Aluminum Alloys.
High-speed machining dynamics, galling prevention, and operational specifications.
6061-T6 & 7075-T6 Dynamics
Aluminum requires entirely different geometry and strategies than steel. Because of its low melting point and high ductility, the primary failure mode is not abrasive wear, but Built-Up Edge (BUE) / galling, where the aluminum pressure-welds itself to the carbide flutes, instantly destroying the tool.
Tool Geometry
Endmills for aluminum utilize 2 or 3 flutes (rather than 4-6) to maximize the gullet space for chip evacuation. The rake angle is highly positive to shear the material rather than push it. Most critically, they are polished or coated with ZrN/TiB2; standard AlTiN coatings used for steel contain aluminum and have an affinity for the workpiece, drastically increasing BUE.
Speeds & Feeds Paradigm
Aluminum is frequently machined at the absolute maximum RPM limit of the spindle. Surface footage (SFM) can safely exceed 3,000 to 5,000 for high-end carbide. The limiting factor is usually the machine's axis acceleration capabilities (G-force limits) when attempting to execute tight toolpaths at 500+ IPM.