Defence shifts from stockpiling spares to manufacturing them on demand

For decades, defence planners have assumed that the safest way to support ageing platforms is to hold more spare parts. But as military systems remain in service for 30, 40 or even 50 years, the industrial base behind them often shrinks far sooner. Suppliers withdraw, tooling is discarded, minimum order quantities become uneconomic and once-common components drift into obsolescence.

That mismatch is forcing a rethink. Rather than relying solely on large warehouses full of rarel...

y used parts, a growing number of defence organisations are exploring a digital-first model that preserves the ability to reproduce components when they are actually needed. The idea is simple: keep the manufacturing knowledge in digital form, then use on-demand production to turn that data back into a physical part.

Traditional spare-parts logistics has long struggled with unpredictability. Equipment failures are not evenly distributed, and stockpiling every conceivable replacement is expensive, space-intensive and often wasteful. Some items may never be issued, while others may fail unexpectedly and expose an abrupt gap in supply. Once that happens, restarting production can mean recreating drawings, requalifying processes, finding new suppliers and, in some cases, redesigning the component for current manufacturing methods.

That is why digital inventories are attracting attention. Instead of treating every spare as a physical item that must be stored in advance, organisations can hold approved digital files and the associated production information needed to manufacture parts later. In effect, the inventory becomes a managed capability rather than a shelf full of hardware. Physical stock still has a place, especially for high-use or mission-critical items, but long-tail and low-demand components can be shifted into a digital reserve.

According to Shapeways, which has been promoting this approach through its defence programme, the value of digital inventory only becomes real when it is paired with manufacturing capacity. Additive manufacturing and CNC machining can both support small batches or single-unit production without the overhead of a dedicated line for every part. That matters in defence, where demand is often irregular and volumes are modest. A vessel may need one housing, not hundreds; an older system may require a bracket that has not been made for years.

Obsolescence is one of the most persistent problems in legacy programmes. A platform may remain operational long after the commercial life of its components has ended, leaving the maintenance authority to cope with discontinued suppliers or vanished tooling. In response, some organisations resort to last-time buys, cannibalising equipment or funding expensive redesigns. A digital-first model creates another route: where technically appropriate and properly qualified, a legacy component can be reverse-engineered or adapted for modern production methods and then stored as a controlled digital asset.

Low-volume economics are another reason the model is gaining traction. Conventional manufacturing is usually built around scale, tooling and predictable order patterns. Defence spare parts rarely fit that template. When only a few units are required, the cost and lead time of restarting a traditional supply chain can look disproportionate to the value of the item itself. Digital manufacturing reduces that burden by removing much of the tooling requirement and bringing production closer to the moment of demand.

Speed is only part of the equation. Resilience matters too. Recent supply-chain shocks have exposed the risks of depending on a single factory, a single tool or one geographically concentrated source of production. A digitally governed spare-parts system can separate the design data from any one location, allowing approved parts to be produced across multiple qualified sites. For defence customers, that can help with capacity constraints, disruption and, in Europe, wider ambitions around industrial sovereignty and regional supply resilience.

The wider industry is moving in the same direction. Platforms from companies such as Fieldnode, Pelagus and Vistory all point towards a similar model: selected physical stock replaced by governed digital assets, traceable workflows and distributed manufacturing closer to the point of use. Sparely.ai also pitches spare-parts production as a service, using automation and localised manufacturing to support continuity while reducing waste. Taken together, these offerings reflect a broader shift in thinking, from stockholding as the main defence against uncertainty to manufacturing readiness as the real objective.

That shift is especially relevant for long-life military systems. Defence fleets are expected to endure for decades, but their supporting supply chains often are not. A strategy built entirely around inventory can become fragile as the original industrial ecosystem disappears. A strategy built around digital inventories and on-demand manufacturing is not a replacement for every conventional process, but it does offer a more sustainable answer to the problem of aged platforms, scarce parts and changing supply chains.

The underlying lesson is that readiness is no longer just about what sits in a warehouse. It is about how quickly an organisation can recreate what it no longer has. For defence maintainers, that means identifying which parts genuinely need to be held physically, which can be preserved digitally and how to connect those files to qualified production routes.

Shapeways says the aim is not to eliminate traditional supply chains altogether, but to ensure there is another way to produce a part when the old one no longer works. In an era of ageing fleets and uncertain supply, that may prove to be the more valuable form of stockkeeping.

Source: Noah Wire Services