Sustainable maintenance ensures production efficiency

According to a recent report by Siemens, the cost of production downtime for the 500 companies with the highest turnover has risen from 8% to 11% of their turnover within two years. Higher energy, labor and material costs in the medium term are exacerbating this situation. Moreover, in an environment of material shortages, inflation, economic downturn and all other problems, the outlook for the coming years is not good.

Previously accepted and tolerated downtimes are now becoming a public ‘hidden reserve’ of manufacturing costs. Where plant managers used to be able to argue with an OEE of 75% with conversions, personnel issues and the like, the focus in planning meetings is now increasingly on the missing 25%. Questions about the specific problems and remedial measures and where you will be in three or six months are taking up more space and becoming more concrete.

Nachhaltige Instandhaltung stellt Effizienz der Produktion sicher

Maintenance standards are higher

For many technical managers, this means a paradigm shift – the controllers have learned something new and are also required to drive cost optimization. Of course, downtimes must be differentiated according to logistical (lack of material or personnel) and technical variables, and the sum of technical downtimes is often less than that of logistical downtimes, but falls back all the harder on the technical personnel. While the timely scheduling of materials and personnel is sometimes difficult for purchasing and production management to master for obvious reasons, the demand for maintenance is higher – you have to have your plant under complete control if the other two factors are so difficult to manage.

Awareness and assessment: what is the potential?

From looking at many OEE analyses, it is possible to estimate that a quarter of the OEE gap is due to technical faults. Of course, this is only a starting point; in the example above (75%), 6% of all costs that your plant spends on manufacturing your products would be wasted. To make the calculation more manageable, only the manufacturing costs are included here, not the turnover as stated in the introduction.

This figure is frighteningly high for many plant and maintenance managers, but unfortunately it is still not complete, as all the follow-up costs of technical faults are often not included – from restart costs (such as production release) to worst-case customer complaints. Once Controlling has carried out this calculation, at the latest, it is now a yardstick against which those responsible are measured.

The estimate can now be used to tackle (often familiar) problem areas, albeit from a new perspective for many. The usual technical availability does not say much apart from a percentage, but people start to prick up their ears when concrete costs can be listed.

Determining the costs can be modeled differently

Many different approaches can be used to determine specific downtime costs; however, it is important to ensure that this new key figure is discussed in advance with all those involved in order to ensure understanding and acceptance of this parameter. As this is mainly about inefficient processes (whose ‘owners’ could also be held indirectly responsible for these costs), moderation of this process may need to be considered.

The determination of costs can be modeled in different ways – from pure downtime costs to the inclusion of follow-up costs, such as restart costs and logistical effects. It should be noted here that these effects also go beyond the scope of the actual OEE calculation, as follow-up costs are not taken into account in the OEE system.

Experts tend to look at costs using so-called cost unit accounting, which allocates the manufacturing costs of the products to the respective machines. In the event of a shutdown, the costs can be determined precisely in this way, even if individual production processes are affected. This calculation also includes effects outside of production, for example if administrative costs were calculated via a mark-up on the manufacturing costs and are now no longer covered due to a shutdown.

Planning and transfer to permanent controlling

The downtime costs determined in this way can now be used to plan optimizations. The advantage is that both budget and ROI can be determined at a very early stage, which gives the process a special dynamic.

As described, there is a link between the popular OEE and the manufacturing costs or operating costs of the plant. This can be used to specify failure costs directly – instead of OEE values – to evaluate individual cases of damage more precisely and to achieve much more accurate cost planning overall. The approach can also be used for a risk assessment and its results. The need for stocked spare parts, support contracts with 24/7 coverage or redundant systems can be put on a financial footing.

Sustainable and structured maintenance

In the modern industrial world, it is essential to constantly seek optimization and ensure production efficiency. Sustainable and structured maintenance can be the key to this. Plant and maintenance managers should face up to this challenge and actively work on solutions. Marc Bogenstahl, Director Sales & Business Development Rodias GmbH, on sustainable maintenance: “One of the main aspects of sustainability is the conservation of available and purchasable resources. Transparency, i.e. knowing what I can save and where, plays a very important role here. Otherwise, all optimization efforts will come to nothing. This transparency is also the key to employee motivation. It makes it possible to quantify success, especially the so-called low-hanging fruit.”

“You can associate ‘sustainable’ with ‘intelligent'”

Marc Bogenstahl knows how sustainable maintenance can prevent production downtime or at least reduce the risk of it to a minimum: “Maintenance usually has little potential to be ‘sustainable’ itself compared to production, as the consumption of resources for production is several orders of magnitude greater. It is therefore important to support production with the best possible effort and to optimize its systems with regard to the probability of failure, but also with regard to the consumption of energy, water, materials or lubricants and thus prevent breakdowns.”

The earlier, the more timely and the more professionally maintenance is carried out, the more trouble-free and long-lasting the operation of each system is and the production runs. “To get there, you need to know when these interventions are appropriate and how they should be carried out,” explains Bogenstahl. However, this is knowledge that maintenance first has to build up itself, using the data from maintenance. “You can therefore associate ‘sustainable’ with ‘intelligent’, because perfect maintenance requires a lot of knowledge and a lot of data in order to keep production at an optimal level with its timely and correct use,” concludes Marc Bogenstahl.

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