The machine is in exceptionally good condition and was originally part of SKF’s series production line for main shaft bearings used in offshore wind turbines. It was used for the high-precision finishing of the side faces of large-diameter rolling bearings. The machining of these safety-critical components places the highest demands on dimensional accuracy, surface finish, and process reliability

In 2010, the machine underwent a comprehensive mechanical and electrical overhaul. As part of this modernization, the entire automation and drive system was converted to Siemens technology

Grinding Spindle and Table Drive
The main grinding motor (Siemens 1LG6316) delivers 160 kW at 1,490 rpm. A Siemens Sikustart unit ensures smooth starting and gentle braking of the spindle. The rotary table is driven by a 7.5 kW Siemens motor (1LA6), the speed of which is infinitely variable via a Siemens frequency inverter.

Control System and Infeed
Control is handled by a Siemens SIMATIC S7-300 PLC in conjunction with a 4.5-inch operator panel (Siemens OP77B) mounted on the renewed control console. Operational parameters such as speeds, infeed amounts, and dwell times are set via the panel, which also displays diagnostics. Vertical infeed (Z-axis) is driven by a Siemens 1FK7 servomotor (25.6 Nm, 3,000 rpm) combined with a Simodrive 611U control card for precise micro-infeed steps.

Gauging Technology and Control Cabinet
A MARPOSS P7 in-process gauging system integrated via PROFIBUS measures stock removal in real time and automatically stops machining when the target dimension is reached. The control cabinet is divided into power and control sections and equipped with an air conditioning unit. Wiring to moving components is routed in protective metallic conduits. Complete electrical documentation including circuit diagrams and the PLC program is available.