Competitive pressures are constantly forcing manufacturers to machine parts more efficiently. At the same time, builders of aerospace structures are requiring stronger, lighter structures with closer tolerances. High-speed machining (HSM) can cut cycle time while also allowing manufacturers to cut finer thinner parts than ever before. Take a small chip and go as fast as you can, is the way Alan Hollatz, proposal engineer for Makino Corp defines HSM. When machining aluminum, Hollatz advises going as fast as possible in finish cuts. Like most other machine tool providers, Hollatz recommends hollow shank toolholders over CAT type at higher spindle speeds. A key enabler for HSM is the CNC controller and its ability to move the machine accurately enough at high speed. Controllers with 'look-ahead' features that control the present speed and acceleration or deceleration of the tool based on where the tool is going to go is, by all accounts, just as important as driving the spindle at high rates.