Maintenance Condition monitoring for autonomous machines

Digitisation is also coming in maintenance. While this topic was once automatically associated with a boiler suit, today digital services and mobile end-devices such as tablets and data glasses are increasingly the norm.

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In a pilot phase, Thyssenkrupp tests intuitively usable mobile end devices which they plan to introduce for both maintenance staff and knowledge managers.
In a pilot phase, Thyssenkrupp tests intuitively usable mobile end devices which they plan to introduce for both maintenance staff and knowledge managers.
(Bild: thyssenkrupp)

The smart factory and the associated digitalisation offer manifold potentials for sustainable predictive maintenance. Yet what advantages accrue from this for firms? And what preconditions have to be created so that data exchange is provided for smoothly running planning, execution and documentation of maintenance?

One thing is certain: maintenance personnel are always the service providers for production – even if the job description has changed drastically in recent years. “Today’s maintenance staff are not only the people who are called when the machine has a mechanical, hydraulic or pneumatic problem. Rather, it is important for a good maintenance person to know both the hardware and software sides of his machines so as to enable good predictive planning of repairs and to obtain necessary materials. Increasingly, help is available here from digital services which support him in monitoring the condition of his machines,” explains Peter Strohm, Project Manager Global Service at the Emag Systems GmbH.

Even at the purchase stage of a machine, firms should make sure that the manufacturer offers service solutions tailored to individual requirements. Emag reacts flexibly on this: “We offer our customers maintenance by our own specialists, but we also support customers who want to take care of this area themselves. Fundamentally, however, it is important that future-security exists for each solution as far as digitisation is concerned,” says Strohm.


The structuring of maintenance

But how should a firm conceive and realise its maintenance processes as sustainably as possible? A new EU standard is available here as a management tool: DIN EN 17007:2017 structures and describes a firm’s typical maintenance processes in a universally valid form. These processes serve as a reference so that, for example, one’s own processes can be matched to those of service providers, or so as to enable comparison with other firms. Going beyond this, these regulations point to suitable parameters for measuring individual maintenance processes. DIN EN 17007:2017 is based on a French standard and was expanded in cooperation with a number of European countries. In Germany, maintenance managers from different firms in manufacturing and processing were involved in developing it. A key role in this was played by Prof. Dr. Lennart Brumby, in charge of the service-engineering curriculum at Baden-Württemberg Dual University in Mannheim.

“In the networked working world of Industry 4.0, it will be important to match to each other not only the data systems, but also the company processes in each situation. Maintenance as a precursor of Industry 4.0 therefore needs reference processes for the essential sequences as well as for the core activities of reactive and corrective maintenance and the multifarious support processes. Only in this way can networking be successful,” he emphasises regarding structuring and compar­able approaches.

“Application of this norm, as with all norms, is not obligatory. But it is surely advisable for each firm to match its own maintenance processes to those outlined in DIN EN 17007:2017. Only in this way will firms be equipped for the world of Industry 4.0,” explains Brumby, commenting on its relevance. Regarding the breadth of their application, he says, “DIN EN 17007:2017 describes not only the classical core maintenance processes, such as repair and preventive maintenance, but also contains the many accompanying supporting processes without which maintenance would not work. And the many links and information flows between these processes are pointed out. It is precisely in the matching and networking of processes that, in the rule, great potential for optimisation lies.”

Predicting failure in axes and spindles

In everyday processes, firms can take very practical orientation from the new norm. “At Emag, we have been working for some time on a product which enables analysis of wear in the axes and spindles of machines by means of vibration sensors. In a defined dry run with the machine, we will in future work out, with the help of an algorithm, which components in the machine will fail in the near future, thus providing optimal support for the maintenance worker in planning repairs and service,” says expert Peter Strohm, giving an example. The aim of this preventive and predictive maintenance is to eliminate downtimes completely in future. In practice, the Emag system has already proved itself, for at this moment it is running successfully in test operations with pilot customers.

A further example is a service app from Emag. “This makes it easy for a maintenance worker to contact our service. By scanning a QR code on a new Emag machine, the app recognises the machine type and location and can select the right service dialogue partner. Old machines will be retrofitted regardless of age,” explains Strohm. Optionally, customers can then contact the specialists by telephone, e-mail or live videochat.

Firms must train their workers

Comprehensive know-how; regarding the analysis of the large quantities of sensor and production data; has strategic importance for Emag. Against this background, last September the Emag Group took out a minority interest in the firm Anacision, a data analysis specialist based in Karlsruhe. The partners now jointly develop software solutions for machine construction – in the field of predictive maintenance, for example. “We consider our minority interest in Anacision to be the start signal for a far-ranging strategic development partnership in the Industry 4.0 field,” says Markus Heßbrüggen, CEO of the Emag Group.

Data security for all involved

But today’s specialists must not only optimise and maintain machines and automation systems. They must also ensure that the systems communicate with each other. In addition, data analysis must be possible via all interfaces involved. The ultimate aim is to identify further potential for efficiency and to respond with suit­able measures. In particular, the interface between IT and maintenance is an important cornerstone of modern maintenance.

“Here lies a major challenge for firms, for in this complex environment they must create suitable qualifications for staff,” says Dr. Jens Reichel, in charge of technical services and energy at the Thyssenkrupp Steel Europe AG in Duisburg. Since IT specialists are in great demand on the labour market, this can sometimes be very difficult for the firms.

According to Reichel, a further important topic in digitised mobile maintenance is data security. Nowadays, smart services are often implemented in such a way that production firms feed a cloud with production data via an interface. In the cloud, the relevant analyses are carried out in the background, and these in turn enable conclusions to be drawn regarding not only events in the installation, but also the likelihood of outages.

“Many manufacturing firms are reluctant to let third parties see into their data: first of all because it may reveal process parameters and thus give away in-house know-how, and secondly it opens up access to production operations which can be misused,” Reichel says from experience.

To counteract this, very robust filters are created for these open channels, so-called firewalls. With their help, firms make it much more difficult for the intruder. A second way is to carefully limit the opening of data to only what is necessary for the task in question. This means that the available data is filtered in advance to reduce it precisely to the quantity needed for the planned analysis.

In this case, staff have to be sensitised regarding the necessary security procedures to be installed in the relevant interfaces.

“In the end, the important thing is to realise that, in maintenance, I find myself in an area containing valuable firm know-how which has to be protected,” emphasises Reichel on this important topic.

Precisely tailored condition monitoring

The machine builder Emag guarantees data and access security by placing an intervening evaluation PC in the machine control system to assess requests for defying data. “The PC places the data on a local server on the customer’s premises. The customer can then decide whether, and which, data should be synchronised with a cloud server. As a result, the machine control system is not connected directly to the internet and the customer has a free choice in how he handles his data,” project manager Peter Strohm explains.

Yet maintenance also offers additional potential for efficiency in some areas. At Thyssenkrupp Steel, experts are currently consulting on how condition monitoring systems can be developed towards being coupled with data from process management, process automation systems and quality management.

“The aim is to make deductions from the data regarding the optimum running of the installation, that is, optimised either for service life or, depending on the spectrum of parts, for the highest possible throughput, or for the best possible quality,” Reichel elucidates.

This much is clear: maintenance today is a very complex topic which offers numerous potentials for improved efficiency, but it brings with it many challenges. This is addressed in the new DIN EN 17007:2017, which gives practical orientational help. Brumby underlines this: “Never before has there been such a comprehensive description of maintenance processes. Earlier descriptions have always portrayed only partial aspects of maintenance. The networking of processes, which is where the real complexity of maintenance lies, is sometimes left out of the picture.”

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* Dipl. Eng. Annedore Bose-Munde is a specialist author in 99094 Erfurt, tel. (03 61) 78 94 46 95,,