Optimization of snap-fit geometry for fused deposition modeling process

초록

Fused deposition modeling (FDM)-based snap-fits exhibit process-induced orthotropy that limits direct use of isotropic design guidelines. We present an FEA-based, target-driven framework that explicitly accounts for the orthotropy of polylactic acid (PLA) to optimize the geometry of a cantilever snap-fit. Thickness (t), width (b), and fillet radius (r) are optimized to meet targets of tip displacement 1.0 +/- 0.1 mm and safety factor 1.2 +/- 0.1 under a 20 N pinch force. The resulting design (t = 10.0 mm, b = 2.3 mm, r = 3.1 mm) achieved 0.99 mm tip displacement and minimum safety factor 1.17 in simulation. An FDM-based prototype was manually assembled and disassembled, showing elastic engagement within the target displacement and no cracking or permanent set, supporting the analysis. The framework returns geometries that meet displacement and safety factor targets and offers a practical route to application-specific snap-fits produced by FDM.

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