<p>The micro-conical ball solid end mill as a critical tool in precision medical device machining, requires its head and neck helical grooves to be ground in a single pass to ensure the integrity of the spherical cutting edges. These cutting edges are generated by the intersection of two adjacent helical grooves. This study proposes a novel grinding wheel trajectory calculation method based on a moving coordinate system to overcome the difficulty existing in conventional two-pass grinding methods, which separately process the head and neck sections, fail to meet the machining demands for helical grooves in tools with such micro-scale structural features. The method is governed by dual kinematic constraints: a grinding constraint to ensure cutting edge accuracy and an envelope constraint to define the groove profile. By employing an offset coordinate transformation, the wheel trajectory is resolved into the corresponding machine tool axis movements. Simulation and experimental validation demonstrate maximum deviations of 1.25% in cutting edge accuracy and 2.59% in normal rake angle, confirming the proposed algorithm’s correctness. This research provides a theoretical foundation for the design and fabrication of cutting tools with intricate microstructural geometries.</p>