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The Complete Classification of Cutting Tools in CNC Machining

Fiona Huang&CNC Professor

Fiona Huang&CNC Professor

Formerly a professor of CNC technology at a university, now working at Yumei Hardware as a senior executive, with extensive expertise in advanced intelligent CNC machining.

Update Time: August 9, 2025

Cutting tools can be categorized into five types based on workpiece surface machining requirements:

External Surface Tools: Turning tools, planing tools, milling cutters, external broaches, and files.

Hole-Making Tools: Drills, reamers, boring bars, internal broaches, and taps.

Threading Tools: Taps, dies, thread mills, thread turning tools, and thread cutting heads.

Gear Cutting Tools: Hobs, shaper cutters, shaving cutters, and bevel gear cutters.

Cutting-Off Tools: Circular saw blades, band saws, hacksaws, parting tools, and slitting saws.

Additionally, there are modular tooling systems for combined operations.


Classification by Cutting Motion & Edge Geometry

  1. General-Purpose Tools
  • Examples: Turning tools, planing tools, milling cutters (excluding form tools), drills, reamers, and saws.
  • Features: Versatile but require manual adjustments for complex profiles.
  1. Form Tools
  • Examples: Form turning tools, form milling cutters, broaches, and taper reamers.
  • Features: Cutting edges mirror the workpiece contour for precision shaping.
  1. Generating Tools
  • Examples: Gear hobs, shaper cutters, and bevel gear planers.
  • Features: Create complex geometries (e.g., gear teeth) via synchronized motion.

Tool Structure

Every tool consists of:

  • Mounting Section: Integrates with machine spindles (via tapered shanks, cylindrical shanks, or flanges).
  • Working Section: Includes cutting edges, chip-breakers, coolant channels, and calibration zones.

Construction Methods:

  • Solid Tools: Single-material design (e.g., HSS drills).
  • Brazed Tools: Carbide tips fused to steel bodies.
  • Mechanically Clamped Tools: Indexable inserts or brazed tips secured via screws/clamps.

Cutting Geometry & Performance

Key angles (rake, relief, cutting edge) significantly influence:

  • Chip Control: Higher rake angles reduce heat but weaken edges.
  • Surface Finish: Precision-ground edges minimize post-machining work.
    Optimization depends on workpiece material, tool substrate, and operation (roughing/finishing).

Tool Materials

MaterialBest ForLimitations
HSSGeneral-purpose machiningLimited heat resistance
CarbideHigh-speed operationsBrittle
CermetFinishing hardened steelsLow toughness
CeramicsHigh-temp alloysChipping risk
PCBN/PCDUltra-hard materials (HRC>50)Cost-prohibitive

Coating Tech:

  • CVD/PVD Coatings (TiN, Al₂O₃, TiCN) extend tool life 1–3× by reducing wear.
  • Nano-coatings enhance heat dissipation for dry machining.

Industry Trends

  1. Material Innovations:
  • Ultrafine-grain carbides and nano-layered coatings dominate.
  • PCD/PCBN adoption grows for aerospace composites.
  1. Smart Tooling:
  • Sensor-equipped tools for real-time wear monitoring.
  • AI-driven presetting systems minimize setup errors.
  1. Sustainable Machining:
  • Dry-cutting and minimum-lubrication tools reduce waste.

“The future lies in tools that marry hardness with toughness—like diamond-coated carbides for titanium.”IMN Tech Report


Pro Tip: For aluminum, use PCD-tipped end mills; for Inconel, opt for ceramic-insert drills. Always match coating to workpiece chemistry!

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