GRINDING WHEEL MONITORING SYSTEM

It has been hypothesized that the change in the micro and macro geometry of the grinding wheel can be determined by a non-contact way by supplying jet of air through the nozzle of a pneumatic-electric-contact converter to the surface of the tool during operation. To confirm this hypothesis an experiment was did on a surface grinding machine. Various samples were machined, that led to self-sharpening of the tool. Grinding wheel monitoring system was developed for the experiments. System includes a device that provides the setting of the necessary working gap between the nozzle and the controlled wheel. A justification is proposed for determining the frequency of grinding wheel grinding during operation by accurately accounting for changes in the state of its surface without stopping the machining process.

Effects of the Grinding Wheel Eccentricity and Waviness on the Dynamics of Tool Grinding

The complex dynamics of grinding repeatedly cause critical or unstable process conditions. For a better understanding and prediction of such occurrences, the dominant excitation phenomena need to be identified and their interrelation with the system dynamics have to be analyzed.Based on measurements of the excited frequencies in several operation modes of the grinding machine, the grinding wheel rotation is identified as a major excitation source. Further analysis of the grinding wheel surface displays three main components that define the excitation frequencies of the system; these are the eccentricity, waviness and roughness (also named wheel topography). Moreover, the wheel topography and thus the excitation frequencies can change over time due to excessive wear.Following the experimental results, a grinding wheel topography and wear model are developed and included in an integrated simulation of tool grinding. The analysis of the calculated cutting forces in the frequency domain confirm the excitation due to the grinding wheel topography.Firstly, this work has extracted the grinding wheel as a prominent excitation mechanism and reproduced it with the developed grinding model. Secondly, we have evidence that a complete description of the complex grinding process is only possible when considering the interdependence between system dynamics, wheel kinematics and the grinding process.

Werkzeugschleifen mit Hybridschleifscheiben*/Tool grinding with hybrid bond grinding wheels

Die Herstellung von Spannuten an Schaftwerkzeugen erfolgt in den meisten Fällen über Schleifprozesse. Dabei kommen bei der Fertigung von Hartmetallwerkzeugen Diamantschleifscheiben verschiedener Bindungsspezifikationen zum Einsatz. Neuartige Hybridbindungen versprechen Vorteile gegenüber den konventionellen Bindungen. In umfangreichen Untersuchungen wurden verschiedene Bindungsspezifikationen bezüglich der Prozesskenngrößen und des Arbeitsergebnisses untersucht und gegenübergestellt.   The production of flutes at end mills is often carried out by creep feed grinding processes. During the manufacturing of cemented carbide tools diamond grinding wheels with different bonding specifications are used. Novel hybrid bonding grinding wheels promise advantages compared to conventional bonds. During extensive investigations different bonding specifications are analyzed and compared concerning their process parameters and the work result.