Optimization of Single-Tooth Rake Angle for Enhanced Cutting Performance in High-Strength Casing Section Milling

Section milling of high-strength casings in deep and ultra-deep wells faces significant challenges, including excessive cutting forces, rapid tool wear, and inefficient chip removal. This study proposes a novel cutting performance enhancement method through systematic optimization of the single-tooth rake angle. A 3D explicit dynamic finite element model was developed to simulate orthogonal cutting of P110 casing, validated by lathe experiments with triaxial force measurements. Results demonstrate that a rake angle of γ = 0° optimally balances cutting efficiency and chip control: it minimizes tangential and radial cutting forces, generates short C-shaped chips with 93% mud-carrying efficiency, and eliminates tool jamming risks. Negative rake angles (γ ≤ -2°) produced problematic continuous or powdery chips, while positive angles increased force variability. The 0° configuration reduced specific cutting energy and enhanced tool stability, directly contributing to extended tool life and operational safety. This work provides a foundational strategy for designing next-generation section milling tools targeting high-strength wellbore applications.