The impact of airborne emissions from coolants and lubricants on machining costs

Abstract

A novel aerosol evaluation cell was employed to measure particle number and mass concentration, with a size distribution from nano to micro scale. Different cooling/lubrication and airflow extraction scenarios were tested on a CFRP/Ti6Al4V case study, and the particle concentrations were measured to evaluate their effect on productivity and cost per hole, if current occupational exposure limits are respected. Aspects to achieve sustainable machining like tool life, consumption of coolant and energy, and standby time required to safely open the machine-tool doors were considered. LCO2 delivered the best productivity and cost results as it improved the tool life by 40 % compared to MQL, while eliminating the need for standby time to evacuate particles.