Machining process and parametric geometric characterization of functional edges in valve spools

Spool valves are extensively employed in servo control systems for aerospace and other engineering applications, where their flow control precision is highly sensitive to the micro-geometry of their functional edges, particularly in small-opening regions. This study investigates the machining and parametric geometric characterization of these edges. Through the measurement of burr dimensions following grinding experiments, the influence of process parameters on burr formation was systematically examined. To address the limitations of manual deburring, an in-situ deburring device based on constant-force removal was developed, and a recommended deburring force for the fine-grinding range was identified experimentally. On this basis, a function-oriented parametric characterization method is proposed, which establishes a link between the geometric features of the edge and its flow–displacement characteristics through theoretical analysis and numerical simulation. The proposed method was further applied to evaluate valve spool edges by measuring the functional edges resulting from both manual and in-situ deburring processes. The results demonstrate that the in-situ deburring process significantly enhances edge quality compared to manual techniques. Moreover, the proposed characterization method offers a quantitative framework for evaluating the micro-geometry of functional edges.