Faster cleaning of engine blocks with less personnel

Among other products the renowned Turkish foundry supplies grey and nodular cast iron engine blocks, which are used in commercial vehicles and ships. The raw castings have dimensions of max. 900 x 330 x 140 mm and weigh up to 237 kg. To date, for de-sanding and cleaning the work pieces, the customer, as well as many other foundries, used spinner hanger blast machines. In this particular case the customer used two – one for de-sanding and the other for general cleaning. However, because of a steadily growing production volume the shot blasting operation became increasingly a bottle neck. For this reason, the company decided to purchase an additional, respectively, alternative shot blast system. The customer project team talked with four different equipment manufacturers, one of which was the Rösler Oberflächentechnik GmbH.

A shot blast machine, specially designed for engine blocks
Contrary to the other equipment suppliers, Rösler offered a unique, highly innovative and efficient equipment concept, namely the RMBS 1-6-400-30 engine block blast machine. This blast system, specially adapted to the customer requirements, allows the fully automatic simultaneous blast-cleaning of one large or several smaller engine blocks within short cycle times. Towards this purpose the machine is equipped with a specially engineered gripper-manipulator. After a robot has precisely positioned an engine block in the blast chamber, the gripper picks up and firmly holds this engine block. Once the blast chamber door has been closed, the blast program, tailored to specific work pieces, starts. The gripper precisely rotates the work piece through the blast media stream. To increase the exposure of certain surface areas of the engine block to the blast media, the rotation can be slowed down or interrupted for a pre-defined time period. For simultaneously processing of  several smaller engine blocks, these are mounted to a special work piece fixture. The entire fixture is then picked up by the gripper and rotated through the blast media stream. 

The Rösler solution increases operational efficiency and drastically reduces personnel costs 
With the old spinner hanger blast solution, the work pieces had to be manually loaded onto a special “hanger” before they could be blasted. The new system achieves the required blast results by the targeted movement of the engine blocks through the blast stream. The resulting cycle time savings are such that the de-sanding and surface cleaning operation can now be combined into one single process. This resulted in a significant increase in the overall shot blasting capacity so that the two spinner hanger blast machines used in the past were no longer needed. Moreover, the risk that certain work piece areas are shielded from the blast stream by other work pieces could be completely eliminated. Besides the higher productivity and process reliability, the customer decision for the Rösler system was also influenced by the fact that the new system needs considerably less personnel. In foundries it becomes increasingly difficult to find people for the physically demanding and exhausting work. 

Special wear-resistant foundry version minimizes costs for maintenance 
The desired shot blast results are quickly achieved by the six blast turbines, type Gamma 400G-8 HD, each with an installed drive power of 30 kW. These turbines, specially developed for shot blasting in foundries, are equipped with eight throwing blades in the typical “Y-design as compared to the standard Gamma turbines with six blades. Another major feature of the HD turbine version is that its housing is lined with extremely wear-resistant tool steel. Through this special design the throwing blades achieve an up to three times longer uptime than their standard equivalent. This minimizes work for maintenance and ensures significantly higher productivity and cost-efficiency. The special throwing blade design generates an up to 20 percent higher blast intensity with, at the same time, lower energy consumption. This guarantees a highly effective shot blast operation. Another feature of the Gamma turbines is that both sides of the throwing blades can be used resulting in significant cost savings for spare parts. Blade changes are facilitated by a quick- change system that requires no removal of the turbine from its housing. 
The blast chamber was also designed for high wear resistance. It consists of sturdy manganese steel and is additionally lined with easily replaceable plates made from wear-resistant steel. Areas directly exposed to the blast stream are lined with special cast wear plates.