Investigation on Cutting Force Reduction of Eco-friendly Cutting Fluids with Castor Oil and Additives in Broaching

At present, the traditional cutting fluids usually containing the chemical toxicity or physical irritating ability will cause illness or injury in workers. Therefore, research on eco-friendly cutting fluids has become a mainstream trend in the development of metalworking process with a type of coolant and lubricant. In this present work, three types of eco-friendly cutting fluids including distill water, castor oil, linear alkyl benzene sulphonic acid (LAS-Na) and nanographite by different proportion under ultrasonic vibration were prepared. Then they were assessed by the comparisons of cutting forces in broaching under the condition of micro-atomization spraying. After that, the optimum ratio of each type of cutting fluid was gained based on the reductions of broaching forces. Physical stability, droplets distribution and wettability of those optimal type of eco-friendly cutting fluid were measured. On the basis of characteristics, the metal-cutting principle with those experimental types of cutting fluids was discussed. Results shows that the surfactant of LAS-Na could effectively prevent the coalescence of oil droplets and decrease the average diameter of droplets so that enhanced wettability, but the nanographite was strongly influenced by the cleaning effect of LAS-Na. Moreover, reduction in broaching force was caused by the mechanism of the best adsorption and the best permeability with the effect of the surfactant of LAS-Na.