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When deep hole drilling problematic aluminum materials, the high ductility and adhesion tendency of these materials lead to the formation of built-up edges, long chips and material adhesions on the tool. This can not only cause rapid tool breakage, but also lead to significant damage to the borehole wall surface. In previous work, it has already been shown that these problems were avoided during vibration-assisted drilling with short tools. Compared to conventional drilling, in vibration-assisted drilling the feed motion is superimposed with a sinusoidal oscillation with a high amplitude and a low frequency resulting in a kinematic cut interruption and the generation of separated chips. The aim of this work is to investigate the extent to which the above mentioned problems encountered in conventional deep hole drilling of aluminum materials can be reduced by vibration-assisted deep hole drilling. To achieve this aim, experiments were carried out in conventional and vibration-assisted deep hole drilling. The chip geometry, feed forces, straightness deviation, surface temperatures and the surface quality of the borehole wall were used as evaluation criteria to compare both processes. It was demonstrated that the formation of built-up edges and material adhesions is avoided by vibration-assisted deep hole drilling. This results in a better surface quality of the borehole wall, what indicates less friction within the borehole due to the generation of small and separated instead of long chips. Since heat generation in vibration-assisted drilling is much lower than in conventional deep hole drilling, boreholes close to the workpiece surface were realized.

Fundamental problems in drilling processes are associated with the unfavorable machining conditions in the tool center and the difficult chip removal. Low frequency vibration assisted drilling (LFVAD), in which the linear tool feed is superimposed with a vibratory motion in feed direction, is a promising process to overcome these problems. Aiming at a systematic analysis of the influence of workpiece material properties, results from LFVAD experiments with Ti6Al4V, AlMgSi0.5 and 42CrMo4 in different heat treatment states are presented. Specifically the dependence of optimal oscillation amplitudes on the workpiece material behavior is analyzed.

Gear hobbing is one of the most common soft-machining processes for pre-toothing. The process kinematics result in a characteristic tooth-flank topography, which is mainly determined by so-called feed marks. For an economical finishing process by gear grinding in automotive applications, the feed-mark depths should not exceed a maximum value of 35 μm. In the present study the validity of this limit has been investigated in view of the development of increasingly powerful grinding machines and grinding wheels. For this purpose, gears with feed-mark depths δx below and above 35 μm were machined and ground by means of discontinuous profile gear grinding afterwards. The influence of the feed marks on the grinding process with roughing parameters was systematically evaluated on the basis of various process variables such as the increase in spindle power Ps or the degree of grinding-wheel clogging Zs, while the resulting gear quality was mainly analyzed by various parameters to describe macro- and micro-geometry deviations of the ground tooth flanks. With increasing feed-mark depth, an increase in spindle power was found due to the additional machined volume. An influence of increasing feed-mark depths on the clogging degree, the grinding-wheel wear and the gear quality could not be proven. Therefore, economical finishing of gears by gear grinding is also possible with feed-mark depths of more than 35 μm. A new definition of this limit should be sought.

By means of surface layer modification charts, the occurrence of thermal impact and thus the risk of grinding burn can be detected. With the present work it was shown that surface layer modification charts for discontinuous profile grinding can be generated using analogy trials carried out on a surface grinding machine for investigation of different grinding conditions and varied tilt angles in profile grinding. The experimental and the analysis effort for the analogy trials prove to be significantly more time and cost saving. The results also suggest that system parameters such as the grinding wheel specification or the cooling strategy are taken into account by the specific grinding power. Thus, the experimental results of this work allow the assumption that the determined process limit is not or just to a low extent depending on the system parameters. This assumption is supported by the thermal process limit determined by Malkin and converted in surface layer modification charts. Malkin's limit, identified for different ground steels with surface and cylindrical grinding processes and thus different system and process parameters, corresponds to the results generated in this work at workpieces ground with a kinematically more complex process. The results reveal that there is at least a group of steel materials which seems to share a similar thermal process limit.

Deep rolling is widely applied to plastically deform specimens. The resulting plastic deformation depends on the process parameters and on the material properties of the deformed parts. As the material properties depend e.g. on the microstructure, within this work deep rolling is used to gain information about the influence of the microstructure on the plastic deformation. Therefore, fast and easily determinable material-specific variables, so called descriptors, are determined. The examination of macro samples with different heat treatments shows an influence of the workpiece hardness and a smaller change due to the different microstructures. Considering equivalent stresses, a process parameter independent analysis was performed. The descriptors determined for macro and additionally processed micro samples showed a progressive trend, which is why a scaling from macro to micro descriptors within the framework of subsequent work is conceivable.