Dual cabin wet blast system for turbine blades
The dual concept guarantees high parts throughput
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By utilizing two stainless steel blast cabinets the wet blast peening system fulfills the customer’s capacity requirements for 14 different types of turbine blades.
Turbine components are exposed to extreme mechanical and thermal loads. To increase residual compressive stresses in their outer surface layers, new as well as parts to be refurbished undergo a shot peening process. Such a custom engineered peening system from Rösler is utilized by a worldwide leader in aerospace technology.
The customer specs called for a maximum cycle time of 10 minutes and an Almen value between N 0.380 and N 0.450 mm and the values of at least 15 sequential Almen readings are only allowed to deviate by 0.02 mm. To meet the capacity requirements of the customer, the shot peening system is equipped with two highly wear resistant stainless steel blast cabinets.
12 blast guns for 14 different turbine blade types
The wet blast system is used for the peening of 14 different types of turbine blades with a maximum length of 1,150 mm. For the peening process the turbine blades are mounted on part specific fixtures and placed on rotating satellite stations. A CNC multi-axis gantry system working with a positional accuracy of 0.1 mm is controlling the movement of the 12 blast guns. The combination of satellite rotation and blast gun movement ensures that the blast media, accelerated by compressed air and consisting of a mix of ceramic beads and water, always hits the parts surface of the curved turbine blades at an optimum angle.
Precise media dosing and intensive monitoring of the peening process
Whenever a turbine blade type change occurs and at the end of each peening cycle a sophisticated rinse system reaching the complete interior of the cabin flushes the thrown blast media from the cabin and transfers it to the media hopper. An auger system below the media hopper transfers the media into the mixing chamber where a wear resistant pump is adding water at a preset quantity. This ensures that an optimum mix of ceramic beads and water is available for the peening process. All parameters affecting the consistency and repeatability of the blast process like, for example, the ratio between blast media and water and the air pressure are continuously monitored and documented in the system controls.
As an all-round supplier, Rösler GmbH is an international market leader in the production of surface finishing, shot blasting machines, painting systems and preservation lines as well as process technology for the rational surface finishing (deburring, descaling, sand removal, polishing, grinding…) of metals and other components. Besides the German plants in Untermerzbach and Bad Staffelstein, the Rösler Group has branches in Great Britain, France, Italy, The Netherlands, Belgium, Austria, Switzerland, Spain, Romania, Russia, China, India, Brazil, South Africa and USA.