Overhang-Constrained Bezier Strut Optimization for Body-Centered Cubic Lattice Structures in Additive Manufacturing

Abstract

Support structures in laser powder bed fusion (LPBF) increase build time, material waste, and post-processing burden, and are particularly problematic for internal lattice geometries where access for removal is limited. We present a manufacturability-driven optimization of body-centered cubic (BCC) lattice unit cells that reduces support-critical downward-facing surfaces by minimizing a differentiable, normalized overhang-violation metric subject to relative density control. Strut radii are parameterized with cubic Bézier curves using four control radii, enabling asymmetric, variable-thickness profiles while preserving periodicity. Effective elastic properties are computed via computational homogenization with periodic boundary conditions. Across target relative densities (0.20 to 0.45), cell sizes (2 and 3 mm), and overhang thresholds (40, 45 and 50 degrees), the method achieves up to a 9.5% reduction in the normalized overhang-violation metric for cell sizes of 2 mm and above while maintaining or improving homogenized stiffness.