FEA Based Optimization of Blank Dimension for Hirth Coupling Gear Semi-Open Die Forging Process

This study aims to optimize the semi-open-die forging process of Hirth coupling gears by analyzing the influence of initial material dimensions. Due to the gear’s complex radial tooth geometry, challenges such as material overflow, surface irregularities, and localized deformation hinder dimensional accuracy. A parametric study was conducted on the initial inner diameter of the workpiece, with die geometry held constant. Evaluation criteria included flash volume, reaction force, and geometric profile deviations based on ISO 1101 tolerance standards. Results show that selecting an optimal inner diameter minimizes flash volume while preserving profile accuracy. Under optimized conditions, the final geometry exhibited a maximum deviation within 0.05 mm, meeting industrial tolerance requirements. These findings offer practical guidance for forging precision components, contributing to reduced material waste and improved process efficiency.