Fluke Corporation says 83% of UK manufacturers have experienced maintenance delays because required spare parts were unavailable or subject to long lead times, despite businesses already carrying substantial quantities of obsolete inventory.
The research found that one in five UK manufacturers experience parts-related delays regularly, while 68% reported unplanned downtime during the previous 12 months. Respondents estimated that, on average, 22% of the spare-parts inventory held by their organisations is already obsolete.
The UK figures form part of a Censuswide survey commissioned by Fluke covering 600 manufacturing respondents across the UK, Germany, and the US. The sample included food and beverage, oil and gas, life sciences, and automotive businesses, with 199 respondents based in the UK.
The results expose a maintenance problem that is not adequately described as a shortage of stock. A manufacturer can carry significant inventory and still be unable to restore a failed asset if the particular bearing, sensor, drive, control module, seal, or proprietary component required for the repair is missing.
That distinction matters because maintenance inventory is normally accumulated over years rather than designed from scratch. Plants add machinery, modify production lines, replace equipment, inherit spares through acquisitions, and retain components after assets have been decommissioned. Without disciplined links between stores records and the equipment still operating on the factory floor, obsolete stock can continue consuming capital and space long after its maintenance value has disappeared.
Fluke’s research indicates that this mismatch is occurring alongside considerable disruption. Almost a third of UK manufacturers, 31%, identify downtime caused by a lack of serviceable parts or long lead times as a significant cost risk, while 35% point to cross-border shipping and logistics and 32% identify supplier unreliability or geopolitical risk.
Supplier concentration adds another layer. One in five UK respondents single-source critical components or materials within a region, leaving production exposed where an approved supplier experiences capacity problems, transport disruption, material shortages, or a technical failure of its own.
Yet respondents did not identify diversification as an obvious standalone solution. Only 11% selected diversifying or reshoring suppliers as the change most likely to improve their organisation’s resilience, while 14% chose balancing globalisation with reshoring.
That relatively muted response reflects the limitations of adding suppliers without improving the information used to manage them. A second source may reduce dependence on one company, but it can also introduce qualification work, minimum-order quantities, additional specifications, duplicated safety stock, and another set of lead times to monitor.
Paraic O’Lochlainn, vice president of eMaint, a Fluke brand, said: “This isn’t simply a question of how much stock a manufacturer holds.”
The practical issue is therefore asset criticality. A relatively inexpensive component used on a bottleneck machine can justify a higher level of protection than an expensive spare fitted to equipment with built-in redundancy or readily available alternatives. Treating every part according to purchase value alone can direct working capital towards the wrong risks.
Lead time also changes the calculation. A specialist electronic module with a 30-week replacement time may deserve local stock even if it fails rarely, while a commonly available motor or bearing can often be sourced after a fault without materially extending the outage.
Maintenance history provides another source of information. Computerised maintenance management systems can identify recurring failures, consumption rates, emergency purchases, and assets that repeatedly wait for material before repairs can be completed. When those records are connected with procurement and inventory data, manufacturers can distinguish between parts that are merely stored and parts that actually protect production capacity.
The same approach can identify obsolete stock more reliably. A spare should not necessarily be written off simply because the machine for which it was originally bought has been replaced; common components may still support other assets. But stock whose associated equipment, specification, or production process no longer exists needs to be recognised before further purchases compound the problem.
That requires accurate bills of materials and asset records, something older factories do not always possess. Equipment can have decades of modifications behind it, while components installed during repairs may differ from original drawings or manuals. Stores teams can therefore hold parts against an asset description that no longer reflects what maintenance engineers will actually find when the enclosure is opened.
Supply-chain planning and maintenance planning also operate on different timescales. Procurement teams may optimise order quantities and supplier terms annually, whereas maintenance teams encounter failures hour by hour. Connecting the two allows purchasing decisions to reflect the production consequence of a delayed repair rather than simply unit price or inventory-turn targets.
The survey’s 68% unplanned-downtime figure gives that connection a financial dimension. When a critical asset stops, the cost can spread from the maintenance department into lost throughput, labour disruption, missed deliveries, quality problems, overtime, and emergency logistics. A spare part costing a few hundred pounds can therefore carry an operational value far beyond its purchase price.
Buying more of everything is an expensive answer. Carrying additional inventory increases working capital, storage requirements, handling, inspection, and obsolescence exposure, particularly for electronics and proprietary automation hardware whose commercial life may be shorter than that of the machine around it.
Manufacturers instead need a clearer view of which assets matter, which components can stop them, how quickly replacements can be obtained, and whether the stock recorded in the system is both physically available and serviceable.
Fluke’s findings make the contradiction unusually visible: businesses are losing maintenance time waiting for parts while more than a fifth of the inventory already on hand is estimated to be obsolete. Reducing one figure by simply increasing the other would be a rather expensive way to call the problem solved.
