Additive manufacturing: A transformative solution

HOW AM REWIRES REPAIR & INVENTORY MODELS

AM constructs 3D objects layer by layer directly from a digital model (see sidebar “The AM process”). This process represents a way to completely transform how companies manage spare parts and repairs.

The AM process

AM comprises four critical steps that ensure precision, repeatability, and readiness for industrial deployment:

1. Component digitization and analysis. The process begins by capturing the component’s geometry using methods like 3D laser scanning. Next, the team identifies its material composition and critical properties via original documentation review, non-destructive testing, or sample analysis. This combined geometric and material data forms the foundation of a digital twin. In this first phase, it’s important to identify relevant standards (e.g., API [American Petroleum Institute] 20S, API 20T, ISO [International Organisation for Standardization]/ASTM [American Society for Testing and Materials] 52904, DNV ST-B203, Lloyd’s Register, and TWI in the oil & gas sector).
2. Material/process qualification and design optimization. The second step involves selecting an appropriate AM material and process combination that is capable of meeting the original part’s performance specifications. This involves rigorous material qualification and the development/validation of specific process parameters for the chosen printer and material. The component’s geometry is then often redesigned, optimizing it for the selected AM process (e.g., by determining optimal build orientation, minimizing support structures, and accounting for anisotropy) while ensuring functional and performance requirements are met. Simulation tools are frequently used at this stage to predict behavior and validate the design digitally before production. Process repeatability and performance validation of the component are key steps in this phase.
3. Secure digital inventory management. In the third step, all validated build files, process parameters, material specs, simulation results, and qualification data should be stored in a secure digital repository. This digital warehouse must have robust version control, data‐integrity checks, and traceability, replacing (or at least supplementing) physical inventories. As AM adoption grows, so does the need to protect these systems from cyber threats.
4. On-demand distributed production and post-processing. Finally, when a replacement part is needed, the complete, validated data package is sent from the digital warehouse to an approved, certified manufacturing facility (which could be located closer to the point of use). Production occurs on a qualified AM system using the exact predefined parameters. The production step is almost always followed by post-processing steps (e.g., heat treatment, support-structure removal, surface finishing, machining to tolerance, cleaning, and inspection) to ensure it meets required specifications and quality standards before installation.

Reduced lead times & enhanced agility

Traditional spare-part supply management is time-consuming. Lead times range from several weeks (when parts are procured from stock) to many months (for parts that must be manufactured to order). These delays can be exacerbated by supply chain disruptions, such as those caused by a pandemic or geopolitical conflicts.

AM produces parts on demand, significantly reducing lead times. This is critical for industries operating in remote or harsh environments (offshore platforms, remote drilling sites, and even large power plants) and situations where anything more than a few hours of downtime can result in substantial financial losses. In some cases, components that typically take up to 60 weeks to procure through traditional channels can be manufactured using AM in as little as a week. In many cases, parts that are no longer in production due to obsolescence can be fabricated on demand.

ArcelorMittal’s coke plant emergency repair

An ArcelorMittal coke plant in Poland faced a critical challenge when an impeller in the condensation plant needed replacement, and the components were no longer available for purchase. Traditional options included purchasing a new pump or attempting a complex reproduction process. Instead, the maintenance team used AM to produce the replacement part in 316L stainless steel within a few days. The rapid turnaround greatly reduced downtime at a facility responsible for producing more than 4.5 million tons of coke annually (a critical raw material for steel production).

Eliminating expensive excess inventory

A leading US petrochemical firm with 400,000 spare-part SKUs tested on-demand metal AM for a seldom-used industrial blade. Conventional sourcing requires a 10-unit minimum order (~US $990 each), locking up ~$9,900 and significant warehouse space (only one blade is consumed annually). Selective laser melting produced that blade for ~$1,220 plus a one-time ~$977 reverse-engineering fee, cutting first-year cash outlay by ~$7,688. Factoring in 20% annual carrying costs, the print-on-demand model saved the firm ~$658 per blade over a decade while reducing the part’s excess inventory by 90%.

Cost savings & inventory optimization

Organizations across industries face significant costs associated with maintaining large inventories of spare parts that are infrequently used or obsolete. Often, infrequently used spare parts have minimum order requirements, locking up capital and warehouse space. AM lets companies shift from stockpiling to a print-on-demand model, reducing capital requirements and the amount of space needed for parts storage. AM also solves the problem of obsolescence: legacy and/or discontinued components can be scanned or reengineered into digital files and printed on demand.

Design flexibility & part performance

One compelling benefit of AM is the potential for design optimization. Engineers can redesign components to feature improvements like optimized internal geometries, integrated cooling channels, and weight reduction (through lattice structures). These enhancements can lower energy consumption and/or increase the durability of critical components. This design flexibility is especially valuable for parts used in high-pressure, high-temperature, or corrosive environments common to industrial operations.

Alfred Kärcher’s optimized injection-molding line

Alfred Kärcher GmbH, maker of the popular K2 pressure washer, had hit a production ceiling: its plastic-casing molds took too long to cool, limiting output. Renishaw subsidiary LBC Engineering scanned the tooling and identified hot spots caused by straight, drilled cooling channels. Using metal AM, LBC created two replacement mold cores containing curved conformal channels that hugged the part’s shape and extracted heat evenly. The mold-wall temperature fell from 100°C to 70°C, cooling time dropped from 22 s to 10 s, and the full cycle shrank 52 s to 37 s. Kärcher was able to better meet demand without buying extra machines or adding shifts.

AM ADOPTION CHALLENGES

AM’s upsides are substantial, but successful application in the industrial sector requires overcoming technical, operational, and financial challenges.

Technical challenges

• Digitizing and engineering. The majority of industrial assets were designed without the benefit of modern 3D design capabilities. Reverse engineering these parts for AM is often possible, but can be challenging if the original design documentation is incomplete or the part cannot easily be digitized. High-resolution laser, CT scanning, advanced software, and databases can be used to capture precise dimensions, tolerances, and properties of legacy parts (even without the original CAD files), but this requires high-end engineering expertise.
• Material qualification. Industrial equipment often operates under extreme conditions such as high temperature, high pressure, or corrosive environments. Finding materials that can withstand these conditions while preserving the cost-effectiveness of AM can be difficult. For example, traditional alloys and polymers don’t always translate well into AM, and certifying new materials for safety and performance compliance can be a lengthy, resource-intensive process. Access to certain materials can also often be a significant challenge in AM processes.
• Building and post-processing. Stable manufacturing processes and regime management are crucial to the quality and properties of AM parts. This involves equipment calibration, machine/material/process combination alignment, key parameter management (e.g., temperature, atmosphere, oxygen level, energy input), and the addition of special processes (e.g., heat treatment, hot isostatic pressing, machining, surface finishing). This must be done with an eye toward meeting strict industry standards, including for any future use of the part.
• Quality assurance (QA). Traditional machining, injection molding, and casting are well-understood processes. As a new technology, AM products may have flaws not encountered in traditional manufacturing. Defining specific regulation, standards, or conformity requirements suitable for the part (e.g., ASME, API, AMPP/ISO, DNV, ASTM), QA plan/acceptance, and maintaining control over the end-to-end build process using a closed-loop control is essential to ensuring safe use of the part and meeting the operational conditions it is supposed to serve.

Operational challenges

• Safety and compliance challenges. Industrial infrastructure is heavily regulated to ensure safety and environmental protection. The use of AM parts, particularly for high-stakes applications, raises questions about certification, regulatory compliance, and long-term equipment reliability. It may take significant effort (including analysis, documenting, and testing) to confirm that printed parts meet the same thresholds for quality and safety as traditionally manufactured components. High-end engineering capabilities, technically robust processes, strict regulatory compliance, early engagement of regulatory bodies and OEMs, sand-box testing, and physical trials are all essential to reduce safety risks.
• Intellectual property (IP) constraints. AM runs on digital files that include proprietary information. Before printing begins, industrial firms, especially those that depend on a steady flow of replacement parts, must clarify ownership, licensing, and usage rights with the OEM. OEM agreements typically spell out allowable design adaptations, qualified materials and machines, and the warranty conditions that apply when parts are printed outside the OEM’s facilities. To mitigate IP constraints, AM managers should consider starting with parts where IP rights have expired, reducing legal risks. Beyond that, negotiating clear licensing agreements with OEMs is the best way to ensure legal use of proprietary designs.

Financial challenges

• Transition costs. Results from an Arthur D. Little (ADL) project show that for some parts, recurring AM costs are comparable to the manufacturing cost of conventional parts (see Figure 1). However, one-off costs for scanning, designing, and qualification can inflate the total cost, creating an obstacle to AM implementation.
• Running costs. Parts created with AM are likely to remain high compared to traditional manufacturing, but accessibility is on the rise. Industrial-grade metal printers and their post-processing cells, which once carried seven-figure price tags, are becoming more affordable, with competitive pressure and scaled manufacturing pushing equipment costs down by 10%-20% per year. The same is true for many metal powders — as supply availability improves, AM material costs decrease.
• Supply chain adaptation costs. Shifting to on-demand part production using AM requires transforming a company’s internal supply chain processes, including new ways to manage spare parts inventory, new organizing agreements with suppliers, the collocation of printing hubs, and an increase in in-house engineering capabilities. These changes come with investment costs that must be properly captured and evaluated.

Case study — Utility adopts phased AM approach for procurement optimization

A major utility analyzed 700,000 spare-part references to optimize its procurement strategy through AM. After discovering that a large number of parts could be printed using AM, it used a three-phase approach to transition its inventory.

Step 1: Technical feasibility review

A multistage review of the spare-parts pool found that roughly half (the commonly identified candidates, such as complex impellers and small-valve internals) were easily printable using current AM technology (see left side of Figure A). The other half of the pool was moderate-to-low in terms of printability (there were significant technical challenges in the way of using AM to produce them). This comprehensive, systematic review of the parts pool was essential to identify good candidates for printing, including those in less obvious categories.

Step 2: Operational risk mitigation

A phased approach and comprehensive adoption plan were essential for success. The middle of Figure A shows a recategorization of the parts pool based on operational criticality (how critical each part is to continued operations and the risk associated with its failure). The company started by printing low-criticality parts and gradually moved to medium and higher criticality while syncing investments (time and resources) into further studies as a way to align with equipment OEMs.

Step 3: Addressing financial challenges

The right side of Figure A shows the financial feasibility of AM printing spare parts across various criticality categories over time. It indicates that the total cost of AM becomes competitive with (or lower than) traditional manufacturing methods. Although immediate cost benefits may be limited to certain part categories, the technology’s evolving cost-effectiveness (due to gained experience and upgraded equipment) makes it a compelling solution for a broader range of spare parts over time. Of course, keeping an eye on cost and fostering continuous lean improvement are critical to this journey.

Success factors

ADL analysis found that the high expectations surrounding the potential of AM were tempered by significant technical, operational, and financial challenges. Nevertheless, after careful assessment, a viable path forward was identified. The key to success lies in:

• A phased implementation that started with low-criticality parts
• A focus on testing and learning at each stage
• Ongoing efforts to expand the addressable parts pool
• Persistent cost-optimization initiatives (such as reducing one-off costs) to ensure financial viability over time

DUAL-TRACK AM EXCELLENCE FRAMEWORK

To successfully develop an AM-based spare-part program, companies need a holistic strategy that includes both adoption mastery and engineering/AM mastery.

Adoption mastery

AM requires an agile, comprehensive, cross-department adoption program. The first step is a methodical, technically advanced review of the company’s spare-parts portfolio to identify the most viable and high-impact candidates for AM. The next step is creating a phased implementation approach aimed at building confidence and momentum, along with the integration of AM solutions into the organization’s material planning and supply chain management processes. There is also a need to align with both OEMs and regulatory bodies early on to proactively clear IP and compliance hurdles. Finally, adoption mastery involves capturing business value. This includes conducting robust cost-benefit analyses that look beyond the per-part price to include savings from reduced downtime and optimized inventory, as well as establishing clear internal processes to make fast, effective make-or-buy decisions.

Engineering & AM mastery

To succeed with an AM implementation, companies must improve their ability to execute the full process, from engineering (scanning, designing, materials studies, analysis) to manufacturing (build, post-processing, QA). Given the significant investment and specialized nature of AM technologies, creating a sound make-or-buy strategy and leveraging external partners tends to be more efficient than building every capability internally. However, this requires a thoughtful assessment of which capabilities to control internally and which to outsource, as well as a solid managerial framework and a robust assessment of partners to ensure their technical excellence and operational reliability:

• Use internal capabilities and a pool of partners to create a comprehensive suite of capabilities, including advanced scanning and digitization, material science expertise, and a robust engineering backbone to ensure printed parts meet stringent performance requirements.
• Create end-to-end processes for qualifying and testing, secure and reliable digital warehousing, and execution.
• Actively manage costs (its own and those of its partners), including materials sourcing, hardware, and software. Implement continuous development and lean practices as well as a way to leverage economies of scale and experience as the partnership matures.

Interconnected tracks

These two tracks are puzzle pieces that fit together to form a cohesive management system (see Figure 2). Adoption mastery without engineering/AM mastery will lead to well-defined internal needs with no reliable means of execution. Similarly, access to world-class technical partners is of little value if the organization is not operationally prepared to integrate them to identify the right applications. By progressing along these tracks simultaneously, companies can create a virtuous cycle of improvement where organizational adoption fuels engineering excellence (and vice versa).

Conclusion

A METHODICAL APPROACH

Integrating AM into spare-part strategies is more than a technological upgrade — it is a paradigm shift in repair cycles andspare-part inventory management. AM helps companies reduce downtime and lower inventory costs, but implementation requires amethodical approach:

1. Technical constraints associated with spare-parts printing necessitate a thorough analysis of the existing parts pool and an exact end-to-end process.
2. Successful AM requires robust systems to validate the quality and applicability of the parts, as well as a phased approach to technical implementation and organizational change.
3. Operational benefits and cost shifts must be measured and monitored with a clear, consistent plan for driving down OPEX.
4. Implementation requires strong external engineering, AM expertise, and a robust system to manage external technical partners.