Speed of quality control dictates cycle times for billet shot blast machine
For its customer, Buderus Edelstahl GmbH, Rösler developed the specially engineered billet shot blast system RKL 12-37/300. This machine ensures a throughput of 60 metres/minute (197 ft/min) with a surface quality of SA 2,5 and, compared to other shot blast systems available in the market, it offers significant savings in energy consumption and maintenance costs.
After shot blasting the stainless steel billets with a cross section of 300 x 300 mm (11.8 x 11.8 inches) undergo an ultrasonic test and an inspection for hairline cracks. The cycle time for these quality control checks was the determining factor for the throughput speed of 60 metres/minute (197 ft/min). In addition, after the shot blast process the surface quality of the billets weighing between 750 kg and 5 metric tons and with an initial surface condition of rust grade A or B must be in full compliance with standard SA 2,5. In line with these requirements Rösler developed a custom engineered shot blast system which in all technical aspects was superior to what the competitors offered and perfectly fit into the restricted space at the customer site with numerous pillars and supporting struts.
Two blast chambers – less energy consumption and reduced wear
The shot blast system for Buderus Edelstahl is equipped with two blast chambers operating totally independent from each other. Their housings are made from wear resistant manganese steel, and they are additionally lined with easy to exchange overlapping manganese steel plates. Each blast chamber is equipped with six Rösler Long Life high performance blast turbines mounted vertically in a circular fashion around the chamber housing. The positioning of the turbines, determined by 3D simulation, guarantees an all-around optimum blast cleaning result for all billet sizes. The various blast programs with their operational parameters are stored in the control panel and are selected automatically. The Two-blast-chamber-concept allows the customer to process billets with a cross section of 150 x 150 mm (5.9 inches) – about 70% of the production -- in one blast chamber with six turbines. Larger billets are passing through the second blast chamber which recognizes the larger parts and is automatically switched on. Compared to conventional blast machines which for this application would continuously run with 12 turbines, the Rösler solution not only produces considerably less wear, but it also drastically reduces energy and blast media consumption.
Drive power reduced from 45 to 37 kW – less maintenance – operational cost savings of € 170,000.00 per year
Another technical highlight is the turbines. With conventional turbine types each turbine must have a drive power of 45 kW to successfully handle this blast cleaning application. Because the RKL blast system is equipped with Rösler Long Life high performance Gamma 520 turbines, the installed power per turbine could be reduced to 37 kW. Main reason for the higher efficiency of these unrivaled turbines is the concave shape of the throwing blades allowing a higher throwing speed, respectively a higher blast media throughput. This feature produces either shorter cycle times or significantly lower energy consumption. Since the throwing blades in the Long Life turbines are made from carbide steel, they have a 16 times longer service life, thus drastically reducing the time requirements for maintenance work. The end result: Significantly lower maintenance costs and considerably higher equipment availability.
Rösler GmbH is international market leader in the production of surface finishing, shot blasting machines, painting systems and preservation lines as well as process technology for the rational surface finishing (deburring, descaling, sand removal, polishing, grinding…) of metals and other components. Besides the German plants in Untermerzbach and Bad Staffelstein, the Rösler Group has branches in Great Britain, France, Italy, The Netherlands, Belgium, Austria, Switzerland, Spain, Romania, Russia, China, India, Brazil, South Africa and USA.