Any metalworking facility, whether large or small, will realise the importance of maintaining engineering fluids if tool life and product quality is to be maintained. This applies to all segments of the marketplace, whether the facility is involved in milling, turning, cutting, extruding, compressing, or immersing etc. The engineering fluid’s main functions’ are to cool the tool/product interface and to lubricate the same. Other functions include the prevention of welding between the contact edges, washing away the swarf preventing scratching and helping to prevent corrosion.
Engineering fluids are typically made up of a mixture of oil (mineral, vegetable or synthetic) and water that form an emulsion. This combination gives the best performance as the heat transfer characteristics of water are ideal and the oil is an excellent lubricator. Oil and water is mixed to a predetermined concentration and is monitored by the machine operator on a regular basis using an instrument such as the robust Eclipse optical refractometer or the new digital OPTi-Coolant manufactured by Bellingham + Stanley to make sure evaporation hasn’t affected the mixture ratio.
As well as monitoring concentration, pH is also monitored in order to reduce bacterial growth within the system. Commonly this is done using a dipping paper and colour comparison chart; however, many companies now use digital meters such as the new EcoSense® pH PEN available from Bellingham + Stanley for this purpose as it provides a digital readout out of pH to help eliminate human error. Some operators also measure conductivity to check for impurities such as salt ions.
For large machine shops where multiple machines are supplied from a single coolant tank, on-line instrumentation that continually monitors concentration, pH and conductivity are also available. Please visit www.refractometershop.com