Wear Prediction for Oscillating Gear Forming Processes Using Numerical Methods

Abstract:

Oscillating forming processes offer outstanding opportunities for lightweight applications and economic advantages. Gears, especially splines, are industrially produced by oscillating ram movements. The oscillations enable the precise manufacturing of the gearing on the tubes. At the same time, they also enlarge the sliding distance in each stroke. Therefore, tool wear has to be considered carefully. Observations of oscillating gear forming processes reveal a startling phenomenon: Calibration regions of tools show the first wear marks during the manufacturing process, although the maximum contact stress is located in the forming area. According to Archard’s equation, the maximum wear is expected to be located in the area of maximum contact normal stress. In this paper wear prediction based on numerical simulations and a modified Archard ́s equation is presented. The implemented wear factor is of particular influence. Adequate values for this factor are derived from gear forming processes with tools made out of the steel 1.2379. Splines made of case hardening steel (16MnCrS5) can be produced with these tools, but wear is already evolving when laboratory lots are produced. Wear behavior and wear volume are recorded and used to determine the wear factor. The resulting values for wear factors in Archard’s equation indicate that changing contact and lubrication conditions during the pre-and the backstroke of oscillating processes have to be taken into account in wear modelling. This is achieved by a decomposition of the wear index into material and lubrication related factors. The extended model allows for a local wear forecast in processes with oscillating ram movements for which Archard’s classic wear model does not give plausible results.

• Periodical: Key Engineering Materials (Volume 767)
• Pages: 283-289
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.767.283
• Online since: April 2018
• Authors: Wilhelm Schmidt*, Peter Groche
• Keywords: Archard, Cold Forging, Oscillating Gear Forming, Spline, Tribology, Wear

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