At General Electric Energy Products France, the end to the previous demanding machining of gas turbine components across multiple work steps was marked with a simple "C'est fini". With that, the Group is now shifting the high-precision complete machining of drive elements over to Berthiez RVU 2800/250 grinding machines.
The energy revolution stands and falls with new, efficient gas turbines, which are used in the new clean and efficient gas and steam power plants, for example. There are particularly high requirements on plants for maximum-precision, low-vibration and at the same time highly productive machining of the drive elements. The Berthiez product range of Starrag SAS from Saint Etienne has made a very good name for itself in this aspect of the energy sector, with its large vertical lathes and grinding machines. The factory of GE Energy Products Europe in Bourogne, France, manufacturers gas turbine discs made of steel and Inconel using four Berthiez machine tools whose high-precision machining (concentricity and axial run-out less than 2.0 µm) is not the only are where they are setting standards. A fifth machine will be delivered in 2019.
Post-processing is a thing of the past
"The key objective in purchasing this machine is to bolster our production capabilities," explains Patrick Kaufmann, Project Manager at GE Energy Products. "This is achieved in part by reducing machine cycles and post-processing steps, which means that our quality criteria can be met faster."
The new formula for success is all about complete high-precision processing, and GE's aspirations in this regard are highly specific: "Due to the specific requirements of our products, we're not really in a position to be repeatedly post-processing workpieces across several work steps. We have therefore chosen to shift production to a multifunctional machine. The new machine fulfils all of our processing requirements. The workpiece only needs to be clamped once. Moreover, stringent requirements around precise dimensions are adhered to."
The pieces of equipment in question are the new Berthiez RVU 2800/250 machining centres, which are suitable for grinding, turning, drilling, cutting and performing inline measurements on large components (diameter: max. 2,500 mm; height: up to 1,500 mm) weighing up to 20 t in a single clamping operation. The investment was necessary given the huge changes to production conditions seen since purchasing the first two Berthiez RVM vertical grinding machines in 2002. The size of components is continuously increasing, while tolerances are becoming ever more constricted. "We thus had to find a machine manufacturer who was able to combine durability, processing stability and accuracy," stresses Mr Kaufman. "The situation is further complicated by a specific, changing environment. We therefore need machines that allow us to further refine our products with as little investment expenditure as possible."