Ready for production on time once again: Röhm specialists overhaul large chuck

Once again, Röhm's service ran like clockwork: The clamping and gripping equipment specialist from Sontheim an der Brenz (Baden-Württemberg) has now impressed with a very unusual maintenance project – the reconditioning of a huge chuck with an external diameter of 5,500 mm. The Röhm specialists spent several weeks at the Sontheim and Dillingen plants and directly at the customer's premises, one of the leading international manufacturers of slewing bearings, to refurbish a Röhm chuck consisting of over 300 individual parts after 17 years of uninterrupted use. The special clamping device is used to machine slewing bearings of various dimensions at the user's premises. These are used as roller slewing rings or ball slewing rings in construction and mobile cranes, hoists, mining excavators, tunnel boring machines or in handling technology systems, among others. Slewing bearings are also important slewing components in wind turbines, machine tools, special vehicles and maritime technology.

12 clamping jaws for workpieces up to 5,500 mm in size

The Röhm chuck installed in 2009 is used in particular to machine bearing rings with an outer diameter of up to 6,000 mm. Crucial for the user: Using twelve clamping jaws with a maximum clamping force of 750 kN, even thin bearing rings and gear rims can be clamped with absolutely minimal deformation – centrically or compensating. In addition, the customer can quickly change over to different clamping diameters thanks to the quick-release fasteners on the clamping jaws.

Like new

“The components that apply force and are responsible for accuracy were inspected and replaced, if necessary, as were all wear parts – with the aim of making the clamping device fit for another 15 years. Our customer can now look forward to a chuck that not only looks like new, but also works like a new one,” says Dr. Christoph Schaich, Head of the Service Department at Röhm GmbH. The reconditioned chuck has a repeat clamping accuracy of 0.02 mm.

Base body can remain on the machine

For the planned maintenance, the customer had to take the machine out of production – with the clear expectation that the Röhm team would keep the interruption as short as possible and ensure a reliable restart on the agreed date. In addition, the maintenance was to take place at the same time as the machine tool maintenance.

With this in mind, the extensive preparation phase was used above all to exploit the potential for parallelizing activities and avoiding delays due to unforeseen circumstances – according to the motto “Good preparation is everything” and in constant coordination with the customer. For example, spare parts that were known in advance were pre-assembled into modules wherever possible in order to minimize the need for on-site adjustments.

At the customer's site, the service team was helped by the special design of the 60-ton chuck: At the time, this was specially designed so that the piston and clamping cylinder could be removed without dismantling the huge base body. “This simplifies the maintenance process enormously, as we were able to use the existing overhead crane for disassembly and reassembly, saving our customer the additional costs and organizational effort of a mobile crane,” says Sven Grüner, the on-site assembly manager. The chuck was therefore dismantled from the top. First came the clamping cylinders, then the pistons, the joint lock and finally the joint.

Chuck optimized

On the cylinder, the Röhm specialists cleaned the distributor shaft and the pistons, then on the chuck, they cleaned the pistons, the pendulum pins, pendulum bridges, centering ring, bearing pins, driver, joint lock, angle lever and the U-piece. “In this context, we also made one or two small changes to the chuck to make it more user-friendly. Where possible, we reinstalled the old parts after reconditioning,” explains Grüner.

At times, work on chuck components was carried out simultaneously on-site and in the factory in order to keep to the demanding schedule and to immediately implement work that could only be determined after the chuck had been opened.

All tests passed

As part of the reconditioning process, all parts and components underwent the relevant tests before and after assembly. After assembly, the centering accuracy and pendulum compensation for blanks and round workpieces as well as the repeat clamping accuracy with centric clamping were checked. Before shipment to the customer, the pistons also had to be put on the Röhm test bench to test the pneumatic and hydraulic tightness. The test for the tightness of the central lubrication system took 24 hours.

“Our customer and we are very satisfied with the progress of this exceptionally complex project. The requirement was that the maintenance and repair of the chuck should not take longer than the maintenance of the machine. We complied with this. The preparatory work at our factory in Sontheim took one week, after which we were on-site at the customer's premises for three weeks with a three-man team,” explains Schaich.

Impressive after sales service

For Röhm CEO Gerhard Glanz, the maintenance project is a prime example of the quality of service at Röhm. “We are not only a manufacturer of clamping, gripping and handling technology, but also a strong service provider. When a chuck is running like new again after 17 years, it shows impressively that we are the solution provider par excellence for our customers. That's what I call after-sales service in the XXL version. I can only congratulate our team”.

Röhm offers its customers the following services: repair service for catalog items, on-site clamping force measurement with test certificate, repair service for special clamping devices, commissioning and start-up support, preventive maintenance, spare parts and maintenance kits as well as a retrofit for the smart clamping jaw iJaw with clamping force measurement in real-time.

About Röhm GmbH:

Röhm GmbH, headquartered in Sontheim an der Brenz (Baden-Württemberg, Germany) and with production sites in Dillingen (Bavaria) and St. Georgen (Black Forest), specializes in the development, design and manufacturing of highly precise, robust clamping and gripping devices with long service lives. Our products are “Made in Germany”. Almost all top manufacturers in the global automotive, railroad technology, watchmaking, medical technology, energy technology, and woodworking industries use Röhm clamping and gripping devices. Röhm also produces special clamping devices and handling systems for use in clean rooms that comply with clean room class ISO 7 requirements. 

Röhm has fully owned subsidiaries in France, Italy, Switzerland, Spain, Poland, the UK, the USA, China, and Mexico. The company, founded in 1909, quickly gained a global reputation for its drill chucks. To this day, Röhm still develops and manufactures drill chucks at its Sontheim site that almost all manufacturers worldwide use on stationary and hand-guided electric tools for screwing and drilling applications. 

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