By Georg Hübner*
X-ray systems secure the product quality and improve the production sequences at the Bavarian company Privatmolkerei Bechtel.
From a small brook to a large river
The picturesque Naab meanders gently through the Upper Palatinate. It grows from a brook to a river over its course from the source near Weiden to where it flows into the Danube near Regensburg. The Schwarzenfeld-based Privatmolkerei Bechtel has also grown from modest beginnings into a large company in the 110 years of its history. Managing director René Guhl is the head of the family company in the fourth generation. Over one million liters of milk are processed daily at the constantly expanding company headquarters. The main products are yoghurt, liquid milk and cream cheese. Production runs 365 days a year in a fourshift system.
Challenging production process
The processing of raw milk into consumer products consists of complex steps. Products such as quark, hard cheese, drinking milk or butter are produced by means of separators, butter churning machines, milk pasteurizers, filling and packing machines and many more besides. The individual process sequences differ with each end product. The mixture of manual work and the use of machinery is a further challenging feature of the manufacture of milk products.
Hazards are created by material abrasion on the processing machines, wire breakages or the ingress of foreign materials through maintenance work on the building and lants. Even with the greatest of care as at Privatmolkerei Bechtel, safeguards therefore cannot be dispensed with along the way to zero-error production. In addition to the safeguarding performance itself, however, the acquisition of operating data and the complete traceability of these control systems must be possible.
Security with a benefit
“When it came to foreign body inspection it quickly became clear that conventional metal detectors are not suitable for many of our products”, says Dr. Thomas Strixner, who is responsible for the “Quality and Product” business division at the dairy works in the Naab valley. Metallic components are part of the packaging for many products, a typical example being the aluminum seals of yoghurt pots. “After an in-depth consideration of the alternative – industrial X-ray technology – we quickly became aware of further benefits.” Most available X-ray scanners use standardized Industrial PCs with the corresponding operating systems and are thus very simple to integrate into company networks. “A great advantage of this technology was also that even the weighing of the individual products in the bulk packaging was possible with the appropriate algorithms.” Delivery form represents a special problem in the production of yoghurt.
The yoghurt pots are filled and then packed into cartons immediately afterwards. The weighing of the individual products is thus no longer possible. However, an X-ray scanner is capable of visually separating the products and weighing them by meas of density differences. Using classic weighing technology it might not be possible to discover a single underweight yoghurt pot, because several slightly overfilled beakers are possible in a carton. The total weight would then lie within the tolerance despite a single faulty product.
Networked and reliable – the right partner
“The integration of X-ray inspection systems into existing production lines is always a challenge. In this case Mesutronic Gerätebau GmbH offered us the best package for the project planning, the commissioning and the training of personnel”, says Dr. Strixner.
A total of six X-ray inspection systems of the type “easyScope” check various products, including inspecting butter in two-track operation or quark in cartons for contamination with foreign bodies or quality defects. They are integrated into the production data acquisition system as well as the company network. This enables the central acquisition of OEE data on the one hand and the traceable and archive-compliant reporting of performance tests on the other. Apart from that, the manufacturer’s technicians can access the plants for remote maintenance after clearance by Privatmolkerei Bechtel. Karl-Heinz Dürrmeier, managing director of the specialists for foreign body detection from Lower Bavaria, has a clear opinion when it comes to connectivity: “In the era of digitisation and Industry 4.0 it’s no longer enough just to supply a self-contained, good machine. Our systems are networked in a complex production environment and actively contribute to the supply of an errorfree product of the highest quality to the consumer.”
This final goal is shared by both Privatmolkerei Bechtel and Mesutronic Gerätebau GmbH.
* Author is Marketing Manager at MESUTRONIC Gerätebau GmbH