Study on Evaluation of Cutting Fluid Using End Face Cutting in Lathe Machining

Currently, functional tests and property tests are used to evaluate cutting fluid [1]. However, the problem is that the results obtained from above tests do not always match with each other because the insert tip is under extreme pressure and high temperature in actual machining. Therefore, a new cutting fluid evaluation method based on actual machining is needed. End face cutting in lathe machining is cutting workpiece from outside to center. In this study, rotation speed was fixed. In other words, cutting speed varies with the radius of workpieces and it is considered possible to clarify the effectiveness of cutting fluid at each cutting speed in a single cut.The performance of the cutting fluid was evaluated based on acceleration of cutting tool and surface roughness of workpiece. The following results were obtained. In steel materials, the acceleration of insoluble cutting oil was highest, and burnt insert tips were observed after the end face cutting. Insoluble cutting oil used in this study has a lower viscosity and a lower boiling point than mineral oils and esters. The highest acceleration of insoluble cutting oil is considered to be due to insufficient lubricating effect because of evaporation of it. No effect of insoluble cutting oil, mineral oils or esters was obtained on surface roughness. The acceleration of undiluted solution is higher than that of diluted solution and burnt insert tips were obtained. The cooling effect of undiluted solution is low because of less water. The highest acceleration of undiluted solutions is considered to be due to insufficient lubricating effect because of evaporation of it. In A5056, surface roughness of the diluted solution was higher at low cutting speed due to lack of lubricating effect. Differences in acceleration, surface roughness and insert tip were observed for each oil type, indicating the possibility of evaluating cutting fluid performance using the method proposed in this study.