Fast Production of Gear Prototypes – A Comparison of Technologies

Abstract

The time-to-market for automotive and other gear-involved products is still reducing. This demands new production technologies for the manufacturing of functional gear prototypes. At the moment gear prototypes are made using classical series production technologies, such as gear hobbing and grinding. However, these technologies require design specific dedicated tools, making the production of a functional gear prototype expensive and time-consuming. This paper presents an experimental investigation and comparison of different alternative production technologies for the manufacturing of functional gear prototypes. Wire-EDM, Selective Laser Melting and milling using standard milling tools, have been compared for the production of a spur gear out of 16MnCr5 steel. A strategy for the wire-cutting of a spur gear was developed, resulting in a total machining time of 22h – with very good gear quality in terms of geometrical accuracy and surface roughness. This same gear has been produced by SLM, with a total machining time of 17h. Two different milling strategies have been developed on a milling machine, resulting in a total machining time of 14h15min. The shape accuracy and surface roughness were compared using a CMM and a surface profiler. Taking these results into account and considering the fact that it is impossible to make helical gears or machine micro flank corrections using wire-EDM, it was concluded that the milling is the most promising production technology for functional gear prototypes. The fact that functional prototypes could be made without the current lead time (± 10 weeks) is a great improvement for the production of gear prototypes, meeting the shorter time-to-market requirements of today's industry.