Zeller+Gmelin lays the foundation for printing ink production 4.0

The company aimed at carrying out all dispensing procedures of liquid raw materials no longer by manual weighing, but by directly using a computer-assisted, fully automated dosing system, which is connected to the in-house ERP-system.

Through automated dosing, Zeller+Gmelin achieves a more precise ink formulation and conserves resources at the same time.

For companies, the responsible handling of raw materials is an important principle both from an ecological and economic point of view. In the Leader’s Declaration of the G7 summit in Elmau in June 2015 concrete efforts were demanded in order to achieve reliable results with the global alliance for resource efficiency. Already in November 2013, the state of Baden-Württemberg had launched an initiative 100 companies for resource efficiency. Zeller+Gmelin had also applied for participation. The focus was on measures that allow for either savings or an improved use of resources in production. The company located in Eislingen was successful with its application, which was based on the introduction of a computerized raw material dosing system.

Automatic dosing of UV-printing inks.

The Division Printing Inks of the company Zeller+Gmelin is specialized in the production of UV-curing printing inks and varnishes for the market segment of packaging and label printing. In the food industry, a continuously growing awareness of consumers and consumer organizations regarding possible migration risks could be observed over the past years. It is feared that components of printing inks could migrate through the packaging material into the food.

Growing demands of consumers and legislator

Today, particularly high requirements must be met when formulating printing inks which are used for food packaging. In addition, an optimization of printing ink formulations is necessary more and more frequently due to new legal requirements. The continuous challenge of adapting the formulations of the inks and varnishes to the requirements necessitates at the same time a need of optimization in the production process.

Dosing plant with control centre.

Modern printing ink production is subject to the obligation to good manufacturing practice according to the European GMP-regulation. Accordingly, the printing ink manufacturer has to define and apply a quality assurance system for all production processes. Specifically, when weighing raw materials – a procedure involving the risk of confusion of raw material and contamination – this system helps to avoid potentially far-reaching effects up to the end user. Furthermore, the quality assurance system offers the possibility to increase the resource efficiency by an improved control of the production processes.

For this reason, Zeller+Gmelin aimed at carrying out all dispensing procedures of liquid raw materials no longer by manual weighing, but by directly using a computer-assisted, fully automated dosing system, which is connected to the in-house ERP-system. By this means, the basis for Industry 4.0 is also provided at Zeller+Gmelin.

The realization of this project is primarily complicated by the very high viscosity of the UV- binding agents. At the same time, these raw materials are very temperature and shear-sensitive, so that an automatic dispensing from storage tanks is extremely difficult. Another challenge is the precise dosing of these high-viscosity components.

Overall concept as solution

To solve this challenging task, a new raw material warehouse with correspondingly tempered storage tanks was designed. In order to keep the transport distances of the liquid components to be dispensed as short as possible, the storage was designed with a direct connection to the dispensing system. Furthermore, it was necessary to find pumps which work particularly low shear and energy-efficient in order to easily pump the binding agents even at relatively high quantities to be dispensed.

Valve series at the new dosing plant.

In close coordination with manufacturers of pumping and dosing systems, various pumping systems and dosing valve systems were tested over a long period of time at a pilot dispensing system. After a test phase of over one year, we developed together with the company Füll Systembau GmbH a concept for a storage and dispensing system including the corresponding and successfully tested pumping systems. In order to actually realize the concept in the end, the construction of a new warehouse and production hall, which was planned and built around the dosing system, was still necessary. In this new building, two storage tank units have been installed and, especially for the high-viscosity products, a heated storage unit has been added in direct vicinity to the dosing unit. This storage unit is heated by means of a heat pump, which is installed in the cooling water circuit and uses waste process heat of the previous production.

The fully automatic dispensing eliminates the error factor human with regard to accuracy, correctness and speed and assures the full reproducibility. Since the introduction, the error rate has fallen to zero errors with regard to false weighing. As a result, the use of resources has also markedly reduced.

In addition, the new system has also optimized the emptying of the packages of high-viscosity resin systems. Hence, the previously required supply in barrels could be converted to larger IBC-containers (Intermediate Bulk Containers), at the same time reducing transport costs and leading to a more effective storage utilization. Moreover, in production we can record an easier handling with improved ergonomic work processes. As an additional side effect, packaging waste has also been reduced.

An important advantage is, above all, the residual emptying of the containers, which has significantly improved by an exact coordination with the dispensing concept. Product residues have been reduced from partially 3 to 5 % to less than 1 %, so that thanks to the almost complete residual emptying only small quantities of residual materials are left to be disposed of and hardly any work equipment has to be cleaned. Accordingly, the amount of waste water contaminated by cleaning processes also drops to a minimum.

Rationalization defuses cost pressure

Altogether, the production processes have been considerably rationalized, so that room for manoeuvre was generated to counter the rising cost pressure. After the conversion from manual to fully automatic weighing (optimum reproducibility), the process department “weighing department” is no longer the bottleneck in the production process and the source of faulty batches which have to be disposed of costly. The throughput has increased considerably, although at the same time it was possible to switch from a 3-shift operation to a 2-shift operation.

The implementation of the new system resulted in a wide range of savings. For example, the raw material loss could be reduced by approx. 8 to 10 tons per year corresponding to raw material savings of approx.40,000 euro to 60,000. Moreover, by eliminating the night shift approximately one third of the energy consumption for electricity, compressed air, gas etc. could be saved. By more compact container units raw material deliveries could be reduced resulting in a decline of CO2-emissions of 20 % in logistics. Finally, it should be noted that the waste heat from the production plants is now being used by means of a heat pump in the cooling water circuit for room air heating and as process heat in the dispensing system.

The implementation of the project has shown where resources can be saved. At the same time, it has provided additional potential for improvement in workplace design, for example by a substantial reduction of lifting and carrying operations. Rationalization effects at various levels have meanwhile improved competitiveness. A further consequence of the automatic dosing concept is an increase in process safety and the compliance with the GMP-requirements. A degree of realisation of 60 % was achieved until 2016. The concept can be extended modularly for future projects and requirements.

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