<p>Ti-6Al-4V titanium alloy presents significant drilling challenges due to high cutting forces and rapid tool wear, necessitating advanced methods for process optimization. This study aims to systematically quantify the influence of drill bit geometric parameters on drilling forces through an integrated finite element and experimental approach. A fully parameterized 3D finite element model of the drilling process is developed, incorporating realistic tool geometry, material constitutive laws, and dynamic contact conditions. The model is rigorously validated against experimental drilling tests, demonstrating a prediction accuracy within 10% for axial force. Results indicate that among the geometric parameters, the helix angle exerts the most significant effect on reducing thrust force, followed by the point angle and the core radius, while the cutting edge margin height shows minimal impact. Furthermore, drilling force increases proportionally with feed rate and drill diameter, and exhibits a complex relationship with spindle speed due to thermal softening. This work provides a validated predictive tool and clear guidelines for the model-based design of drill geometry and the selection of machining parameters, thereby reducing reliance on empirical methods in the machining of difficult-to-cut materials.</p>