Metalworking fluids are used to cool and lubricate the machining activity, prolong the life of the tool, carry away debris and protect the surfaces of the work pieces. The metalworking fluid is a complex mixture, which may contain oil, additives such as biocides and rust inhibitors etc. as well as contaminants like metal fines, tramp oil and bacteria.
During machining, mist is produced by the interaction of the fluid with the moving parts. When liquid hits fast moving parts, it is thrown back and dispersed as fine droplets. The generation of mists are mainly depending on:
- Higher speed of tool = higher generation of mist
- The volume, rate and point of delivery of metal working fluid to the cutting edge.
If metalworking fluids become excessively hot they may start to ”burn” and degrade. During machining of metal parts reaching a high temperature, such as grinding procedures, smoke may be visible.
The gaseous state of any liquid is formed as molecules leave (evaporate from) the surface of the liquid. The evaporation increases with low boiling point of the liquid and increased temperature of the fluid. In water based emulsion the evaporation will increase the humidity in the plant.