In-Line Concentration Monitoring of Water-Soluble Cutting Fluids Using an Automatic Brix Meter

Water-soluble cutting fluids are routinely used as coolants and lubricants in the metalworking process. The properties of these water-soluble cutting fluids change during operation. In the management of the properties of water-soluble cutting fluids, it is crucial to maintain the concentration within an appropriate range. In typical manufacturing facilities, the concentration of water-soluble cutting fluids is measured using Brix. The commonly used Brix meters are of the sampling type. However, measuring the concentration of cutting fluids in numerous machine tools can be time-consuming. In addition, there has been a recent demand for automated measurement and management of concentration and data accumulation. In recent years, relatively inexpensive automatic Brix meters have become available in Japan. In this study, we tried to continuously measure the concentration of water-soluble cutting fluids using an automatic Brix meter. We installed an automatic Brix meter in a tank that continuously circulates 40L of water-soluble cutting fluid and measured it for several tens of days, confirming that it can measure stably. However, depending on the type of water-soluble cutting fluid, the measurement results may become unstable immediately after starting the measurement. Therefore, it was found that the choice of the water-soluble cutting fluid to be used is also important for the concentration measurement by the automatic Brix meter.