A level-set based adaptive refinement approach for topology optimization considering 5-axis milling constraintsOA

Recent advances in topology optimization have highlighted the importance of integrating design and manufacturing considerations.While much of the existing work has focused on additive manufacturing,there is growing interest in exploiting the capabilities of multi-axis machining as part of design for manufacturing.In particular,modern 5-axis CNC milling machines offer substantial geometric flexibility by enabling tool access from multiple orientations,making them well suited for fabricating topology-optimized components with complex features.However,most existing methods rely on a limited set of predefined milling directions,and extending them to arbitrary tool orientations often incurs significant computational cost.This paper presents a practical adaptive framework,based on the level-set method,for handling discretized arbitrary milling access directions in topology optimization.At each iteration,the boundary velocity field is first computed without manufacturing constraints.Tool accessibility is then evaluated,and the velocity field is adaptively modified to enforce manufacturability while minimizing performance degradation.Rather than embedding milling constraints directly into the optimization formulation,the proposed approach applies incremental,localized corrections.A key contribution is the incorporation of a manufacturing-feasibility update loop into the approximate problem,which enhances computational efficiency.The proposed method has been implemented in the commercial code OptiStruct.Numerical examples demonstrate that the resulting 5-axis milling designs closely match unconstrained topology optimization solutions in both geometry and performance.The results indicate that the design freedom offered by 5-axis milling can,in most cases,be effectively utilized to obtain manufacturable designs with negligible performance penalties.