www.hpmag.co.uk HYDRAULICS & PNEUMATICS April/May 2026 31 greatest difficulty are often those that were never intended to be standardised in the first place. Producing these components additively is not a straightforward copy-and-replace exercise. Reverse engineering requires a clear understanding of how the original part performs, particularly where sealing surfaces and pressure boundaries are involved. Hydraulic systems are unforgiving of poor tolerances or surface finish, and any deviation can lead to leakage, pressure loss or contamination issues. Decisions about material choice and post-processing therefore carry as much weight as the initial geometry. In some cases, the design is adjusted to suit the characteristics of the additive process, for example by smoothing internal flow paths or consolidating features that were previously assembled. This introduces an important distinction between simply reproducing a part and improving it. There is an opportunity, when recreating a component, to address known issues such as sharp internal corners that contribute to pressure drop or areas where stress concentrations have led to repeated failure. While the primary aim in a maintenance scenario is to restore function, there is often scope to make incremental improvements without altering the overall behaviour of the system. The way spare parts are managed is also starting to change. Rather than holding extensive physical inventories, some operators are identifying a subset of critical components and ensuring that accurate digital models exist for those items. These models are treated as production data, with defined materials and process parameters, rather than as simple drawings. When a part is required, it can be produced on demand either internally or through a specialist supplier. This approach reduces the need to carry rarely used stock while still providing a route to replacement when needed. For UK operators, the appeal of this model has been reinforced by recent supply chain disruptions. Delays in international shipping and the reduced availability of certain components have highlighted the risks associated with relying entirely on external suppliers. Fluid power systems are particularly exposed because they often depend on a small number of critical parts. Additive manufacturing does not remove that dependency, but it does offer a degree of flexibility by enabling local production where appropriate. Cost considerations Cost considerations tend to be more complex than a simple comparison between manufacturing methods. Additive manufacturing is rarely the lowest-cost option in terms of the part alone, especially when compared with established processes operating at scale. However, maintenance decisions are influenced by the wider cost of downtime, including lost production, contractual penalties and the practical impact on operations. In that context, a more expensive component that restores service quickly may represent the better outcome. Lead time remains a factor that needs to be managed carefully. Even with additive manufacturing, producing a part involves design work, build time and finishing operations. The most effective use of the technology comes when these steps have been considered in advance. Maintenance teams that have identified vulnerable components and prepared digital models are better placed to respond quickly than those attempting to start the process after a failure has occurred. Material performance is another area where caution is required. Hydraulic components in particular are subject to high pressures and cyclic loading, which place demands on strength and fatigue resistance. Additive processes now support a range of metals suitable for many applications, but they do not yet replicate the full range of materials and treatments available through conventional routes. Each application needs to be assessed on its own merits, with appropriate testing and validation where necessary. Quality assurance follows from this. Components produced for use in fluid power systems must meet the same expectations of reliability as those made by traditional methods. Inspection regimes, including dimensional checks and non-destructive testing, are increasingly being applied to additively manufactured parts. The level of scrutiny depends on the function of the component, but pressure-containing parts will always require a higher degree of verification. Not every organisation is in a position to invest in its own additive manufacturing capability, and in many cases that is neither necessary nor desirable. A growing number of specialist providers offer services that cover the full process from design through to production and testing. For many UK companies, this provides access to the technology without the need for significant capital investment, while still allowing them to benefit from shorter lead times and greater flexibility. It is important to recognise that additive manufacturing is not displacing traditional production methods in the context of spare parts. Casting, forging and machining remain the most effective approaches for standard components and for higher volumes. What is changing is the range of options available when those methods are not practical. Additive manufacturing fills a gap that has become more apparent as equipment ages and supply chains evolve. The result is a more adaptable approach to maintenance. Instead of relying solely on what can be sourced externally, engineers have an additional route for addressing failures that would otherwise be difficult to resolve. This does not eliminate the need for planning or for careful engineering judgement, but it does provide a degree of control that was previously lacking. For those responsible for hydraulic and pneumatic systems, the relevance of additive manufacturing lies in its ability to deal with the awkward cases rather than the routine ones. Where parts are standard and readily available, established supply chains continue to serve their purpose. Where they are not, the option to produce a replacement locally, within a controlled framework, is becoming increasingly valuable.
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