Flow Field Measurements Of The Grinding Cooling Liquid Jet

Abstract

The workpiece cooling by metalworking fluids, which has a significant influence on the workpiece surface layer quality, is not fully understood for industrial grinding processes. This necessitates a significant effort in determining optimal cooling conditions empirically, raising part manufacturing costs. As a solution, a measurement method for the metalworking fluid flow field near the grinding wheel is desired to close the knowledge gap. However, the fluctuating curved surfaces of the coolant cause unpredictable light deflections and reflections, making optical flow measurements difficult. To evaluate the effect of light deflections on the coolant flow measurements, particle image velocimetry is applied in combination with background-oriented schlieren and a ray-tracing approach. Here we study coolant flow measurements in a grinding machine for in-process supply conditions, at first without a working piece and with a focus on the measurability and reliability of the coolant flow from the nozzle exit to the interaction with the rotating grinding wheel. As a result, for the nozzle flow, a systematic measurement deviation of up to 2 % is identified and after the correction, a plausible flow behaviour is obtained. Furthermore, the in-situ measurements of the coolant flow in interaction with the grinding wheel reveal a detailed description of the fluid-workpiece interaction.