At UWS Rothenseer Guss- und Metallbearbeitungs GmbH the growing size and weight of the castings handled by this company required the investment in a new shot blast machine. This job shop company decided for the fully automatic spinner hanger shot blast system RHBE 40/30 from Rösler.
Since 2001 the UWS Rothenseer Guss- und Metallbearbeitungs GmbH, located in Magdeburg, Germany, has specialized in job shop work for castings. Its services cover a wide range of activities: From fettling, separation, welding, painting of the components, all the way up to non-destructive material testing. Until recently the large castings were shot blasted manually requiring a lot of time and labor. Since the share of large and heavy castings, such as the rotor hub of wind power stations, has been increasing significantly, the company had to invest in a new shot blast system. Says Norbert Slobodan, one of the USW managers: “A major factor in our decision for the Rösler equipment was the good reference from another customer who operates a similar Rösler machine. But also very important for us was to go with a supplier who offers reliable and quick service. In addition, the machine had to be fitted into a room with a relatively low ceiling height.”
A sturdy design with focus on easy maintenance
Based on the RHBE 40/50 the engineers from the company in Untermerzbach developed an equipment concept that met all the customer’s requirements. For example, because of the low ceiling height the machine is equipped with a split elevator. Other customer specific characteristics are the relatively small foundation pit and the placement of the machine on floor level. This allows the operator unimpeded access to the blast chamber.
The RHBE is designed for single piece or batch operation for parts with a diameter of maximum 4,000 mm (160 inches), a height of 3,000 mm (120 inches) and a total weight of 15 metric tons (33,000 lbs). An integrated mono rail crane is utilized to place the parts in the blast chamber. Various parts-specific programs are stored in the PLC for blast cleaning the various castings contaminated with sand and scale. “We achieve excellent blast cleaning results for all our parts”, explains Norbert Swoboda. A short cycle time compared to the previous blasting process is achieved with four (4) single disk blast turbines, model H 42, with a power of 22 kW each. Of course, this high blast intensity required a special wear resistant design of the blast chamber made from manganese steel. In addition, all critical areas in the blast chamber are lined with easy to replace, 12 mm thick plates made from especially wear resistant material.
Blast media recycling and cleaning – tailor made for foundry applications
Blast media that falls to the floor, when the finished parts are transported from the blast chamber and unloaded, can easily be swept back into the blast chamber with a broom. For the blast media return Rösler is not using an auger but a vibratory conveyor which discharges coarse particles, before the blast media reaches the elevator. For the separation of the blast media from the large amounts of sand the spinner hanger shot blast machine is equipped with a highly effective dual drum magnetic separator. The mix of media and sand is guided as a thin curtain between two extra wide magnetic drums. The high magnetic force of the permanent magnets placed inside the drums separates the ferritic blast media from the sand with an astonishing efficiency of 99 percent. Because of the high abrasivity of the sand a sintered and ribbed dust collector was installed which compared to standard dust collectors offers an up to 10 times higher uptime.
UWS was also impressed by the maintenance friendly design of the RHBE. All areas of the shot blast machine requiring regular service can be easily reached by the maintenance personnel. Explains Mr. Swoboda: “The life of the wear parts is very good, and we receive our spare parts promptly. Because of the easy access to all critical service areas we can replace the spare parts within a very short time period”. This is a major factor for the high availability (uptime) and cost efficiency of the Rösler shot blast system.