Metalworking fluids play a significant role in machining operations and have a substantial impact on tool life, shop productivity, and the quality of the workpiece. The results presented in this article show the influence of the properties of the metalworking fluids and the supply system on the workpiece quality in cutting and grinding processes. Chemical, physical, and tribological aspects have an impact on the properties of the generated surface. For the assessment of cooling effectiveness, a special test rig for the investigation of the coolant supply system in a grinding process is presented. Another approach to investigate the effectiveness and efficiency of the cooling and lubrication system during grinding is to monitor the temperatures and forces by a wheel-based measurement using telemetric data transmission. A further important aspect of water-soluble metalworking fluids is the influence of microbial effects on working results in machining. Microbial degradation leads to drastic changes in the physical and chemical properties of the metalworking fluid during service life. Besides the demands on the efficiency and economy of cutting processes, their environmental friendliness becomes a crucial issue itself. Therefore, an example for a holistic view on the environmental impacts of machining processes and the application of metalworking fluids is given.

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The chip removal process in grinding is characterized by intensive friction and plastic deformation leading to the risk of thermal damage of the surface-layer of the machined part. Thus productive and reliable grinding processes need effective monitoring. The difficult to access contact zone between the grinding wheel and the workpiece led to extensive research work on the temperature measurement in the grinding arc. In order to develop a tool integrated temperature monitoring system a new approach was undertaken which makes use of the measurement of infrared-radiation to monitor the temperatures in the grinding arc. The presented research work shows promising results suitable for an industrial applicable system for temperature measurement in grinding. The optical transmission of the infrared temperature information in combination with a fast detecting infrared sensor bares the potential to establish a highly miniaturized measuring system which is easy to integrate in any grinding wheel at comparably low production costs.

Grinding processes are often the last step in the value-added chain of high-performance hardened steel components. However, thermo-mechanical loads which can take place during the process can have a detrimental effect on the surface integrity of ground parts, which are generally tested by post-process measurements. In the present study, two different approaches for an in-process inspection of the workpiece surface integrity were assessed using magnetic Barkhausen noise analysis during cylindrical grinding of hardened workpieces. The results showed that both measuring systems are able to detect changes in the surface state of workpieces in-process or directly after grinding in the grinding machine. After preparations to protect the sensors from influences during the grinding process, changes in the residual stress state and a decrease of hardness could be reliably detected. Due to constant contact conditions between sensor and workpiece a high reproducibility of the measurements was achieved.

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In grind-hardening the heat generated by a grinding process is utilized for a surface layer hardening of steel workpieces. In the present work the causes of distortion and its possible compensation were analyzed for single-side and double-sided grind-hardened prismatic workpieces made of 90MnCrV8 (AISI O2). The results show that an increase of the feed speed reduces the resulting martensitic surface layer thickness whereas the influence of the residual tensile stresses on the workpiece distortion increases. Also, shape changes caused in single-side grind-hardening significantly depend on the shape deviations prior to grind-hardening. Moreover, it was not possible to compensate workpiece distortion by a subsequent grind-hardening of opposite sides of the workpiece although the same grinding parameters were used. It is assumed that the stresses state of the clamped workpieces supports the generation of residual tensile stresses and/or reduces the generation of residual compressive stresses in the martensitic surface layer.Beim Schleifhärten wird die während des Spanabtrags mit geometrisch unbestimmter Schneide entstehende Prozesswärme zur Randschichthärtung genutzt. Die hier vorgestellten Arbeiten haben zum Ziel, die Ursachen des durch den Schleifhärteprozesses bedingten Bauteilverzugs und eine mögliche Verzugskompensation beim ein-und doppelseitigen Schleifhärten an Proben aus dem Werkstoff 90MnCrV8 zu untersuchen. Die Ergebnisse zeigen, dass eine Steigerung der tangentialen Vorschubgeschwindigkeit während des Schleifhärtens die Einhärtetiefe bedingt verringert, jedoch die induzierten Zug-Eigenspannugen und den Bauteilverzug erhöht. Des Weiteren zeigte sich, dass der Verzug nach einem einseitigen Schleifhärten signifikant von der Formabweichung der Werkstücke vor dem Schleifhärten beeinflusst wird. Eine Kompensation des Bauteilverzugs durch ein sequentielles Schleifhärten gegenüberliegender Werkstückoberflächen mit identischen Prozessparametern konnte jedoch nicht erreicht werden. Es wird vermutet, dass der Lastspannungszustand durch das Aufspannen der Bauteile in der Werkzeugmaschine die Einbringung von Zug-Eigenspannungen in der martensitisch gehärteten Bauteilrandzone fördert und/oder die Induzierung von Druck-Eigenspannungen behindert.