Exciting overtaking maneuver Röhm successfully retrofits giant chuck

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Röhm GmbH

Taiwan Machine Tool & Accessory Builders' Association (TMBA)

Wuxi InfiMotion Technology Co., Ltd.

SIMTOS (Seoul International Machine Tool Show)

Röhm, the clamping and gripping specialist from Sontheim an der Brenz in Baden-Württemberg (Germany), recently impressed with a very special maintenance project...

In this project, Röhm emphasized that everything went smoothly. This referred to the maintenance and refurbishment of a massive chuck with a diameter of 5,500 millimeters. Röhm specialists spent several weeks working in the Sontheim and Dillingen plants and directly at the client's site—one of the leading international manufacturers of large slewing bearings. The Röhm chuck to be maintained consists of over 300 individual parts. After 17 years of continuous use, it was to be restored to its former glory—and, of course, function optimally. The special clamping device is used by the client to process large slewing bearings of various dimensions. These are used as slewing roller or ball connections in construction and vehicle cranes, lifting equipment, mining excavators, tunnel boring machines, or in material handling technology. They also play crucial roles in wind turbines, machine tools, special vehicles, and maritime technology as vital rotating components.

A dozen jaws clamp down quite gently

Installed in 2009, the Röhm chuck is particularly used for processing bearing rings with an outer diameter of up to 6,000 millimeters. Crucial for the user is that over twelve jaws, with a maximum clamping force of 750 kilonewtons, can securely clamp even thin bearing rings and gear rims without deformation—either concentrically or compensatorily. Moreover, due to the quick-release mechanisms on the jaws, the user can rapidly reconfigure for different clamping diameters. The force-introducing components responsible for accuracy were inspected and, as necessary, along with all wear parts, replaced. The aim was to prepare the clamping tool for another 15 years of use. As the Röhm specialists proudly state, the user can now again enjoy a chuck that not only looks like new but also functions as such. The refurbished chuck also boasts a repeatable clamping accuracy of 0.02 millimeters.

For the planned maintenance, the user necessarily had to remove the machine from production. However, they did so with the clear expectation for the Röhm team to keep the interruption as brief as possible. The restart of the machine at the agreed-upon time was also expected to be reliable. Additionally, the maintenance was scheduled to coincide with the maintenance of the machine tool itself. Against this backdrop, the extensive preparatory phase was primarily used to exploit potentials for parallelizing activities and avoiding delays due to unforeseen events, according to Röhm. This was carried out under the motto "Good preparation is everything," and in constant coordination with the customer. For instance, known spare parts were pre-assembled into modules wherever possible to minimize the need for on-site adjustments. The service team benefitted from the special design of the 60-ton chuck, which was originally designed so that the piston and clamping cylinder could be removed without having to dismantle the massive base body. This greatly simplified the maintenance process. The existing overhead crane could be used for the disassembly and reassembly, avoiding the logistical effort and expense of hiring a mobile crane. The disassembly of the chuck then proceeded from the top. First, the clamping cylinders were handled, followed by the pistons, the joint locks, and finally the joint itself.