Metal additive manufacturing (AM) has transcended its initial role as a prototyping tool, emerging as a strategic asset for defense applications, particularly in supporting aging military platforms with complex, low-volume spare parts. The conventional supply chains that have long served these vital systems are increasingly strained, facing challenges like obsolete tooling, vanishing suppliers, and fragile, extended logistics networks. The ability to produce critical metal components near the point of need offers a compelling solution to these vulnerabilities. However, a significant hurdle remains: gaining the trust of defense ministries in the reliability of parts manufactured on-site, without the need for extensive central laboratory inspection and testing.
Addressing this critical gap, the European Defence Fund (EDF)-funded DISCMAM project (Digital Supply Chain for On-Site Maintenance by Additive Manufacturing) has pioneered a transformative approach. Instead of attempting to replicate the complex and resource-intensive testing protocols of central labs in field environments, DISCMAM champions a paradigm shift towards digital qualification. This innovative strategy replaces traditional physical testing with a robust digital framework, ensuring confidence in the quality and performance of additively manufactured parts.
The Dawn of Digital Qualification in Defense AM
The core of the DISCMAM project’s innovation lies in its development of digital quality control for Laser Powder Bed Fusion (LPBF), a leading metal AM process. By integrating in-situ monitoring with the creation of responsive digital twins, the project delivers real-time quality assurance. This sophisticated system combines functional acceptance criteria, artificial intelligence (AI)-driven defect detection, and statistical modeling to classify printed parts into graded acceptance levels immediately after production. This groundbreaking methodology is now being integrated into Fieldmade’s deployable NOMAD03 microfactory, signaling a significant step towards practical, on-site AM implementation for defense.
Moving Beyond Traditional Testing: The DISCMAM Framework
The DISCMAM project’s objective is not to entirely abandon physical testing but to augment and, in many cases, replace conventional, labor-intensive, and often destructive testing methods. Traditional approaches such as tensile testing, micrographic porosity analysis, and full metrology are time-consuming, expensive, and can render the tested part unusable. DISCMAM’s digital qualification leverages the inherent digital footprint generated during the LPBF build process. By capturing data from every layer as it is printed, the project constructs a comprehensive record of the manufacturing process.
The success of this digital qualification relies on three fundamental elements:
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Operationally Meaningful Acceptance Levels: Recognizing that not all parts or missions demand the same level of assurance, DISCMAM has developed a tiered acceptance system. A simple pass/fail against stringent Original Equipment Manufacturer (OEM) specifications is often impractical in theater. Instead, a graded system reflects the expected service life of the component and potential mitigations in its operational use. Crucially, this framework does not necessitate the measurement of absolute material characteristics in the field, which is frequently impossible. Instead, it utilizes relative quality intelligence to build confidence levels. This approach acknowledges that for many field repairs, a part with slightly reduced, but still acceptable, performance characteristics might be perfectly adequate for a critical, short-term mission, whereas a permanent replacement would require the highest assurance.
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Correlated In-Situ Metrics: A sophisticated monitoring system is required to detect and quantify process anomalies. DISCMAM focuses on events such as streaking, spatter, pinning, and warpage. These phenomena have been statistically linked to critical defects like porosity, dimensional deviations, and compromised surface properties. By accurately tracking these in-situ metrics, the system provides early warnings of potential quality issues. For instance, excessive streaking, often caused by recoater blade damage, has been demonstrably correlated with increased porosity and geometric inaccuracies in printed parts.
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Fast-Response Digital Twin: The third essential component is a dynamic digital twin that acts as a real-time quality assessment tool. This digital twin ingests the in-situ metrics and process settings as inputs and, in turn, generates an evidence-based classification of the part’s quality immediately following the build. This allows for immediate decision-making regarding the part’s usability, significantly accelerating repair and maintenance cycles.
Demonstrating the Power of Digital Evidence: Real-World Use Cases
The DISCMAM project has successfully developed and validated all three of these elements using defense-relevant parts printed on an industrial LPBF platform. The Danish Technological Institute (DTI), in collaboration with Euler3D and Fieldmade, has engineered and trialed a digital AM supply chain specifically designed for on-site maintenance. The project focused on two aluminum use cases, provided by the Belgian Ministry of Defence (MoD), both of which were 3D printed using LPBF with AlSi10Mg powder on a Nikon SLM Solutions 280 machine at DTI.
The first use case involved a compressor cover for a Mercedes Unimog heavy truck (specifically, a U1350L air-compressor component). This part is critical for enclosing and sealing a pressurized volume, relying on a gasketed downskin face. Potential failure points include gasket leakage or mechanical cracking, both of which can be exacerbated by subsurface defects or geometric inaccuracies.
The second use case was a fuel filter housing for the same Unimog vehicle. This component is essential for holding fuel filters under slight vacuum upstream of the fuel pump. Imperfect sealing faces or compromised threaded interfaces could lead to vacuum leaks, while structural failures could arise from inadequate strength due to porosity or surface imperfections during handling or under vibration.
These components are emblematic of the challenges faced in defense AM: they possess non-trivial geometric complexity, feature critical surfaces and interfaces, and have well-understood failure modes directly related to porosity, geometry, and surface texture. DISCMAM’s digital qualification approach directly addresses these critical aspects.
Graded Acceptance: Tailoring Quality to Urgency and Function
DISCMAM has translated the technical and operational requirements of these critical use-case parts into a robust set of functional acceptance criteria for LPBF aluminum spares. This resulted in the definition of four distinct acceptance levels:
- Level 1: Permanent Replacement: Parts qualifying for this level meet the highest standards and can be used as direct, long-term replacements for original components.
- Level 2: Temporary Replacement: These parts offer a reliable, but potentially limited, service life and are suitable for situations where immediate permanent replacement is not feasible.
- Level 3: Emergency Use: Components in this category are intended for critical, short-term applications where operational readiness is paramount, and a higher risk tolerance may be acceptable.
- Level 4: Scrap: Parts that do not meet the minimum quality thresholds for any operational use are designated for scrap.
Quantitative ranges were proposed for each level and use case, encompassing parameters such as hardness and Ultimate Tensile Strength (UTS) bands, acceptable roughness limits for both functional and non-functional downskins, and thread torque windows.
A significant challenge acknowledged by both Ministries of Defence (MoDs) and OEMs is the lack of comprehensive legacy data to establish absolute material thresholds. The DISCMAM framework overcomes this by leveraging relative digital evidence to build operational confidence. A key principle is that any digital intelligence indicating poor quality or process anomalies serves as an immediate disqualifier, even for Level 3 emergency use. This is because a process deviation fundamentally compromises the integrity of the production, regardless of other measured parameters.
These graded acceptance levels have become the foundational element of DISCMAM’s LPBF quality assurance strategy. The in-situ monitoring system and the digital twin do more than simply flag "defects"; they actively indicate the likely acceptance level of a part, thereby providing clear guidance on how, and for how long, it can be safely utilized.
From Defect Maps to Actionable Quality Insights
During LPBF builds, Euler3D’s technology captures layer-by-layer images of the powder bed and the exposed surface. Employing a combination of classical image processing and deep neural networks, this system quantifies key defect modes. These include streaking (potentially caused by recoater damage), spatter accumulation, pinning (where powder particles adhere to the surface), warpage or obstruction, smoke events, and local powder loss.
In the DISCMAM project, this capability was deployed and validated on the Nikon SLM Solutions 280 at DTI during the production of the Unimog compressor cover and fuel filter housing. For each printed part, detailed defect frequency plots were generated, illustrating defect distribution over build height. Spatial heatmaps highlighted areas where defects were concentrated across the build plate. Integrated metrics, such as total streaking, spatter count, and overall defect area, provided a quantitative summary of process quality.
These in-situ data were then rigorously compared with post-process physical measurements. These included high-resolution Computed Tomography (CT) scans to assess porosity and geometric deviation (measured against the CAD model), downskin roughness measurements, Profilometry-based Indentation Plastometry (PIP) for local mechanical properties, and hardness testing.
The correlations observed were compelling. Higher levels of streaking and spatter detected by Euler3D’s system were consistently associated with increased porosity and defect indications in CT scans, particularly in functionally critical regions. This confirmed that recoater-induced disturbances serve as reliable proxies for lack of fusion and pore formation. Specimens printed with intentionally damaged recoater lips, resulting in dense streaking signatures, also exhibited elevated geometric deviations when compared to their CAD models via CT. Furthermore, downskin roughness was found to be strongly influenced by streaking patterns, with continuous linear disturbances leading to extended height variations, while localized pinning contributed to sharp protrusions.
On the mechanical front, samples achieving relative densities at or above approximately 99.9%, typically through optimized energy density and gas flow, demonstrated higher yield strength, UTS, and hardness. Conversely, parts with slightly lower densities and higher in-situ defect activity exhibited reduced mechanical performance. Collectively, these results provided strong evidence that Euler3D’s defect maps are accurate early indicators of porosity, geometry, and surface conditions that directly influence functional acceptance.
The Digital Go/No-Go Framework
DISCMAM encapsulated these critical correlations into a fast-response digital twin for LPBF quality classification. This culminated in a digital go/no-go framework, visualized in Figure 3 of the original report. For each build, one or more test coupons are printed alongside the primary target part under identical conditions. Euler3D and DTI collect defect metrics for these coupons and compare them against a reference population of "known good" parts—those that have already undergone comprehensive validation via CT and mechanical testing.
New parts are then assessed by comparing their defect metrics to the distribution of the reference parts. The "distance" from this relative distribution is used to assign the part to one of the four functional acceptance levels agreed upon with the Belgian MoD: Level 1 (permanent replacement), Level 2 (temporary replacement), Level 3 (emergency use), or Level 4 (scrap). Concurrently, layer-by-layer status indicators highlight "potential" or "critical" layers, flagging them for focused review by quality control personnel.
During trials at DTI, including builds of the Unimog compressor cover with accompanying coupons, this framework consistently ranked the coupons within the permanent acceptance region when produced under DISCMAM’s optimized parameters. This enabled the main compressor cover part to be classified as Level 1 without the need for additional CT scanning, while still retaining CT as a validation option. In essence, Euler3D’s in-situ defect detection, with its proven correlation to porosity and geometric deviation, closes the quality assurance loop. It replaces conventional physical inspection with tangible digital evidence, transforming raw defect maps into a practical, data-driven tool for ranking parts into four distinct acceptance levels. This empowers faster, more confident decisions regarding the use of field-printed metal spares.
Accelerating Adoption: The AM Village Workshop in Albacete
To foster knowledge transfer and provide a tangible demonstration of the DISCMAM solution, the project consortium organized a joint workshop at the AM Village 2026 in Albacete, Spain. Hosted by the Spanish Air Force and organized by the European Defence Agency (EDA), the event in March brought together a diverse group of industry, academia, and defense stakeholders. This included representatives from Ministries of Defence and Maintenance and Logistic units from various military forces, underscoring the broad interest in advanced AM solutions for defense.
During the workshop, DISCMAM partners—DTI, Fieldmade, and Lortek—highlighted the critical importance of quality assurance for on-site, deployed AM operations. Participants observed how essential it is to move beyond visual inspection alone, which is incapable of detecting internal quality flaws. Instead, attendees witnessed the identification of a defective part using rapid, digital quality assurance methodologies integrated within Fieldmade’s Nomad03 containerized solution. This practical demonstration proved highly effective, earning Fieldmade AS the "Best Performance" award at the event. This recognition further validated the significance of DISCMAM’s digital solutions in enabling high-quality on-site spare parts manufacturing within portable and containerized environments.
Attendees had the opportunity to witness live LPBF builds monitored by Euler3D’s system, observing firsthand how the digital twin classifies parts into the four acceptance levels immediately after production. Discussions revolved around integrating this framework into existing qualification schemes, standards, and operational procedures within their respective organizations. By grounding these discussions in concrete use cases and real test data, the DISCMAM consortium aims to bridge the gap between abstract promises and practical, adoptable AM solutions for defense.
Broader Implications for Defense Readiness and Sustainability
The DISCMAM project’s success has profound implications for the future of defense logistics and operational readiness. By enabling the on-site production of certified spare parts, it drastically reduces reliance on long, vulnerable supply chains. This not only enhances responsiveness to operational needs but also contributes to greater sustainability by minimizing the transportation of heavy and bulky components.
The digital qualification framework developed by DISCMAM offers a scalable model for other defense organizations and industries facing similar challenges. The ability to trust additively manufactured parts without extensive physical testing is a critical enabler for the widespread adoption of AM in high-stakes environments. This advancement promises to enhance the longevity and operational capability of existing military assets, while also paving the way for more agile and resilient future defense systems. The shift towards digital evidence for qualification represents a paradigm shift, moving from a physically intensive, often delayed, validation process to a rapid, data-driven assurance system that aligns with the demands of modern, dynamic military operations.
