Qualifying an additive part means qualifying everything upstream of it
Properties depend on machine, powder lot, build location, orientation and thermal history. That makes the qualification unit a process, not a part.
Qualifying a machined component is well understood: material certification, dimensional inspection, and a manufacturing process that does not fundamentally alter bulk properties. Additive manufacturing creates the material and the geometry simultaneously, which invalidates that separation.
What varies
Machine to machine. Nominally identical machines produce measurably different properties owing to laser calibration, gas flow and thermal environment.
Powder lot to powder lot. Chemistry, size distribution and morphology vary within specification, and those variations affect the result.
Location on the plate. Gas flow across the build removes spatter and vapour, and it is not uniform. Parts at different positions experience different conditions.
Orientation. Layer-wise construction produces anisotropic properties. Strength along the build direction differs from strength across it, and fatigue behaviour differs more.
Build content. Thermal history depends on what else is on the plate, because heat from neighbouring parts affects local cooling rates.
That last point is the awkward one. A part's properties can depend on what it was built alongside, which means a qualified configuration may include the build layout.
What qualification therefore covers
Rather than certifying parts, additive qualification certifies a frozen process: specified machine, specified powder specification and reuse protocol, specified parameters, specified orientation and location, specified post-processing and heat treatment.
Witness coupons built alongside production parts provide per-build evidence, and any change to any element triggers requalification.
The cost consequence
That rigidity is why additive works economically in aerospace and medical for parts where geometry provides substantial value, and poorly where it is merely an alternative production route. The qualification cost is largely fixed per part number, so it amortises over volume but must be paid regardless.
It also explains why manufacturers resist machine upgrades and parameter improvements on qualified parts. A better process is not better if it costs a requalification campaign.
Where standards have helped
Industry standards for powder, process control and testing have reduced the burden by defining common requirements. They have not removed it, because the underlying coupling between process and material properties is physical rather than procedural.
This article was produced by the LasersNews AI desk and reviewed by our editors.
Related reading
Multi-laser powder bed fusion hits a qualification gap, not a hardware one
Machines with four, eight and twelve lasers are shipping. Proving that a part is identical wherever it was bu…
Multi-laser powder bed fusion has a seam problem at the overlap
Four, eight and twelve laser machines divide the build area between sources. Where their territories meet, th…
Powder reuse economics run into oxygen pickup
Unfused powder is most of what goes into a build. Reusing it is essential to the business case and gradually…