SHL Robotic Grinding System: Reliable Process Eliminates Fire Cracks Focus on surface quality: Johannes Schmidt, Sales Manager of RDW (left) and Heiko Märtens, Sales Manager of SHL. PICTURES: SHL AUTOMATISIERUNGSTECHNIK AG GIESSEREI 102 01/2015 BY MAREIKE KIRCHER, BÖTTINGEN Structural components with some complex geometries t the foundry of Regensburger Druck- gusswerke Wolf (RDW), casting parts with complex geometries is all in a day‘s work. The company produces aluminum components such as housings, transmission covers, and most recently structural com- ponents for many customers and industries. In order to effectively remove fire cracks on the component surface that are caused by wear, RDW depends on the expertise of SHL Automatisierungstechnik AG in the Swabian town of Böttingen. A robotic grinding system from SHL removes the fire cracks with a reliable process. This helps RDW meet the extremely high requirements of its customers, while also saving time and ensuring that the components have a repeatable, precise surface finish. RDW traces its roots to the time when zinc die casting was still a promising technology. Starting in the mid-1970s, the much lighter aluminum took more and more of the mar- ket, and the Upper Palatinate company jum- ped on the bandwagon. Today 95% of the die castings that RDW produces are aluminum, while only 5% are zinc. By the end of the 1980s the company had established an "extended workbench" in Hungary, which started out as a joint venture. After the borders were opened, the Prec-Cast company in the northeast of that country was fully acquired. With over 1.000 of the company‘s 1.400 employees, Hungary is now the largest production location within the corporate group. In addition, a manufacturing plant has been running in China since 2011. The main plant in Regensburg is also the engineering center, focusing on large die- casting cells with 1.300 to 2.800 t of closing force. RDW is 100% family-owned and has an equity ratio of over 67%. The company‘s success has also been due to RDW‘s diverse structure. "Strategically, we concentrate not only on high-volume parts, but on many customers with low volumes", says sales manager Johannes Schmidt. The customer portfolio includes the automotive sector (passenger cars and commercial vehicles) as well as the electrical industry and manu- facturers of agricultural machinery. Today RDW‘s customer list includes well-known automobile manufacturers who purchase struc- tural components with some complex geomet- ries. In this special application, the components are glued to carbon fiber reinforced plastic parts in the customer‘s body assembly process. This requires a homogeneous surface, and a problem occurred in this context. As pressure die casting tools age, small fire cracks appear in the tools. These cause sharp-edged raised areas on the components, which must be clea- ned up in order to obtain a uniform adhesive gap. The question facing RDW was: Should these fire cracks be removed using an awkward and time-consuming manual process, or should the process be automated? Due to the complex part geometries, manual processing with con- ventional grinders was found to be too impre- cise and not reliable enough, based on the to- lerance requirements. After a short discussion, the Regensburg team decided on one hundred percent automated grinding of all adhesive and functional surfaces. To do so, however, RDW needed to find the right partner. "We asked around and performed a classic Internet search. We finally came across SHL and reached out to them," says Schmidt. Initial discussions began in early 2011, and a short time later SHL experts and RDW decision- makers sat down together to look for solutions. "One great challenge was the complexity of the components. They have difficult geometries with many angles and protrusions," says SHL sales manager Heiko Märtens. "We had to find the right machines and especially the tools to be able to handle the required work steps." Extensive testing followed at SHL in close coordination with RDW. The ground finish was coordinated and defined again and again with the automotive customer. "Very intense" is how Johannes Schmidt described relationships with the automation specialists from Böttingen in this phase. They performed extensive tes- ting in their top-of-the-line technology center. Schmidt: "All of the testing was run in-house at SHL before the results were used for the final design and construction of our line." A