Fully automatic shot peening of gear parts for E-vehicles
Shot peening has established itself in the automotive industry as an indispensable surface refinement operation. For this task a leading German automobile manufacturer integrated the indexing satellite table shot blast machine RST 200-S15 from Rösler into a new manufacturing line for gear components for E-vehicles. The customer decided to purchase the Rösler equipment, because he had excellent experience with machines of the same type regarding productivity, process stability and ease of maintenance.
In the automotive industry shot peening is utilized to induce a compressive residual stress in, for example, gear components and, thus, extend the life span of the material. For this challenging task, the BMW plant in Dingolfing uses satellite table shot blast machines from Rösler, which have been precisely adapted to the customer’s technical requirements. Now, the highly adaptable RST 200-S15 equipment concept was implemented in a new manufacturing line producing gear components for E-vehicles.
Designed for high throughput
The rotary table of the compact shot blast machine contains 15 rotating satellite stations equipped with work piece specific fixtures. Depending on the work piece type a work piece loading/unloading system supplied by the customer places one or several work pieces on the satellite stations. Thanks to the clever machine design non-productive idle times are minimal. After they have been loaded, the work pieces are passing through multiple stations in the shot blast machine at indexing cycles of 20 seconds. These stations include two blast positions. Special lifting gates prevent spillage of blast media into other stations. During the peening operation the satellites rotate at preset speeds in front of the blast turbines. In combination with the automatic blast pattern adjustment to the respective work piece shape this ensures that absolutely homogeneous peening results are achieved. A compressed air cleaning station placed in front of the loading/unloading section blows off dust and residual blast media from the finished work pieces.
Selection of the work piece specific processing programs, including the setting of the turbine position and blast pattern, is handled by the master computer of the manufacturing line. For this purpose, the controls of the peening machine were integrated into the upper-level computer system at BMW in Dingolfing.
Energy-efficient blast turbines ensure excellent results
To safely achieve the peening results -- defined by predetermined Almen values -- in the specified cycle times, the machine is equipped with two high-performance blast turbines, model Rutten Gamma 400 with a drive power of 22 kW for each turbine. The special “Y design of the throwing blades with their precisely calculated curvature guarantees a highly precise media acceleration with maximum throwing speed, producing excellent operational efficiency. Compared to conventional turbines this results in lower energy requirements of around 25 %. Another significant benefit of this clever design is that both sides of the throwing blades can be utilized.
To meet the high standards in the automotive industry regarding process stability and traceability of the manufacturing processes, the controls of the shot peening machine allow the continuous monitoring of all relevant shot blasting parameters. This includes the control of the turbine and satellite RPM, the blasting time and the thrown blast media quantity. Replenishment of the blast media also takes place fully automatically.
Other key benefits – wear protection and ease of maintenance
Another key advantage of the Rösler shot peening system is its excellent wear protection, and how easy it can be maintained. The machine housing is made from manganese steel. And the immediate blast area is additionally protected with easily exchangeable protective plates made from highly wear-resistant material. The turbines are made of specially formulated high-strength alloys, which offer a 16 times longer usable life of all major turbine components. Quick and easy accessibility to all maintenance and service points of the shot peening machine are another key feature of the RST 200-S15.The turbines are mounted on doors that can be easily swung out. This facilitates maintenance work on the turbines, for example, turning of the throwing blades, and allows easy access to the blast area for exchanging the protective wear plates. The machine sections for blast media transport and cleaning, as well as the control panel can be easily reached through the large inspection & maintenance platform.