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Christmas in a rolling mill – Updating machine safety

Photo | Bosch Rexroth AG
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Photo | Bosch Rexroth AG Magnifier

Everything’s well in hand for the safety-critical controls, too.

Photo | Bosch Rexroth AG Magnifier

What are you doing over the holidays? Engineers at Bosch Rexroth updated the safety level of a rolling mill at Wickeder Westfalenstahl.

A year ago, several service engineers from Bosch Rexroth spent their Christmas holidays in a highly unusual fashion. They organized and coordinated safety technology modernization at a steel rolling mill. In just two weeks.


At the beginning of November 2012, an order landed on the desk at the Factory Automation Service at Bosch Rexroth. A German company, Wickeder Westfalenstahl, wanted to bring the safety technology of its rolling mill up to par with international standards. The scope of the order included: Implementing the safety concept, steering the overall project, realization, and commissioning. In addition, it was necessary to coordinate ten participating companies and supervise the site.

The time frame: 14 days. Start: on December 20, during the company’s Christmas holidays, when the Wickeder machinery would be down in any case. “The first thing I did was to take a deep breath,” explains Johannes Toloczyki, project manager for machine safety at Bosch Rexroth. “We had just received our largest commission as a general contractor in the field of machine safety – and it was supposed to be realized in record time. But after consulting with colleagues and subcontractors we were sure that we could do it. If everybody stepped on the gas.”

Working together against the clock

This contract embraced three separate systems that take 4.5-millimeter steel strip and transform it, solely by hydraulic power, to steel sheet or foil as little as 0.05 millimeters thick. The strip is continuously unwound and rewound beneath the rollers until it is thin enough – and at a velocity of 60 kilometers an hour. The enormous forces and the sharp-edged material racing by here necessitate reliable protection for the operators.

Prior to the decisive realization phase, the machine safety team at Bosch Rexroth worked against time, as the days trickled away, and prepared implementation planning. Toloczyki and his colleagues examined the equipment, prepared schedules and discarded them again, evaluated risks, researched legal mandates and standards, and contacted structural engineering authorities. To make sure on-site workers were kept safe, a first-aid station was set up and, together with external service providers, fire protection was organized at the site. The service people at Bosch Rexroth wrote duty rosters, booked trucks and hotels, lined up tooling. In brief: The responsibility for organization rested solely in the hands of the machine safety team.

There’s no time for dawdling

On December 20, the lights from the Rexroth office container shine into the winter morning at the Wickeder Westfalenstahl plant grounds. The colleagues go through the sequence one last time. It is actually far too early in the day, but no one is yawning. Everyone is working at full blast since the schedule is tight. And finally, things are actually getting started. Beginning now, every action has to mesh with all the others. Up to 55 people are on site and anxious to get started.

Wherever the TÜV technical inspectorate, during its risk analysis, determined that a corresponding safety level was needed, they install monitoring functions. Redundant dual hydraulic systems are mounted, in the interest of safety and reliability. They are equipped with Rexroth valves exhibiting a 150-year mean time between failures.

These specialists fit hydraulic check valves with position monitoring and pressure measurement, integrate emergency stop functions for lifting equipment, and build in safe controls. The men, together with Wickeder, coordinate removing and reinstalling a motor weighing 27 tons. They mount sensors and attend to setting up the switching systems. Turning to the electrical system and automation concept, the Bosch Rexroth specialists program the safety controls – for gates, for example – and connect everything to the rolling mill’s central control room.

The folks in the team from Bosch Rexroth are always right in the middle of things. They answer questions, make decisions, coordinate, keep an eye on the big picture and delve into details, and smoothly shift from one field of technology to another.

A relaxed New Year’s Eve

The operation ends with surprising success. The work is finished on December 31 – two days earlier than planned! Bosch Rexroth submits the documentation and the validation papers based on the Sistema and Eplan software. This makes it easy for Wickeder Westfalenstahl to transfer the entire project into its own database, fully in compliance with standards.