The Sustainment Crisis
Military readiness depends on spare parts. When a fighter jet sits on the tarmac waiting for a replacement component, when a ship cannot deploy because a critical pump housing is on backorder, or when a forward-deployed unit cannibalizes one vehicle to keep another running — these are sustainment failures with direct operational consequences. The Department of Defense spends over $90 billion annually on maintenance and sustainment, and readiness rates for many legacy platforms remain below targets.
The root cause is a supply chain designed for peacetime efficiency rather than wartime resilience. Many defense components are produced by sole-source manufacturers using tooling that was created decades ago. When that tooling wears out, when the manufacturer exits the market, or when demand surges during a crisis, the system breaks. Lead times for some cast and forged metal components stretch to 18 months or longer. For platforms that will remain in service for decades, the sustainment challenge only grows more acute over time.
Additive manufacturing — commonly known as 3D printing — offers a fundamentally different approach. Instead of maintaining vast inventories of spare parts or waiting months for traditional manufacturing, the digital file for a component can be stored indefinitely and printed on demand, at the point of need, when the part is required.
From Prototyping to Production
Additive manufacturing has moved well beyond the rapid prototyping applications that first brought it attention in the defense community. Metal additive processes — including laser powder bed fusion, directed energy deposition, and binder jetting — can now produce functional components in titanium, Inconel, stainless steel, and aluminum alloys with mechanical properties that meet or exceed cast equivalents.
The U.S. Navy, Army, and Air Force have all invested in additive manufacturing programs aimed at sustainment applications. The Navy's Print the Fleet initiative has deployed additive manufacturing capabilities aboard ships. The Army has fielded expeditionary manufacturing units capable of producing parts in forward locations. These are not experiments — they are operational capabilities being used to solve real sustainment problems.
The technology is maturing rapidly. Multi-material printing, topology optimization that designs parts specifically for additive processes, and AI-driven process monitoring that detects defects during production are all advancing the state of the art. The question is no longer whether additive manufacturing can produce defense-relevant components. It is whether the qualification and certification infrastructure can keep pace with the technology.
The Qualification Challenge
The greatest barrier to widespread adoption of additive manufacturing in defense sustainment is not the technology itself but the qualification and certification process. Defense components must meet rigorous standards for material properties, dimensional accuracy, fatigue life, and environmental resilience. The testing and qualification frameworks for traditional manufacturing processes — casting, forging, machining — have been refined over decades. Equivalent frameworks for additive manufacturing are still being developed.
Each new material-process-geometry combination requires qualification testing that can take months and cost hundreds of thousands of dollars. For a one-off replacement part on a legacy platform, this cost may exceed the value of the part itself. The defense community needs qualification approaches that reduce this burden without compromising safety — statistical methods based on process monitoring data, qualification by similarity to previously tested geometries, and digital twin models that predict performance based on manufacturing parameters.
NIST, ASTM, and the defense services are all working on these frameworks, but progress is measured in years while sustainment needs are measured in days. Bridging this gap requires organizations that understand both the manufacturing technology and the regulatory environment well enough to navigate qualification efficiently.
Distributed Manufacturing and Resilience
Beyond solving individual parts shortages, additive manufacturing offers a strategic benefit: distributed production. Instead of relying on a small number of specialized foundries and machine shops, the digital files for critical components can be maintained in secure repositories and manufactured at any qualified facility — including forward-deployed locations.
This distributed model fundamentally changes the resilience calculus. A supply chain that depends on a single factory in a single location is vulnerable to everything from natural disasters to adversary targeting. A supply chain that can produce critical components at dozens of locations worldwide is inherently more resilient against disruption.
Realizing this vision requires investment in secure digital thread infrastructure — the systems that manage, version-control, and distribute manufacturing files while protecting intellectual property and ensuring that only authorized facilities produce components. It also requires a network of qualified manufacturing sites with consistent processes and quality controls. The technology to print parts is available today. The infrastructure to do so securely, consistently, and at scale is the work that will determine whether additive manufacturing transforms defense sustainment or remains a promising capability used only at the margins.
