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Achieving Smooth Shot Blasting Of Bulk Workpieces
When it comes to developing and manufacturing automotive components for lowering weights and reducing CO2 emissions, the worldwide active Mubea group is without any doubt one of the global leaders. The company’s products include components for automotive chassis, car bodies, and drivetrains.
Besides serving the automotive industry, the Mubea group also manufactures components and assemblies for aerospace and home appliances and offers custom-engineered solutions for other industrial applications.
With over 700 different types Mubea also markets the worldwide largest range of spring band clips, generally known as hose clamps. More than one billion of these hose/pipe union connection elements are produced at locations in Europe, Asia, and North & South America.
Simulation Helps Reduce the Cycle Time for Peening of Spring Band Clips
To make these components, manufactured from high-strength alloyed tool steel, more resistant against the constantly changing loads in vehicles, their tensile strength is improved by shot peening them.
For this purpose the Mubea Automotive Poland sp. zo.o. purchased a second Rösler shot blast machine. The Multi-Tumbler RMT 70 allows the fully automatic shot peening of spring band clips in batches weighing up to 1,800 kg.
A key factor in the customer’s decision for this machine type was the geometry of the blast barrel. A simulation of the workpiece behavior in the blast barrel provided valuable design pointers making sure that the workpieces are perfectly mixed. This helped to shorten the actual peening time.
The unique barrel design also helped prevent any rejects by workpieces getting stuck and, thus, helped improve the overall productivity.
High-cost Efficiency and Reduced Requirements for Maintenance
To comply with the strict specifications of Mubea Automotive Poland, the Multi-Tumbler is fitted with a Long Life Rutten blast turbine with curved throwing blades in “Y” shape and installed power of 30 kiloWatts. The precise curvature of the blades generates an extremely high throwing speed along with precise media guidance resulting in an optimal blasting efficiency.
At the same time, the turbine requires a lot less energy, reducing the energy consumption by up to 25%. The throwing blades are made from a highly wear-resistant alloy, and their special “Y” design allows using both blade sides.
For this reason—depending on the blast media used—the Rutten high-performance turbines achieve a 10 to 16 times higher uptime compared to conventional blast turbines. This results in a significant increase in equipment availability and drastically lower costs for maintenance.
An Automation Concept That Is Precisely Tuned to the Customer’s Requirements
To completely automate the shot peening process, the shot blast machine was equipped with a special workpiece loading system that includes a weighing cell and the required software integration. This allows calculating the optimum batch weight during the automatic workpiece load operation.
The PLC adapts the shot peening time to the actual weight of the respective workpiece batch. Throughout the peening operation, the barrel is completely sealed with a lid. The barrel and turbine RPM are automatically adjusted with frequency inverters.
All these features, combined with the optimum mixing of the workpieces in the barrel, make sure that absolutely consistent, repeatable peening results are achieved in surprisingly short cycle times. Of course, the continuous monitoring of all critical process parameters also contributes to process safety and stability.
The blast media recycling and cleaning system is adapted to the overall system and guarantees the consistently high blast media quality required for the shot peening process.
