Machining

This article compares hard turning to grinding for finishing hardened steel parts and discusses which operation would be more appropriate for various situations. The article also looks at the machine tool, insert and cutting parameters required during hard turning.

According to this article, the short-bar barfeeders that are on the market today are not plagued by the drawbacks that have become associated with barfeeding. The units load 5-foot bar stock into a lathe rather than the longer stock loaded by earlier units.

Honing was originally a surface finishing operation that did not remove significant amounts of material. This article discusses brush honing, a process the authors say produces results similar to what honing was originally intended to produce. Proper boring is also discussed, because, according to the authors, a properly bored hole will not require further correction through modern aggressive stone honing techniques.

The efficiency of a die-sinker EDM operation can be enhanced by automating at least part of the work handling or tool handling. This article describes the automation that is available, from the simplest electrode grippers to fully automated toolchanging systems.

Copper can be difficult to EDM because its thermal conductivity changes electrode wear and process behavior. This guide covers the settings and strategy shops should review first.

For drilling standard holes in metal, there are three primary types of drills: twist, spade and indexable insert. This article discusses the pros and cons of each design and the applications for which each might be appropriate. Factors considered include hole depth, tool cost, drill speed, coolant delivery, tool inventory required, machine tool requirements and expected tool life.

When hole depths exceed four times the drill diameter, problems with cooling and chip evacuation can arise. This article discusses these problems and the drill geometries, machining parameters and coolant options that can minimize them. Charts are included giving speeds and feeds for various workpieces and drill diameters.

Guide bushings are used in difficult holemaking applications to ensure that the drill produces round straight holes. This article discusses the types of bushings commonly used and the materials they are made from. Guidelines for sizing bushings for a given operation are also supplied.