Repair and maintenance - responsiveness will remain important in the future!

Reactive maintenance and repair remain important optimisation topics. Run-to-failure may still be the better choice in some cases. However, new technologies can help to increase the first-time-fix rate.

Maintenance and repair remain important.
  • Even in the age of predictive maintenance, unplanned failures and downtime will be on the agenda.
  • AR technology, spare parts management and intelligent capacity management increase responsiveness and help reduce downtime.
  • With the right focus and the application of lean principles, a lot of potential can still be raised in this field.

The discussion about future-oriented maintenance strategies is currently dominated by data-driven approaches in the context of Industry 4.0. If possible, deviations from the target state should be detected at an early stage and unforeseen malfunctions reduced through predictive maintenance approaches. So far, so good. Almost forgotten, however, is the realisation that a resilient maintenance organisation is characterised above all by a rapid restoration of the operating status in the event of a fault.

Corrective maintenance

The quality of reactive maintenance processes has a great influence on the availability of technical systems and is therefore also reflected in the development of classic maintenance indicators such as OEE. However, a complete picture only emerges when maintenance costs are also included in the analysis. This is because the efficiency of corrective measures is reflected in the ratio of input to output. Depending on the objective, the output function can of course vary and the criticality of the performance unit under consideration also plays an important role.

In the area of tension between time, costs and quality, it is therefore important how the maintenance organisation is positioned with regard to the following topics:

  • Responsiveness: Recovery actions can be taken with minimal lead time.
  • Agility: Continuous adaptation and optimisation of repair processes.
  • Efficiency: Every resource expenditure delivers a measurable value contribution.

What skills are important for a repair

In the event of an acute fault, the time factor is decisive. Interruptions in the material flow and associated waiting times increase exponentially in a value chain downstream. Required spare parts should now be in stock and tools at hand. However, it is much more important that technical maintenance personnel are on hand and that everyone involved knows what needs to be done. A fast and effective repair requires that response plans and work instructions are not only prepared for the QM manual, but are continuously developed in the team.

Although the concepts and methods of Total Productive Maintenance (TPM) focus on preventive measures, the basic ideas behind them can be easily transferred. Set-up time optimisation methods, such as SMED (Single Minute Exchange of Die), are also wonderfully suited to constantly improving the First Time Fix Rate (FTFR). With the SMED concept, the analogy of Formula 1 is often used to illustrate the concept. Optimal preparation and a high degree of practice are therefore the recipe for success. Even though no two failures are the same, many things can be standardised and improved. Rare but critical incidents should also be practised regularly, even if there is no safety risk.

When planning maintenance processes, a distinction should therefore also be made between internal and external activities.

  • Internal activities: Can only be carried out when the machine or plant is at a standstill.
  • External activities: Can also be performed when the machine is in operation, shutting down or starting up again.

In many cases, internal activities can also be changed through organisational measures in such a way that they can also take place upstream or downstream. It is equally important for a smooth process that escalation channels and decision-making powers are clearly regulated. Under no circumstances should a lack of authority lead to delays or apparent wrong decisions be sanctioned afterwards.

In summary, good preparation and a modern leadership culture can make all the difference.

Spare parts management

Effective spare parts management remains an essential cornerstone of a functioning maintenance organisation, even in the digital world.

Spare parts management is understood as the optimal stocking of spare parts with regard to costs and availability. Effective spare parts management requires a strategic objective in the form of measurable service levels. For recurring maintenance parts with known consumption, simple consumption-controlled stocking strategies can be used.

  • Small and inexpensive spare parts that are also long-lasting should be stocked on site at the factory. This applies to O-rings, screws, nuts, filters or similar.
  • For cost-intensive parts and assemblies, the delivery speed on the part of the supplier is decisive. The faster, the sooner there is no need for in-house warehousing.

In most cases, however, an individual risk assessment taking into account the failure costs is indispensable.

In many industrial applications, however, functional assemblies are tailored to a specific process. Low quantities and a lack of standardisation make it difficult to keep stock in line with requirements, which represents the optimum balance between safety and economy. In the best case, attention is already paid to this issue during procurement. Often, over the entire life cycle, it can be more cost-effective to purchase a machine that is a little too large in standard design rather than a customised solution that fits exactly.

However, concepts of predictive maintenance or cross-company spare parts pooling could contribute to reducing availability costs in the future. Especially for special components, additive manufacturing processes do not promise a direct increase in the service level, but they are suitable for reducing downtimes.

AR technology enables greater flexibility in capacity planning

A great potential of virtual assistance systems in maintenance is certainly that expert knowledge can be called in via remote support and no longer necessarily has to be on site every shift. This makes it possible to increase the first-time fix rate and save costs at the same time. After initial experiments, more and more companies are taking the step towards augmented reality (AR) to optimise their maintenance processing.

System understanding cannot be replaced

Data-based approaches and predictive models will enable maintenance strategies, fixed intervals will be less crucial. This is not only welcome from a cost perspective, but also much more sustainable. However, the use of new technologies should be done with a clear objective. However, there will still be a large residual area of measures where a reactive run-to-failure strategy is the better choice. Only with a profound understanding of the system can an early assessment be made of where investments really make sense.

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