The increasing demand for electric vehicles has forced automakers to expand their manufacturing capabilities. It also includes a production line for stator brackets. After casting operations using the Rosler rotary chamber shot blasting machine RWK 6/12-2, the surface refinement of these parts must be achieved in a very short cycle time in an interrelated manufacturing process.

In order to automatically de-sand and deburr different stator supports, the Landshut plant of the BMW Group integrated the swing chamber shot blasting machine RWK 6/12-2 into an interconnected digital production line. Rosler's compact double-chamber shot blasting machine can blast clean aluminum castings in a cycle time of 50 seconds. Through the dual-chamber equipment concept and robotic loading/unloading, non-productive equipment time can be greatly reduced.

Efficient processing, almost no idle time, small footprint In the stator bracket production line, RWK 6/12-2 – including parts feeding system, robot, sandblasting medium discharge station and a small storage area – only 10 Space square meters. RWK can handle the largest diameter carriers up to 1,200 mm in height. 600 mm. The work piece arrives at the conveyor belt from the de-sanding station, where most of the molding sand and core sand have been removed from the casting. The robot is placed in front of the shot blasting machine, picking up one stator bracket at a time, and placing it on a special workpiece fixture in a chamber facing the loading and unloading area. If the workpiece changes, the fixture can be replaced within a few seconds. During the casting process, a data matrix code is inserted into the carrier. To prevent this code from being damaged during the shot peening operation, it is protected by a cover. To this end, Rösler engineers developed a mechanism that automatically moves the protective cover above the code after the carrier is placed on the fixture.

After the loading phase is complete, the chamber rotates 180 degrees. This turn moves the chamber containing the original parts to the blasting area, and moves the chamber containing the finished parts to the loading/unloading area. The robot removes the shot blasted stator bracket, moves it to the media discharge station to shake out the remaining shot blasting media, and then puts it in an intermediate storage location. The best equipment configuration can shorten the cycle time. For this application, the customer uses zinc-cut steel wire for blasting media. The media is accelerated by two Gamma 300G turbines with a drive power of 15 kW and thrown towards the stator bracket. These high-performance turbines developed by Rösler are equipped with Y-design curved blades. Compared with traditional turbines, the accurately calculated blade curvature produces a higher medium throw speed. In turn, this will increase shot peening strength by 20% and significantly reduce energy consumption. High blasting strength, combined with dual-chamber machine design, allows maximum cycle time. 50 seconds.

Another benefit of the gamma turbine is that the special Y design of the throwing blade allows the use of both sides of the blade. This actually doubles their service life. With the quick-change system, the throwing blades can be replaced without removing the turbine from the housing. Due to the workpiece material (aluminum) and shot blasting medium (zinc), the shot blasting machine must be designed with special explosion protection.

This includes special ducts for exhaust air and explosion-proof dust collectors. Digitization improves process stability and operational safety. Through close cooperation with automation experts, Rosler engineers realized part of the digitization of the shot blasting machine.

For example, the complex visualization of the shot blasting operations and shot blasting patterns of two turbines allows the process parameters to be changed during the actual shot blasting process. In addition, the operator can observe which turbine is blasting on which workpiece section in "real time". If necessary, he can initiate changes, reposition the workpiece in the blasting chamber, or modify the blasting time. This may become necessary, for example, if wear of the mold causes more sand to be deposited on a particular part of the workpiece than defined during the initial programming of the shot blasting machine.

The running time is also continuously monitored. After reaching a certain operating hour threshold, the machine automatically provides information about necessary control and maintenance work, such as a protective cover for throwing blades, workpiece fixtures, or matrix codes. This helps to minimize unexpected equipment downtime and significantly increase machine uptime. These aspects are particularly important for the cost-effectiveness of automated production lines. Within the framework of efforts to expand the digitalization of its products, by mid-2021, Rosler will demonstrate further innovative digital development in the field of shot blasting under the brand "Rosler Smart Solutions".

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