Velo3D: How Metal Additive Manufacturing for Aerospace Demands a New Kind of Systems Engineering at the Part Level
When manufacturing freedom expands, requirements management has to keep up — and most teams aren’t ready.
The Problem With “Design for Additive” as a Slogan
Metal additive manufacturing has spent a decade promising to unlock geometries that traditional machining cannot produce. That promise is real. Rocket combustion chambers with conformal cooling channels, turbine components with internal lattice structures, hydraulic manifolds that eliminate dozens of brazed joints — these are not theoretical. They exist in flight hardware today.
But the slogan “design for additive” has obscured a harder engineering truth: when you change what is manufacturable, you change what is specifiable. Requirements that were written to constrain geometry relative to a machine’s cutting radius now need to constrain geometry relative to a build parameter envelope. Requirements that captured material properties from certified mill stock now need to capture properties that emerge from a specific laser power, scan speed, and layer thickness combination.
This is not a manufacturing problem. It is a systems engineering problem. And it shows up most acutely in the work of Velo3D, whose approach to selective laser melting has pushed the printable design space further than most aerospace and defense customers were prepared to specify.
What Velo3D Actually Does
Velo3D builds industrial metal AM systems — printers, process software, and quality assurance workflows — focused on the production of complex metal parts in materials like Inconel 718, Ti-6Al-4V, and aluminum F357. Their differentiation is technical and specific: their Sapphire series machines can print low-angle overhangs and near-horizontal internal surfaces without support structures.
Support structures in metal AM are not a minor inconvenience. In standard laser powder bed fusion, any surface angled more than roughly 45 degrees from vertical requires a support — a printed scaffolding that must later be removed. For parts with internal channels, that removal is often impossible, or requires design compromises that eliminate the geometric advantages AM was supposed to provide. For rocket engine components with complex internal cooling geometries, this constraint historically forced compromises on channel routing that directly impacted thermal performance.
Velo3D’s process — which they brand as Intelligent Fusion — uses a combination of recoater blade geometry, gas flow management, and closed-loop melt pool monitoring to print angles as low as 5 to 10 degrees from horizontal without supports in many configurations. The result is that geometries previously excluded from AM are now in scope.
Customers including Launcher (now Vast), Honeywell, Boom Supersonic, and Lockheed Martin have used Velo3D systems to produce parts that were either impossible with prior AM processes or required extensive post-processing that eroded cost and lead time advantages.
The Systems Engineering Implications Nobody Warned Customers About
1. When the Manufacturing Constraint Disappears, Where Does the Requirement Come From?
In conventional aerospace manufacturing, the machine shop’s capabilities are a known input. A designer knows what minimum wall thickness is machinable, what internal radii a cutting tool can produce, what surface finish is achievable without secondary operations. These constraints are embedded — often implicitly — in the requirements written by the systems engineering team.
When Velo3D removes the support structure constraint, a significant class of design constraints disappears. That sounds like pure gain. It is, for performance. But it creates a gap in the requirements process: the constraint that previously lived in manufacturing DFM guidelines now has to be replaced with a constraint derived from the printer’s parameter envelope, and that envelope is not a fixed number. It depends on material, part geometry, part orientation, and build strategy.
The result is that customers who transition to Velo3D systems without updating their requirements practices find themselves writing functional requirements that their parts can technically meet through geometries that the printer cannot reliably produce — or can produce but not yet in a qualified process. The requirement says nothing wrong. The part drawing says nothing wrong. The build fails process qualification.
This is not a Velo3D problem. It is a requirements methodology problem that Velo3D’s capability has surfaced.
2. Material Qualification Is a Continuous Input, Not a One-Time Gate
In traditional aerospace manufacturing, material qualification follows a well-established path: certify the mill run, establish allowables from MMPDS or equivalent, apply statistical knockdowns, write requirements that reference the allowable. The process is linear, the qualification is stable, and the requirements can be written once and baselined.
Metal AM inverts this. Material properties in laser powder bed fusion are a function of process parameters. Inconel 718 printed at one laser power and scan speed has different microstructural characteristics than Inconel 718 printed at another. When Velo3D updates its process software — which includes parameter sets developed to extend geometric capability — the material properties produced by that process can shift. Not dramatically, in a well-controlled system. But enough to require re-verification against requirements.
This means that requirements for AM parts cannot simply reference a material designation. They have to reference a material-process combination. And they have to be structured so that when the process evolves, the impact on compliance can be assessed traceably.
For aerospace customers working to AS9100, NADCAP, or FAA regulatory frameworks, this creates a documentation architecture problem. The requirements baseline is entangled with the process baseline in ways that traditional requirements management tools — built around document-centric, static requirement statements — handle poorly. Changing a Velo3D parameter set to improve overhang capability on a specific feature triggers a change analysis that has to touch requirements, material specs, inspection criteria, and test plans simultaneously.
Teams that manage this well have started treating the print process parameter set as a formal design input that is captured in the requirements model, not just in the manufacturing plan. That is a significant organizational and tooling change.
3. Printability Requirements and Functional Requirements Are Not Separate Documents
The most operationally significant shift Velo3D’s customers face is the need to write requirements that simultaneously constrain functional performance and manufacturing feasibility in the same requirement space.
A cooling channel in a rocket combustion chamber has a hydraulic diameter requirement derived from thermal analysis. It has a surface roughness requirement derived from flow and heat transfer models. And it now has a geometric freedom requirement — or more precisely, the absence of a geometric constraint — that must be stated in terms of what the Velo3D build process can qualify for that feature.
If these three sets of constraints live in separate documents — functional spec here, manufacturing plan there, process qualification elsewhere — then the traceability chain required to demonstrate compliance becomes a manual reconciliation exercise. Engineers spend time in spreadsheets cross-referencing documents instead of identifying conflicts early.
The customers who have handled this most effectively have restructured their requirements architecture so that printability constraints exist as formal derived requirements, linked to functional parents, and traceable to process qualification data. This is not a theoretical best practice. It is the only way to manage change without rebuilding the compliance case from scratch every time a build parameter changes.
How Velo3D Works With Customers on This
Velo3D’s customer engagement model includes what they call a print qualification process: working with the customer to define which geometries and material conditions are within the validated process envelope for a given program. This is not a standard vendor relationship. The printer manufacturer is participating in requirements definition — specifically, in defining the bounds of what can be committed to as a requirement on a flight part.
This collaborative printability scoping happens before the functional requirements are finalized on complex programs. Velo3D’s applications engineering team works through design reviews where geometric features are assessed against the current process envelope, and features that would push outside that envelope either trigger process development work or design iteration. The output of that process is effectively a set of printability requirements — documented limits on geometry, feature orientation, and wall thickness — that constrain the design space within which functional requirements can be written.
In practice, this means the Velo3D application engineer is a de facto systems engineering participant on the customer’s program. That is a significant departure from how aerospace manufacturers have historically worked with machine vendors.
For customers with mature systems engineering practices, integrating this input requires extending their requirements model to accommodate a new source of derived requirements. For customers with less mature practices — or practices built around document management rather than model-based approaches — it often results in the printability constraints living in email threads and meeting notes rather than in the formal requirements baseline.
What Current-State Requirements Practices Get Wrong
The majority of aerospace requirements management practices in use today were built on assumptions derived from subtractive manufacturing: that the manufacturing process is a fixed constraint applied after design, that material properties are looked up from a certified table, and that the requirements baseline and the manufacturing baseline are separate artifacts that interface at a defined handoff point.
Metal AM in general, and Velo3D’s expanded design freedom in particular, violates all three assumptions. The manufacturing process is not fixed — it is a co-designed variable. Material properties are not looked up — they are produced. The handoff between design and manufacturing is not a discrete event — it is an ongoing negotiation that runs through qualification.
Requirements tools that manage requirements as text in a hierarchical document, with traceability implemented as links between document sections, are structurally insufficient for this. They can capture the requirement. They cannot capture the requirement’s dependency on a process parameter, flag a compliance risk when that parameter changes, or propagate the impact of a material allowable update through the affected requirement set without manual intervention.
The systems engineering discipline has the concepts — model-based systems engineering, parametric constraints, bidirectional traceability — to handle this properly. The gap is in adoption, particularly among the mid-tier defense and aerospace suppliers who are early adopters of Velo3D systems precisely because they are trying to compete against larger primes on part complexity and lead time.
What Good Looks Like
The engineering teams that have navigated this transition successfully share a few characteristics worth naming.
They define printability as a requirement class, not a manufacturing note. Features that have geometry constraints derived from the print process are written as formal requirements with clear rationale and traceable links to process qualification data.
They treat the Velo3D process parameter set as a versioned design input. When Velo3D releases updated process software, they run a formal impact assessment against their requirements baseline, the same way they would assess a material specification change.
They maintain a live connection between their requirements model and their material qualification data. When coupon test results update the allowable for a specific process-material combination, the delta is assessed against the requirements that reference that allowable — not reconstructed from memory during a compliance review.
Tools like Flow Engineering, which implement graph-based requirements models with bidirectional traceability and support for parametric relationships between requirements, represent the architecture that makes this tractable. The ability to capture a functional requirement, derive a printability constraint from it, link both to the process qualification they depend on, and propagate change impacts automatically is not a luxury for programs with complex AM parts — it is a prerequisite for managing the qualification efficiently.
Honest Assessment
Velo3D has solved a meaningful manufacturing problem. Low-angle printing without supports is real capability that enables real parts that are meaningfully better than what alternative processes can produce. The aerospace and defense customers using these systems are producing hardware that performs better, weighs less, and eliminates assembly joints that were failure modes.
The systems engineering discipline has not kept pace. Requirements practices built for traditional manufacturing are being applied to AM-designed parts with light modification, and the gaps are showing up as slow qualification cycles, rework when process parameters change, and compliance cases that are fragile under audit.
The companies that will extract the full value of Velo3D’s manufacturing capability are the ones that restructure their requirements methodology to treat printability as a first-class constraint class, process parameters as versioned design inputs, and material qualification as a continuous feedback loop rather than a one-time gate.
That restructuring is not primarily a technology investment. It is an engineering practice change. The technology to support it exists. The organizational will to adopt it is the actual limiting factor.