Ti Gr.23. Inconel 718. 316L. CoCr. Complex geometry.

Metal 3D printing is expensive. Small Ti bracket: $500-2,000 per part. Medium part: $2,000-10,000. Large aerospace bracket: $10,000+. Compared to CNC equivalent: 3-10× cost. Justify when: (1) geometry impossible to machine (internal channels, lattices), (2) topology-optimized design enables weight savings that justify cost, (3) very low quantity of very complex parts. For most applications, CNC is more cost-effective.

DMLS/SLM: ±0.1-0.3 mm typical, depends on part size and thermal conditions. Better on small parts, worse on large. For tight tolerance features (bearing fits, mating surfaces), post-machining required. Standard workflow: 3D print → heat treat → HIP (if required) → post-machine critical features. This combines 3D printing's geometry freedom with CNC's precision.

As-printed metal parts have internal stress and porosity (0.5-2%). Stress relief heat treatment after printing: reduces residual stress. Full heat treatment (solution + aging): achieves full material properties. HIP (Hot Isostatic Pressing): eliminates porosity for aerospace/medical certification. Typical aerospace workflow: print → stress relief → HIP → solution + age → post-machine. Each step adds 5-10 days to lead time.

Metal 3D printed aerospace parts require qualification: AMS 7003 for material, specific customer qualification for each part. Qualification involves: mechanical testing of coupons from each build, NDE (non-destructive evaluation) of parts, chemistry verification, fatigue testing. Qualification establishes process capability. Post-qualification, individual parts tested per customer spec.

DMLS build envelopes vary by machine: 250 × 250 × 300 mm typical for our capability. Large parts split into sub-components with welding/brazing. Multiple small parts nested in single build for cost efficiency. Typical build cycle 12-48 hours depending on part height and complexity. Post-print processing (powder removal, support removal, heat treatment, machining) adds several days.

As-printed: Ra 6-12 µm with stair-step from layer lines. Post-processing options: bead blast (uniform matte Ra 3-6 µm), chemical milling (smoother), tumbling (general), machining (CNC finish Ra 0.8 µm on critical surfaces). For aerospace parts, CNC post-machining of mating surfaces standard — ensures dimensional accuracy and required finish.