Usecase SHB - Highly customized workpieces for crane and hoist equipment
Complete machining without scrap: Highly individualized workpieces for crane and lifting equipment
They are the specialists when it comes to heavy loads. The globally operating company SHB Hebezeugbau GmbH (Saalfeld, Germany) manufactures process cranes with lifting capacities of up to 250 tons for a wide variety of industries such as steel mills and foundries. They also produce special crane systems for the automotive and construction materials industries. Another business area is components for railroad and materials handling technology. For example, disc, and drum brakes for hoists, hydraulic buffer wheel systems, cable drums, or entire winches are developed for customers all over the world and manufactured Made in Germany.
Replacement of several old machines with one turning-milling center
As the demand for components is continuously increasing, SHB has invested in this area and thus in the Saalfeld site: "We have decided to build a new production and storage hall at the Saalfeld site in order to meet the increasing demand for components. In order to optimize the operating processes and increase the production flow at the same time, we have also modernized the machinery. For SHB Hebezeugbau GmbH, it is an investment in the future in order to remain competitive in Germany as a business location," says Managing Partner Thomas Scheffer, explaining the investment. The modernization of the manufacturing facility includes the new acquisition of a turningmilling center from the Chemnitz-based machine tool manufacturer NILES-SIMMONS Industrieanlagen GmbH. This involves replacing several old machines with one new machine. "By using new technologies, a large number of machining operations can be performed on one machine. At the same time, the turning-milling center from NILES-SIMMONS allows us to machine significantly more complex components at a higher quality level and with a greater capacity," says Uwe Dünkel, SHB Hebezeugbau GmbH Plant Manager.
High precision machining of individual rope drums
On the N40MC turning-milling center from NILES-SIMMONS with a nominal length of 4,500 mm and a swing diameter of max. 930 mm, individual, welded rope drums, for instance, are completely machined. By integrating all necessary technologies, such as turning, milling, and drilling into one machine, it is also possible to dispense with the use of various specific individual machines and thus to manufacture more economically in the long term. "Since the individual process steps are automated within one machine, time-consuming parts handling between several machines is eliminated, and the required intermediate storage capacities are reduced. The opportunity for operator error is also significantly reduced, as fewer machines are required overall, meaning fewer operator interventions are necessary throughout the process," says Ralph Mämecke, application engineer at NILES-SIMMONS responsible for the machine, describing the advantage of complete machining. The N40MC is equipped with a milling spindle and a Capto C8 tool interface, a tailstock, and a large steady rest with a clamping range of 250 to 685mm. In addition, a second steady rest of smaller design with a clamping range of 35 to 340mm can be used. The tool magazine contains 48 tools, which are automatically changed via a tool changer. To support the automated machining process, automatic workpiece measuring is integrated into the machine. For this purpose, a probe with radio signal transmission from RENISHAW with a repeat accuracy of 1 µm is used.
The rope drums to be machined are mostly made of unalloyed steels such as S355 J2. Therefore, in addition to standard milling and turning tools, special tools from Sandvik are also used. These are used specifically for the production of the rope grooves. Other operations include the milling of keyways and the insertion of a wide variety of holes. The latter can also be made with threads, e.g. for the rope fastening holes. "The workpieces are mostly welded constructions. In order to maintain this work already done, it is of great importance to always produce good parts and reduce rejects to a minimum. This means that the machined workpiece must always fit exactly at the first attempt. To achieve that, machine and operator must interact optimally," says Mämecke. What is also significant about the workpieces to be produced is that there are hardly any recurring ones. Each rope drum is individual and precisely tailored to the respective crane. Accordingly, the machine processes a variety of changing workpieces in terms of length, diameter, and contours to be manufactured. This requires a highly versatile machine. On the software side, the customer opted for a 5-axis machining package in order to perform B-axis/TRAORI turning. TRAORI turning is an advanced turning process in which simultaneous movement of linear and rotary axes enables dynamic orientation of the tool on the workpiece surface. Furthermore, surface (TRACYL) and face (TRANSMIT) machining are also possible.
The overall concept of the machine proves beneficial
"We decided in favor of a turning-milling center from NILES-SIMMONS because we are convinced of the overall concept of the machine. In advance, we worked out machining strategies for complex components together with NILES-SIMMONS in order to be able to reduce process steps. The result was complete machining for our components. Furthermore, as a German company, we attach great importance to quality “Made in Germany.” Beside the excellent advice, the awesome support from the application engineers, and the very good price-performance ratio, the proximity to the manufacturer is also very pleasant for us. “We did not make the decision easy for ourselves at the beginning. However, after several meetings with NILES-SIMMONS, it became clear that we have comparable values and are “on the same wavelength.” We have confidence and trust in the company and look forward to a long and close partnership," says Uwe Dünkel, SHB Hebezeugbau GmbH Plant Manager