Geodesic-based iso-scallop tool path planning for complex free-form surfaces with uncut region elimination

Complex free-form surface machining plays a critical role in biomedical and customized manufacturing, where high manufacturing accuracy is essential for ensuring functional and anatomical performance. Traditional iso-scallop tool path planning methods control scallop height to enhance surface quality. However, these methods often struggle to balance machining efficiency and precision, resulting in redundant tool paths or uncut regions, particularly when applied to triangular mesh models.To address these limitations, this study introduces a geodesic-based framework that constructs curvature-adaptive contours as tool paths using the heat flow method. A novel strategy based on direction field singularities and a Minimal Envelope Line is developed to accurately detect uncut regions, which are subsequently resolved through globally optimized Clean-Paths.Experimental results on synthetic and anatomical surfaces confirm the effectiveness of the method in minimizing redundant paths, eliminating residual uncut regions, and maintaining scallop height within prescribed tolerances. The approach also demonstrates reduced overall tool path length and computational time compared to benchmark methods, validating both its precision and efficiency. By integrating geodesic-based tool path planning, critical points informed uncut detection, and global Clean-Path optimization, this work presents a geometry-aware strategy for iso-scallop machining of complex mesh surfaces, offering improved scalability, accuracy, and reliability in mesh-based CNC applications.