Cutting fluid aerosol generation in near-dry turning

The generation of aerosol using the cutting fluids in machining processes presents a concern from the standpoint of pollution to the environment. Near-dry machining, as a method of applying only a minute amount of cutting fluid, has been developed to address the air quality issue. This paper presents the establishment of an analytical method to quantitatively predict the air quality in the near-dry turning operation. The analytical prediction is based on the modelling of cutting temperature, aerosol generation mechanism and spatial and temporal diffusion. The cutting temperature model is obtained by considering moving and stationary heat sources in the cutting tool. The aerosol generation mechanism model contains two primary parts: the evaporation mechanism due to high temperature in the cutting zone and the air blast splash mechanism due to the kinetic energy of the air-fluid mixture under the near-dry condition. The diffusion model provides the calculation of the aerosol concentration at a distance from the cutting zone as a function of time due to the concentration gradient. The calibration and validation of the model have been performed experimentally with the use of light-scattering particle counting under various cutting conditions. Results show that the model agrees well with the measurements and that, under normal cutting conditions, the cutting fluid flow rate is the dominant factor for the aerosol generation rate.