High speed machining is usually associated with any spindle speed above 15k rpm, but it is much more than just a faster spindle. The whole machine must be considered when selecting a good candidate machine for HSM. Thermal compensation, overall machine rigidity and construction, positional feedback, the motion control system, tool retention, and many other characteristics must be looked at, in detail, before determining that a particular machine is suitable for the task.
Traditionally, finish machining of hardened materials was performed by the use of EDM technology; and although this process was very effective, shops were continuously looking for faster and more efficient ways to produce their products. Eventually, as CAD/CAM software technology evolved, and new and more productive toolpath generation became available, the use of these advanced CAM systems also began to grow. Although the use of this new technology was primarily focused on the die mold industry in the beginning, it has become much more prevalent today - and is present in all areas of the manufacturing arena. Subsequently, and in addition to efficiently removing large amounts of material very quickly, the technology has proven to be quite effective for machining thin walled features as well.