Qualification Test Artifact

Artifact Overview
This compact artifact occupies a build volume of roughly 40 × 39 × 40 mm (x, y, z), with a total solid volume of about 25 cm³. It includes:
• Geometric features (thin walls, pins, holes, lattice structures, angled overhangs) to evaluate dimensional accuracy and minimum feature sizes.
• Detachable chemical-analysis coupons with enough material for oxygen, nitrogen, and ICP-based chemistry tests.
• Built-in subsize tensile bars (ASTM E8 style) to allow for direct testing of mechanical properties without additional machining steps.
• Internal channels (both straight and helical) and lattice regions to check powder removal effectiveness and investigate internal surface quality.

Recommended Build Instructions
• Orientation: Align the part so that its base edges and overhanging surfaces are at 45° to the recoater blade (or powder-flow) direction. This orientation helps minimize contact between the recoater and tall or thin features, and it positions the artifact’s thin walls, pins, and angled overhangs optimally for data collection.
• Layer Thickness: A 30 µm layer thickness is recommended for good resolution on fine features. Other layer thicknesses are possible, but excessively thick layers can obscure small channels and compromise dimensional accuracy.
• Support Structures:
– Include standard block or wall supports under the wide overhang and island features.
– For the residual-stress overhang, keep support contact minimal so it can be easily removed by hand or cut to allow measurement of released curvature.
– Ensure that the helical channel and lattice structures have enough venting to remove unfused powder; otherwise, incorporate small openings or exit holes that facilitate powder evacuation.
• Nesting Multiple Artifacts: If build platform space permits, consider printing several artifacts at once, positioning them at different locations to identify system-level variations across the build plate.
• Powder Removal and Post-Processing:
– Use compressed air, ultrasonic baths, or other shaking/vibratory methods to clear powder from internal channels and lattice structures.
– For thorough verification, consider CT scanning or other nondestructive evaluations, especially when evaluating difficult-to-clear regions.
• Cooling and Handling:
– Allow the build plate to cool sufficiently to minimize residual stresses upon part removal.
– If performing stress-relief heat treatments, apply them before removal from the build plate to reduce the likelihood of warping or cracking.

Printing Tips & Troubleshooting
• Scan Strategy: Tailor your contour/infill strategy (number of contour passes, stripe/spot overlap, downskin settings) to minimize edge-related defects. For instance, short or overlapping scan vectors can introduce near-edge porosity or roughness.
• Atmosphere Control: Monitor oxygen content in the build chamber. Ti-6Al-4V, in particular, can pick up oxygen quickly, affecting mechanical properties. The detachable chemical coupons are designed for measuring and tracking this pickup.
• Sectioning: Indication marks on the artifact’s exterior help with consistent sectioning for metallography. Ensure a clean, precise cut in each plane so that microstructural features (e.g., thin overhang walls, lattice struts) remain intact for analysis.
• Residual Stress/Distortion:
– Observe the “island” features for layer mismatches or small steps where the island rejoins the main body—this is a quick visual check for distortion.
– After cutting the thin support structures from the residual-stress overhang, measure and record its curvature profile to quantify stress release.

Use with Other Technologies
Although specifically designed to accelerate LPBF process qualification, many elements in this artifact (e.g., thin walls, channels, overhangs, tensile coupons) can still be valuable with other powder-bed processes, such as electron beam powder bed fusion or binder jetting. Some features—like the internal channels and lattice zones—could be adapted to polymer-based or hybrid AM methods to compare geometry, residual stress, and mechanical behavior across different platforms. The same fundamental data (surface roughness, distortion, defect density, mechanical properties) remain relevant whenever layer-by-layer consolidation is involved.