Rubber processing at Kraiburg

Rubber processing at Kraiburg, global rubber processing, hydraulic motors, internal mixers, roll mills
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Tough application

Rubber applications operate in harsh environments and handle heavy loads. There is a risk of injuries to the operators.

Ingenious solution

Active dialog has resulted in unique safety solutions.


“In our experience these are reliable motors that offer a high level of safety. That is why we are installing more and more Hägglunds motors.”

Rubber processing at Kraiburg, global rubber processing, hydraulic motors, internal mixers, roll mills

Kraiburg boosts safety with Hägglunds Drive Systems

The KRAIBURG Group, a leading manufacturer of rubber products, considers occupational safety and reliability top priorities. That’s why Hägglunds products from Bosch Rexroth were chosen when the drive systems for the roll mills in the rubber mixing line were upgraded at the Kraiburg plant.

The manufacturing of products based on rubber compounds and thermoplastic elastomer compounds is extremely challenging. The associates work close to large machines mixing the compounds and forming large workpieces. Machine safety is essential, because of the sheer power needed in the process. KRAIBURG Group, a leading manufacturer of rubber products, relies on Hägglunds hydraulic drive systems, which break wear free.


Unique solution enhances safety

To operate the roll mill, the employees are manually handling the rubber compound as it is being mixed between two steel rollers. “Our employees must feel safe in their work,” says Manfred Achleitner, Technical Manager at Kraiburg Austria. “Hägglunds solutions have several safety-related advantages.” First of all, Hägglunds hydraulic drive systems stop immediately when the safety stop is triggered. The rollers only move less than 10 degrees before they come to a halt, which is vital to prevent serious injury. The company tests the safety stop before every shift. If it reacts too slowly or not at all, the production line cannot start up. But so far this has never been an issue.

“If we were to stop an electromechanical drive as often as we stop these motors, the brakes would wear out too quickly, which would mean more maintenance and repairs. But we can test the Hägglunds motor before every shift, every week of the year. In fact as often as we feel is necessary.” Experts from Rexroth and personnel at Kraiburg have also developed a system that helps to reverse the motor in the event of an emergency stop. “If an accident occurs, it’s crucial to be able to reverse the system slowly and safely. Working with the experts from Bosch Rexroth, we found a suitable solution. Consulting directly with the developers at Rexroth is the key to effective collaboration. Flexible solutions are essential to us.”

Higher productivity

Kraiburg Austria installed its first Hägglunds motor on a roll mill in 1996. Several more followed after that. Seven years ago they also installed a hydraulic drive system in the more demanding 320 liters internal mixer.

“We wanted to improve our manufacturing process,” explains Achleitner. “Since we had such good experience with them in the past, we felt confident installing another hydraulic drive system for our internal mixer.”

The mixing line investment was intended to allow the production of new compounds and to cut costs for existing products. The overall goal was to boost productivity by extending the range of raw materials that could be used.

Since then, other companies in the Kraiburg Group have installed Hägglunds drive systems from Rexroth in their production lines. Werk Waldkraiburg in Germany also chose Hägglunds hydraulic drive systems to replace the company’s existing electromechanical drives. So far, seven Hägglunds drive systems have been installed. Vice President and Technical Plant Manager Klaus Bressel explains:

“Our aim is to cut costs, reduce power consumption and enhance safety. We have an overall focus on cutting energy consumption, and because these systems are designed to produce a lot of power it is always important to find ways of reducing the amount of energy needed, while still getting the same output.”

The hydraulically driven mixing line delivers higher productivity than the previous electromechanical drive systems. One reason is that the four pump units in the Hägglunds drive system start in sequence and without any load; this means that the system requires a lower starting current. In addition, the mixing line can be started and run using only the power that is needed for each particular compound, which leads to better utilization of the complete system.


Constant improvement

When the electromechanical drives are replaced, there is limited space available to install the new motors. Bosch Rexroth works closely with its customers to adapt the motors to their needs.

“We see these machines in operation every day, so we have a good idea of how they can be further improved to suit our needs and where we would like to see more development,” says Achleitner. “We have an ongoing discussion with the developers at Bosch Rexroth regarding safety aspects and ways to reduce energy consumption, and through that dialog we feel that the system is constantly improving while our productivity increases.”

The new mixing line has now been in operation since 2008, and new rubber products have been developed since then, thanks to the unique features of Hägglunds hydraulic drive systems.