About this Abstract |
| Meeting |
2026 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2026)
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| Symposium
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2026 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2026)
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| Presentation Title |
An In-situ Test Artifact for Real-time Residual-Stress Monitoring and Mechanical Property Correlation in Laser Powder Bed Fusion |
| Author(s) |
Sina Nejati Eghteda, Albert C. To |
| On-Site Speaker (Planned) |
Sina Nejati Eghteda |
| Abstract Scope |
Real-time monitoring of laser powder bed fusion (LPBF) typically relies on pyrometric, acoustic, or synchrotron-based instrumentation that is expensive and rarely couples to part-level mechanical performance, while conventional ex-situ qualification returns feedback only after the build completes. This work introduces a small, geometrically simple test artifact, the V6.0 design, co-printed on the build plate and engineered to fracture at a predictable build layer determined by the local thermal and residual-stress state. The artifact pairs a 0.8 mm × 0.8 mm tensile ligament between two arms with a hybrid wall-and-column support field and a 0°/180° unidirectional scan strategy that maximizes longitudinal residual stress; the resulting fracture produces a powder-ejection signature detectable by a low-cost camera through the chamber viewport.
Three experiments on an EOS M290 with Inconel 718 validate the concept. Break-layer variation across thirty artifacts correlates with the inert-gas velocity field; scan-orientation rotation from 10° to 90° yields an integer staircase response governed by an analytical cosine partition of longitudinal shrinkage; and stepped 40 W power reductions resolve single-step (~14%) decrements through monotonic break-layer shifts. Co-printed ASTM E8/E8M sub-size bars, custom ligament-geometry bars, and XRD stress measurements on companion 2.0 mm artifacts link the in-situ signal to ex-situ properties.
A new Stress Build-Up Rate metric (fracture stress per arm layer) correlates with laser power at r = +0.95 and XRD residual stress at r = +0.88, independent of plate position. The dataset decomposes process state into three orthogonal channels and reveals a 5–8% recoater-direction asymmetry from powder-spread gradients. |
| Proceedings Inclusion? |
Planned: Post-meeting proceedings |