Manufacturing companies depend on their machinery and are therefore faced with an insoluble dilemma. The stronger the automation and the higher the workload, the more productive the manufacturing process. At the same time, however, automation also increases the susceptibility to errors and reduces flexibility. Plus, high levels of utilization lead to more wear and tear and low reserves in the event of machine failure. It is for this reason that companies often have their own service and maintenance departments, which are able to repair faulty machinery quickly and get it up-and-running again.
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That said, this is of little use if the service employees don’t have access to the spare parts to exchange the faulty ones. On the other hand, keeping spare parts in stock ‘just in case’ ties up capital and takes up storage space. The other dilemma is that, while keeping a large inventory of spare parts allows the company to respond instantly to every fault, it also uses up a lot of money and space. However, if the company keeps a small and therefore inexpensive inventory, it is highly likely that the correct part will not be available in the event of a fault, and that they will have to fall back on expensive express deliveries from the manufacturer.
Optimization of the spare parts strategy requires a two-dimensional approach. On the one hand, it is important to have the right spare parts available in the right quantity - this is where complete service documentation helps, which shows which spare parts are typically required and in which quantity. Drawing on past experience helps companies to find a healthy balance in terms of spare parts storage.
On the other hand, the right service and maintenance strategy can help by enabling you to plan maintenance in such a way that spare parts can be ordered in good time. This avoids faults and, in turn, unexpected repairs. Either way, no modern production facility should still be practicing the lowest level of maintenance strategy, whereby action is only taken once something has broken (reactive maintenance).
The easiest way to avoid malfunctions in the operation of machinery is through preventive maintenance. If you know that the likelihood of a component breaking down increases after a certain duration, you simply replace the part before this limit is reached. This is standard practice with cars – oil change every 25,000 kilometers, timing belt replacement every 120,000 kilometers.
Condition-based maintenance is more sophisticated and more efficient, but it does involve more effort. With this approach, sensors are used to monitor the components that are susceptible to wear, and maintenance is scheduled when certain vibration values, temperatures or other values indicating failure are reached.
Predictive maintenance goes one step further and, rather than relying on fixed threshold values, uses the trend of the measurement data. Each of these methods give the user enough time to order the necessary replacement parts as and when required, rather than having to keep them in stock. The highest level of service and maintenance allows for the optimum coordination of all the maintenance measures with the available maintenance resources.
This approach not only factors in technical considerations but can also incorporate certain economic factors or elements of corporate strategy. This level, which requires a comprehensive information and maintenance infrastructure, is referred to as reliability-centered or financially optimized maintenance.
Any efficient spare parts strategy begins with extensive documentation and evaluation of all the ongoing service and maintenance processes. This allows the company to optimize its capital expenditure for spare parts, while also ensuring the right spare parts are in stock.
The right maintenance strategy can prevent unplanned maintenance, which not only reduces the machinery’s downtime, but also allows for the targeted purchasing of replacement parts as and when required.
Manufacturers can also assist with this, for example – as in the case of car manufacturers – by pooling their findings from many customer machines and providing maintenance specifications. Providing the customer with a simple way to manage their own replacement parts orders, e.g., via an integrated online store, gives them the certainty that they will get the parts quickly, as and when they are needed.
In part 3 of our blog series "From CapEx to OpEx", you will learn how you can reduce your service costs through individualized, easy-to-understand documentation.
