Papers by Author: Harald Meier

Abstract: Broaching is an important technique for creating tooth structures in mechanical components. In the present work, the effects of the broaching process on the material state in the near surface region at the root of the tooth was analyzed. The studies were carried out on broached plates made from case hardening steel SAE 5120. The cutting speed and machining condition (cooling lubricant, dry machining) were varied. During broaching with a TiAlN coated tool the cutting forces were monitored. Subsequently, the local residual stresses at the root of the tooth were determined using X-ray diffraction. Further, surface roughness and micro hardness measurements as well as microstructure analysis complement the results. The results indicate that cutting forces have a high influence on the development of the residual stress state at the machined surface whereas no significant effect on changes in surface hardness and microstructure could be observed. Dry cutting with relatively high cutting speeds (≥ 30m/min) result in low cutting forces and hence in high tensile residual stresses in broaching direction.

Abstract: The paper aims to predict component conditions after each subprocess of a manufacturing process chain. A continuous simulation has to be achieved, considering the inheritance of component states. To identify functional descriptions between component conditions as input and output quantities a broaching simulation is being developed. It includes multiple chip formation with multi-toothed broaching tools and machining history of a component as well. For this purpose component conditions are extracted from and transferred to a workpiece model as an initial condition. The 2D finite element chip formation model uses remeshing for material separation allowing highly detailed surface layer characterizations. Parallel experimental studies vary process parameters, whose objective is optimization of process control and forecast of component properties. Characterization of component conditions is based on distortion analysis, cutting force and surface measurements. Comparing the specific cutting forces between simulation model and performed experiments show a reasonable agreement of results