GKN Sinter Metals is a developmental partner of the automotive industry producing the widest range of sintered drivetrain components from metal powder worldwide. Powder metal production processes are environmentally friendly, producing safe and quiet-running components with a long service life – the engineers at GKN Sinter Metals see these products as the future trend of gearbox design. GKN's TechCenter at Radevormwald, Germany, is supporting this trend. For many years, the engineers at the TechCenter have been working to optimize manual and automatic gearboxes with universities and renowned research institutions, like the Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University, that specialize in materials science and drivetrain technologies. During the VDI Drivetrain Congress, held from June 24-25 in Friedrichshafen, Germany, GKN will present its product portfolio, field-tested gear developments and technological trends such as lightweight design. Antonio Casellas, vice president of GKN Sinter Metals Global Product Management, said: “Powder metallurgy is a pioneering technology. It offers a variety of process options with specially designed metal powders to meet the increasing demands of the various drivetrain applications. Powder metal offers new possibilities in geometry, such as undercuts, ‘green-in-green’ technology or helical gears to innovate gearbox design.” Four examples of GKN technology include: Conventional compaction Conventional compaction of selected metal powders on GKN developed powder presses using ‘closed-loop’ technology ensures densities above 7.2 g/cc with a homogeneous material structure. The ‘closed-loop’ method developed by GKN allows geometries such as undercuts or the innovative ‘green-in-green’ technology. The surface density is further improved by a subsequent sizing operation. Warm compaction Utilizing warm compaction, a technology developed by GKN, a density of more than 7.35 g/cc is achieved. The powder has been engineered to be compacted in heated tooling. Again, the ‘closed-loop’ process is used. Selective rolling Rolling of selected functional surfaces serves to achieve full density in highly stressed contact areas of the drivetrain component. Helical gears can be provided with a heavy-duty surface area and an elastic core with a supporting strength to optimize application performance. Powder forging Due to its outstanding design flexibility and excellent performance with good geometrical precision, powder forging is an ideal technology for producing drivetrain components because a nearly full density is achieved across the entire volume of the part. In this process, a PM part having a compact density of approximately 7.0 g/cc is fed directly from sintering into a forging press. It is then brought to full density by hot forging. Powder forged synchronizer rings and passenger car connecting rods represent a selection of high volume components that GKN produces for drivetrain applications. An extension to this technology is the development of powder forged gearbox components with helical teeth. The various processes described here represent only a small selection of our technological and economic solutions. These are complemented by our extensive experience in the development of metal powders, powder presses, compaction tooling, sintering and heat treatment for advanced drivetrain applications.