Designers’ and manufacturers’ appreciation for aluminum components has been on the rise for several decades, thanks to the lightweighting advantages the material brings, especially in the transportation sector. The more recent growth of hybrid and electric vehicle design and manufacturing has propelled the demand further. EVs take advantage of aluminum’s comparatively low density, which allows significant weight savings in the production of vehicle structures and components – which will expand the operating range of the vehicle battery.
So, the total volume of components produced from aluminum alloys via diecasting (as well as extrusion, and other forming techniques) is rapidly growing.
Diecasting has advantages for designers because it allows them to specify EV parts that are complex, with thin walls. This applies to the housings for different control devices manufactured by Alupress GmbH in Hildburghausen, Germany. There, automaking customers’ growing demand for aluminum diecastings necessitated the investment in a new shot-blast machine that was specially adapted to the strict customer requirements.
Automated all-around solution
The shape and wall thicknesses of the aluminum and magnesium diecastings demanded a shot-blasting process that treats components gently without warping them. At the same time, the shot blasting had to be quick and fully automatic process.
After shot blasting the diecast components pass through a cleaning step and undergo a quality control inspection, before they are packed and shipped. Therefore, besides the shot-blasting machine the project scope also included a transport system that conveys the components automatically through the de-flashing and cleaning stations.
Alupress chose Rösler as its partner for this project having been convinced by the product quality results and productivity of the equipment, as well as the service provided. Another reason was that Rösler had proven its technical competence in processing delicate workpieces in another, similar project. Moreover, for many years Alupress has operated shot-blasting machinery from Rösler, and recognized the quality, productivity, and reliability of this equipment.
Equal force
To ensure gentle but also fast and effective deflashing in continuous flow, the model RHBD 13/18-So continuous feed spinner hanger shot-blast machine is equipped with eight special turbines, each with an installed power of 11 kW. The turbines contain extra wide throwing blades that generate a particularly broad blast pattern.
Furthermore, contrary to the standard placement of the turbines on one side of the blast chamber, the turbines were placed on both sides. This duplex turbine placement, together with the broad blast pattern, generates a gentle blast operation, which significantly minimizes the risk of warping. But the comparatively high throughput for the blast media required for efficient deflashing and cleaning the light metal components ensures a fast and effective shot-blasting operation.
Another feature that prevents workpiece warping is that the workpiece carrier holds 60 to 80 components, and it not only rotates throughout the shot-blasting process but also oscillates back and forth in three positions. This guarantees that flashes and burs are safely removed, even in difficult-to-reach areas like undercuts.
To prevent the blast media – very small aluminum cut wire – from being sucked out of the shot-blast machine by the exhaust air flow and to maintain the required optimum operating mix, the dust collector and the cascade air wash separator were technically modified. The wet dust collector is fully compliant with the ATEX requirements for machinery and workplace safety in the European Union.
Necessary maintenance work is facilitated by multiple connections for cleaning equipment at different sections of the shot-blast machine.
Ergonomic design
A power-and-free handling system ensures easy and trouble-free transport of the workpieces. At the load/unload station the height of the workpiece carrier can be adjusted to the height of the respective operator, thus allowing ergonomic and comfortable working conditions.
Moreover, generously laid-out buffer sections in the transport system permit continuous operation, even during breaks and rest periods. To ensure absolute safety of the personnel, all hazardous areas around the shot-blast machine are equipped with safety mats instead of the usual sensors and enclosures.