintenance also are discussed.

Although machinists are using cermet and ceramic cutting tools for an increasing number of applications, they have been slow to adopt them for boring. This is beginning to change, however. This article describes some of the ways a boring operation can benefit from the use of these tools.

When shouldered parts are held for turning with a draw-in collet, length-control problems can result. This article provides directions for making collet add-ons that allow the machinist to locate the part against the spindle face, providing a consistent length from part to part.

By recycling used metalworking fluids, shops can realize considerable savings in fluid and disposal costs. This guide takes the reader through the fundamentals of fluid recycling and management. Excerpted from a manual on the subject, the piece covers both the care and cleaning of fluids and fluid-handling equipment.

Traditional tap/drill charts recommend drill diameters for each size of tapped hole. But, according to this article, these recommendations are based on the size holes that were typically produced by less-accurate tools and processes used in the past. This article suggests guidelines for producing holes that will, in turn, produce correctly sized tapped holes.

Amorphous diamond coatings can offer performance close to that of CVD diamond film at a fraction of the cost. This article describes the amorphous diamond coating process and the coating that is produced. A comparison to CVD diamond coatings is also presented.

This article makes the argument that ball-drive quick-change tapholders, which transfer torque through hardened-steel balls fitted into mating detents, are more reliable than tang-drive units. The technology behind ball-drive tapholders and the design's benefits are explained.

Many end users would like to see carbide tool standards that would ensure consistent quality in tools from shipment to shipment or between manufacturers. Today's C and ISO designations do not provide this assurance, according to this article. The article looks at the problems that arise because of a lack of standards and the attempts being made to guarantee consistent quality in the shop.

The more sophisticated die-sinker EDMs on the market today possess enough intelligence to monitor cutting conditions and make necessary adjustments on the fly. This article describes the technology that drives these smart machines and the "fuzzy logic" they use to maintain an optimal spark.

Modern control technology makes extremely fast milling speeds possible. But the top speed can only be as fast as the slowest link in the chain between controller and machine. This article looks at some of the bottlenecks that can prevent a mill from running at full speed.