By Stuart Adams, Regional Executive Director-EMEA at Mastercam
For more than a decade, 3D printing – also known as additive manufacturing – has been positioned as the future of aerospace production. With a unique capability to produce complex forms at unparalleled speed, additive manufacturing promised increased production, fewer constraints, and an innovative way to manufacture flight-critical parts.
In theory, additive manufacturing offered aerospace a workaround of traditional constraints. Complex internal geometries, reduced material waste, and unprecedented design freedom seemed poised to redefine the production process when it came to aircraft parts.
But in aerospace, technology needs more than just promise.
Why Accessibility Created Unrealistic Expectations
Part of additive manufacturing’s challenge is a result of its own success. The catch-22 is this: entry-level and hobby-grade 3D printers have lowered the barrier to entry so significantly that some engineers and designers assume the technology will scale seamlessly. This assumption has gotten a foothold across industries.
However, printing a part and producing a qualified, dimensionally precise, structurally reliable component are two fundamentally different challenges. Aerospace parts must meet demanding requirements for tolerance, surface finish, strength, and repeatability. While there is a widespread belief (or hope) that additive manufacturing can serve as a single, end-to-end production solution in aerospace. In reality, it cannot.
Additive’s Real Strengths and Limits
Discernment is key here. A realistic take on additive manufacturing’s limits is important and also doesn’t diminish the value of this approach when utilised appropriately. Where does additive excel? In rapid iteration, early-stage prototyping, weight reduction, and the creation of internal geometries that would be impossible or impractical to machine traditionally.
Where additive falls short is at the finish line. Flat faces, tight tolerances, controlled surface finishes, and consistent geometric accuracy remain difficult to achieve with additive alone, and particularly at the scale required for aerospace. These are not secondary requirements; they are fundamental to safety, performance, and certification.
This is where CNC machining comes in as the essential foundation that turns innovative designs into airworthy parts.
CNC Remains the Manufacturing Standard
Nearly every successful aerospace project relies on CNC machining at some point. CNC machining – also known as subtractive manufacturing – allows parts to meet tolerance requirements, achieve proper surface finishes, and satisfy the exacting standards demanded by flight-critical applications.
In practice, additive manufacturing isn’t a replacement for CNC manufacturing – and it also tends to be more expensive. What additive should be is a complementary approach within existing manufacturing processes. In aerospace today, subtractive manufacturing remains the standard. In fact, it is subtractive manufacturing that makes parts created through additive manufacturing usable on an actual functioning assembly.
The Rise of Hybrid Manufacturing Workflows
The future isn’t additive versus subtractive, it’s additive plus subtractive, each doing what it does best.
In hybrid workflows, parts are printed to leverage additive’s geometric freedom, then machined to meet aerospace-grade tolerances and finishes. The result is the best of both approaches: design innovation without compromising the precision that keeps aircraft in the air.
Hybrid only works when engineers understand both sides. Without machining knowledge, it’s easy to design parts with sharp internal corners, impossibly tight tolerances, or features that balloon costs without improving performance. The most effective hybrid programs are built by teams fluent in both additive possibilities and subtractive realities.
This reflects a broader truth in aerospace manufacturing: choose the right tool for each stage of production. Additive opens new design territory. CNC machining makes those designs flight-ready. Until additive can consistently meet aerospace certification requirements on its own, CNC machining will remain the essential second half of that equation.
What Actually Delivers in Aerospace
Additive manufacturing will continue to evolve, and it should. The technology has earned its place in aerospace for prototyping, weight reduction, and geometric innovation. But when it’s time to deliver parts that meet tolerance, pass inspection, and perform under the demands of flight, CNC machining remains the standard.
The most successful aerospace programs aren’t waiting for additive to catch up. They’re building hybrid workflows that leverage both technologies for what they do best. Additive pushes design boundaries. CNC machining turns those designs into certified, flyable hardware.
That’s not legacy thinking. That’s how aerospace parts actually get made.
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