Single-Flute Drilling Tool for Stable Chip Evacuation

The patent merges the separate flute portions into a single integrated flute structure that serves both radially inner and outer cutting inserts. This unified flute design eliminates the structural weakness of separate flutes while maintaining adequate chip transport capability for both inserts through its continuous geometry extending from the tool tip to the rear.

The patent applies local quality by varying the flute geometry along its length to accommodate different chip transport needs. The flute cross-section and helical parameters are optimized at different axial positions to handle both small chips from radially inner inserts and large chips from radially outer inserts, with the flute being more open near the tip for small chips and having adequate capacity further back for large chips.

The unified flute structure acts as an intermediary that facilitates the transport of small chips produced by the radially inner cutting insert. The flute's continuous geometry and appropriate helical parameters create effective chip flow paths that efficiently evacuate small chips from the cutting zone, preventing chip congestion and maintaining high material removal rates despite the small chip size.

The patent employs parameter changes in the flute geometry to accommodate large chips from the radially outer cutting insert. The flute helix angle, pitch, and cross-sectional dimensions are optimized to provide adequate chip capacity and smooth chip flow paths that can handle the larger chip volumes generated during high material removal rate operations, preventing chip congestion and tool damage.