26.08.2008

Process reliability in a manufacturing network: Timken expands roller bearing capacities with new Schuler Group knuckle-joint press

In order to ensure success on the global market, suppliers are taking on more and more development work from original equipment manufacturers (OEMs). And like OEMs, they are also establishing their own international manufacturing networks. Based in Canton, Ohio, the Timken Company is one of the world’s leading suppliers of bearings. With over 60 production facilities, the company runs one of the largest networks in the part supply industry. Timken expanded its capacities in 2007 with the addition of a new Schuler Group knuckle-joint press for its plant in Sylvania, Georgia.

Plant Manager John R. Kain describes the role of the Sylvania facility for Timken’s global manufacturing network: “Our core competency is the production of roller bearings for trucks. Due to the global increase in demand for these products, we decided to expand the plant’s capacity and to replace the existing press line which we used to produce outer shells for bearings.” John R. Kain goes on to summarize the requirements for Timken’s systems partners: “The main factor in our decision to choose the Schuler Group was quality. As Timken operates a closely coordinated network of manufacturing facilities, our most important decision criteria included not only precision but also production and process reliability.” The decision was also helped by the fact that Timken had already been producing on four Schuler lines at various sites since the mid Nineties and was highly satisfied with their performance.

Turnkey system supplied

Before the new line could set off on its journey across the Atlantic, it had to undergo extensive tests at Gräbener Pressensysteme in Netphen, a subsidiary of the Schuler Group. The main focus was placed on achieving optimum coordination between press and die, as Jan Ebener, Sales Engineer at Gräbener Pressensysteme, explains: “A bearing manufacturer’s know-how is in the die. In order to ensure that the quality achieved during the die’s development also manifests itself in mass manufacturing, we need to coordinate the entire system as accurately as possible with the customer before installation. Only when the line has successfully completed several days of testing is it ready for delivery. We can only call it a turnkey system if the customer literally only has to turn the key to start production.”

However, before staff at Timken’s Sylvania plant could turn the key, Schuler’s specialists still had one more particular challenge to face. As mains supply voltage in Georgia fluctuates much more than in Germany, the main drive had to be suitably adapted. “Globalization always sounds so easy in theory,” comments Jan Ebener. “However, you need the practical experience to make it a success.” The Schuler Group has this experience. After one year in production, Plant Manager John R. Kain is highly satisfied with the press. “The new line meets all our performance requirements. We’ve achieved a significant increase in output and part quality is very good.”

Top quality of complex parts

The new line in Sylvania is based on a mechanical knuckle-joint press from Schuler’s TMK range with a force of 500 metric tons. The modified knuckle-joint drive guarantees high quality and a significant increase in the output of complex parts, such as the bearing shells which Timken produces. As the forming operation itself is relatively slow – and thus gentle on the material – product quality is extremely high. The parts are near-net-shape and can be mounted directly without any subsequent time-consuming finishing. Moreover, the slide movement is much faster during the empty run after bottom dead center than during forming, thus allowing high cycle times in total. The stroking rate of the new press for Timken can be set as required at 20 to 75 strokes per minute.

High output and flexibility

The new Timken press is fully automated. In addition to a coil feeding line with decoiler, threading device, straightening machine, loop equipment and roll feed, the line also features a mechanical ejector system with servo drive and a nine-stage CNC transfer system. With a die mounting area of 3,660 mm by 1,400 mm (width by depth) and the possibility to change tools quickly, Timken can react very flexibly to customer needs and produce a wide range of parts on the press.