Machining of large workpieces are a matter of scale; The larger the workpiece, the bigger the machining centre. But a lot of time is wasted in transportation to other machines needed for measurement and quality control. Companies aiming to increase productivity are looking for machining centres with integrated measurement systems, while being able to handle large workpieces weighing close to 200 tonnes.
Siemens AG recently commissioned Heinrich Georg for a machining centre capable of complete machining of large, complex workpieces weighing up to 180 tonnes with a diameter of 1,100 mm to 4,000 mm and length of up to 10,000 mm. Called the ultraturn MC, the horizontal machining centre (HMC) combines all machining functions, such as turning, drilling, milling, while incorporating workpiece measuring in one machine.
The HMC is designed for machining of complex, large workpieces, such as forged heavy parts or rolls, turbines, crankshafts and generator rotors as well as compressors or pumps for oil and gas production. The machine offers special characteristics for inside machining of components, such as turn-milling machining or processing of complex inside contours, which are not parallel to the workpiece centre axis.
No Reclamping Required
A new aspect for machining of very large parts is integration of quality control into the production process. Instead of using one probe, the moving two-point automatic workpiece measuring system operates as a big micrometre screw with two probes and measures the workpieces directly in the machine with high precision. While the diameters or axial run-out measuring at workpieces of up to 2,000 mm may take several hours by using measuring machines, the integrated system requires only a few minutes.
The front measuring arm is made of carbon fibre. Thus, it is very light, resistant to vibrations and at the same time stable to temperature fluctuations. The measuring system calibration in the machine is an additional benefit of the integrated measurement. A multi-stage calibration disk is fixed to the tailstock, so that the calibration process can be performed at different diameters.
The largest benefits of having one machining centre carrying out the complete machining and measuring procedure is the simplification of the production planning process. This reduces time on transportation to other machines for measurements, which also means reduced delivery times by weeks or even months. Two more machining centres have been ordered by companies in Eastern Europe and the Czech Republic.
APMEN Metrology & Design, Oct 2016
