Metal powder bed fusion remains the dominant route in metal 3D printing. On the equipment side, parameter races are underway around multi-laser systems, large formats, copper alloys, and highly reflective materials, while research focuses on hard-demand scenarios such as lattice structures, point lattices, heat exchangers, and lightweight supports. Some teams have packed in-situ monitoring tools — acoustic emission, melt-pool radiance, and high-speed cameras — into the build chamber, attempting early stopping before interlayer lack-of-fusion evolves into irreversible defects. A printed metal part is only a semi-finished product; heat treatment, hot isostatic pressing, machining, and support removal each add cost, and the process window is narrow: too low a temperature leaves residual stress incompletely relieved, while too high a temperature causes grain growth and degraded properties. Oxygen-content stability after multiple powder reuse cycles and control of multi-laser stitching zones are the real engineering challenges on the equipment side. The continuous-fiber route is constrained by path planning and anisotropy, and interfacial wetting, porosity control, and fiber-orientation prediction have yet to yield reliable allowable-value databases. The implications for the metal additive manufacturing supply chain are direct: the focus of competition is shifting from "can it be printed" to "can it serve reliably after printing," and process-window repeatability, defect statistics and fatigue life, and standards and data traceability have become the thresholds for moving from prototypes to production lines. Equipment parameters, powder condition, and post-processing must be managed as a single chain; single-point breakthroughs can hardly support volume delivery. Value for powder buyers: ① Pay attention to oxygen-content stability data after powder reuse and require suppliers to provide batch consistency reports after multiple reuse cycles; ② For popular categories such as copper alloys and highly reflective materials, lock in powder sources with particle-size distribution and sphericity control capabilities in advance; ③ Incorporate powder recycling and quality traceability into procurement agreements to ensure each powder batch can be linked to the printing process window and final-part performance validation.