Key Features of the Required CNC Machine:

5-Axis Simultaneous Control: Allows the cutting tool to approach the complex blade surfaces from the optimal angle, maintaining cutting efficiency and surface finish.

High Speed Spindle (HSM): Often 15,000 - 30,000+ RPM. Essential for machining aluminum and other non-ferrous impellers common in aerospace and racing. For titanium or stainless steel, high torque is also critical.

Precision and Rigidity: To hold tight tolerances on blade profiles, hub contours, and balancing requirements.

Advanced CNC Controller: To smoothly process complex toolpaths and handle trochoidal milling strategies for tough materials.

Key Considerations for CNC Machining an Impeller:

• Workholding: Specialized fixtures or mandrels that clamp from the central bore, leaving all blades exposed. Hydraulic or thermal expansion chucks are common for precision.

• Tooling: Long-reach, tapered neck ball-nose end mills are essential to reach deep into the blade passages without shank rub. Tool deflection is a major concern.

• Material:

  • Aluminum 7075, 6061: Most common for aerospace, HVAC, turbochargers. High-speed machining is used.

  • Stainless Steel (17-4PH, 316): For pumps handling corrosive fluids.

  • Titanium (Ti-6Al-4V): For high-performance aerospace and marine applications. Requires very specific parameters.

  • Inconel: For extreme temperature applications (e.g., turbine engines). Very difficult to machine.

• CAD/CAM Software: Specialized modules for impeller machining (e.g., in Siemens NX, Mastercam, or dedicated software like OpenMind's hyperMILL) are used to generate collision-free, efficient toolpaths.