Retrofitting of plastic injection molding machines in complex production plants (ReKuPa)

Lemgo / Blomberg /

How can rejects from plastic injection moulding machines be minimised or, ideally, completely eliminated? This question arose after a visit to a Digital in NRW LAB tour and subsequent discussions with employees of the Oskar Lehmann company. So-called "misses" are not only an economic problem in the entire plastics industry. In addition to the machine time, energy and resources consumed, these missing parts often have to be disposed of in a time-consuming and thus expensive manner. The more than 500 plastics technology companies in OWL are also engaged in a social discourse about the use of plastics today. They are therefore faced with the conflicting demands of preserving high-quality jobs in the region and using materials and energy responsibly. The avoidance of rejects is thus in the economic focus of the companies as well as in the social focus.

INAsense bei der Arbeit: Das mobile Produktionsdatenerfassungssystem sammelt live-Sensordaten, vom Energieverbrauch über das Maschinenverhalten bis hin zu Umgebungsvariablen.

Applying added value through data

Oskar Lehmann had already realised that the production process depends on many more factors than just the injection moulding machine. These production systems are embedded in halls and are therefore dependent on many more environmental factors than just the machine and material parameters, such as the moisture and material properties of the granulate. For example, draughts in the hall can also have an effect on the injection moulding process and thus also lead to deviations in the component. The experience already gained in the production processes should now be consistently recorded, correlated and systematically analysed with further data.

Retrofitting and machine learning in practice

After the Digital in NRW LAB tour at the SmartfactoryOWL and initial discussions with Mr Gerking (Head of Controlling/IT) and Mr Löhr (Industrial Engineering) from the Oskar Lehman company, the potential was seen that retrofitting and machine learning techniques could be used to implement the existing task. An existing plastic injection moulding machine was equipped with the INASense sensor system in order to record machine data with further process data and to correlate it with data from the quality system. During the recording period, it was also important to integrate the data recording into the production process in real terms and without interruptions. Furthermore, all employees involved in the production process and the works council were informed about the implementation project at an early stage. It turned out that the many years of production experience of the Oskar Lehmann employees ideally complemented the Industrie 4.0 expert knowledge of the Fraunhofer IOSB-INA employees. This was incorporated, for example, in the selection and installation of the additional sensors.

Gain in knowledge for the future in production

After evaluating the results, it was possible to show a correlation between anomalies and certain parameters during the recording period. This made it possible to confirm in a scientific way certain practical assumptions that led to misses in production. These results suggest that longer-term data recording or even permanent integration of further sensor technology into the production system is economically promising. As a further measure, it was recognised that the networking of autonomous "data islands" must be further advanced. Here, too, dedicated training measures are in the pipeline so that Oskar Lehmann employees can drive data integration in production themselves. The visualisation of results in real time via dashboard for all production employees could be another scenario, which is now already being discussed together afterwards with Fa. Oskar Lehmann.


The company Oskar Lehmann GmbH & Co. KG

At the Blomberg-Donop site, Oskar Lehmann produces customised solutions, some of which are products developed in-house for applications in the industrial environment. In the meantime, Oskar Lehmann has more than 40 years of experience in the production of products for a wide range of industries. The customer base includes well-known companies and groups, e.g. from the furniture, automotive, electrical and construction industries. Self-explanatory high quality standards with short development cycles in the delivered products are decisive for a continuous contract production. The continuous increase of core competences is ensured here at the site to a large extent by in-house design and toolmaking. The technical customer advisory service ensures the development and advisory process throughout the entire product life cycle of Oskar Lehmann's customers.

Further information:


Project title: Retrofitting of plastic injection moulding machines in complex production plants (ReKuPa)
Duration: February 2020 until September 2020

Project partners:
Oskar Lehman GmbH & Co. KG
Fraunhofer IOSB-INA
The project in key words:
  • Material- and energy-efficient production
  • Retrofitting of plastic injection moulding machines
  • Anomaly detection in production
  • Concept for data networking and visualisation