**4. Conclusions**

This paper presents the investigation of the application of a feeling machine for process monitoring. In order to replace the dynamometer, a feeling turret was used, which determines process forces based on the structure's integrated strain gauges. The monitoring quality was compared with the performance of a dynamometer regarding the detection of tool breakage, tool wear, and material transitions of hybrid components. Investigations have shown that, especially in roughing operations, which are characterized by higher process forces, the feeling turret has a good monitoring performance. At depths of cut of *ap* = 1 mm, similar sensitivities were determined for monitoring with confidence limits as with a dynamometer. If steel is machined, tool wear can be detected with the cutting force of the feeling turret for roughing and finishing processes. For aluminum, on the other hand, only monitoring roughing processes can be realized. However, it must be assumed that the tool wear also leads to a significant change in cutting force of 10–30%. Similar to the dynamometer, the feeling turret is suitable for monitoring the materials of aluminium-steel compound (EN AW-6082/20MnCr5). For the examined process parameter range, the statistical overlap factor was higher than six. Consequently, a classification of the materials based on the material-specific cutting force can be achieved. In further steps, it will be investigated how the fusion of signals from the feeling machine and process data from the machine control and external sensors can be used to improve the monitoring quality.

**Author Contributions:** Conceptualization, M.W. and B.B.; funding acquisition, B.D. and B.B.; investigation, M.W.; methodology, M.W. and B.B.; supervision, B.D.; validation, B.B.; writing—original draft, M.W.; writing—review & editing, B.D. and B.B. All authors have read and agreed to the published version of the manuscript.

**Funding:** The results presented in this paper were obtained within the Collaborative Research Centre 1153 "Process chain to produce hybrid high performance components by Tailored Forming" in the subproject B5 (252662854). The authors would like to thank the German Research Foundation (DFG) for its financial and organisational support of this project.

**Conflicts of Interest:** The authors declare no conflict of interest.
