Flank milling, valued for its superior surface finish and high efficiency, holds a key position in computer-aided manufacturing (CAM). However, a significant gap persists between industry and academia: industrial solutions rely on mature yet closed systems that hinder further advancement, while academic research often focuses on isolated performance metrics without full-chain implementation, limiting practical applicability. To address this, this paper proposes a novel end-to-end modular flank milling framework, synthesizing advanced academic research and industrial practice. Compared with popular commercial software, the proposed method generates superior and flexible tool paths; compared with typical academic methods, it features higher completeness and practical application value. Additionally, it supports users in embedding specific optimization methods to build an open-source ecosystem, ultimately bridging the gap between the two sectors and driving the next-generation upgrade of side milling technology.