November 2024 Volume 6

EQUIPMENT & TECHNOLOGY

THE NEXT LEVEL OF AXIAL FORMING FOR A SUSTAINABLE COMPONENT AND PROCESS CHAIN DESIGN Chipless Manufacturing of Helical Gears Dr.-Ing. N. Missal, Felss Systems GmbH, Königsbach-Stein S. Schwertel, Felss Systems GmbH, Königsbach-Stein M. Ludwig, Felss Systems GmbH, Königsbach-Stein

B ased on the state of the art, the known manufacturing processes for producing external helical gears generally possess specific disadvantages, e.g., high material waste, extremely high tool wear, energy inefficiency, required assembly processes, or insufficient gearing quality. As a result of further development of the Felss core technology – the axial forming process – the mentioned negative effects can be partially or completely avoided. The axial forming process and the new associated machine concept developed as part of a feasibility study allow the manufacture of helical gears with a significant improvement of achievable gear quality to IT5-6 with a total helix deviation of up to 10 µm. Furthermore, the application of an energy and material-efficient cold-forming process, compared to forging or machining processes, offers a significant improvement of the PCF (Product Carbon Footprint) and can provide momentous advantages concerning the sustainability of the automotive industry in series production. Introduction There are over 1.3 billion motor vehicles worldwide today, of which one billion alone are passenger cars. By 2035, this number is expected to rise to around two billion. This enormous increase in the mobility sector poses major challenges not only for Germany, but for almost all industrialized and emerging countries. Traffic- and production related emissions of CO2, air pollutants, and noise are causing prob lems, and dependence on oil imports is growing. Thus, effective climate and environmental protection targets can only be achieved if road traffic and the automotive industry also make a significant contribution. However, because many people still depend on the car, it is not enough to avoid solely on traffic and to focus on short distances and bicycles. Road traffic as well as the production of power-driven vehicles themselves, must become more environmen tally friendly with less negative impact on climate and health, and for a better quality of life in the city of tomorrow. Cold metal forming plays a major role worldwide in the production of vehicle compo nents regarding lightweight construction, sustainability, accuracy, and productivity. By utilizing material and applying a lightweight structural design, cold metal forming can significantly contribute to

reducing the CO2 footprint and emissions of the entire process chain at acceptable costs through innovative solutions [1, 2]. The Felss Group is a globally well-known solution provider in the field of cold forming for the automotive industry. With 100 years of experience in niche technologies, Felss has been able to target rotary swaging and axial forming for the reduction of component weights. As an established lightweight design expert, Felss focuses on identi fying and implementing individual, optimal, sustainable customer oriented solutions and applying them for product development, from the machines to the finished component. Considering the increasing importance of environmental aspects, Felss concentrated its devel opment resources in recent years strongly on generating customer benefits, such as reducing the CO2 footprint. These efforts resulted in entirely new forming processes and the further development of the existing core technologies, rotary swaging, and axial forming. The achieved extension of axial forming process limits, which now enables the production of helical gears, has already been published in [9]. Therefore, the focus of this publication represents the devel opment of the new axial forming machine. State of the Art Axial forming belongs to incremental forming processes, and the principle is shown in Figure 1a. A gear forming tool, e.g., a die, forms the teeth in the axial direction. The gearing is thus highly precise because all teeth are generated simultaneously by a one piece tool directly on the component. Felss axial forming is gener ally carried out by the process of frequency modulation or recursive movement of the forming tool. Thereby, the forming process consists of a continuous repeat of a forward stroke and a subsequent, signifi cantly shorter backward stroke. During the backward stroke, there is no contact between the forming die and the forming zone; thus, the forming zone can be relubricated. Therefore, the typical lubri cation film breakage for the cold metal forming process caused by the high contact stresses and significant surface enlargement can be completely avoided. The frictional forces can thereby be reduced by up to 30% compared to conventional axial forming.

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