Investigation of the machinability of AISI O2 tool steel in milling using minimum quantity lubrication method (MQL)

AISI O2 is some sort of tool steel that is frequently used in manufacturing industry. It is prefered that due to capability of high hardenability and feature of mechanic. Machinability is also important in addition to cost of production in manufacturing industry. Cutting forces have an important place in description of cutting tool life and roughness of surface. Increasing production cost in these days and diffuculties of waste disposal which composed after manufaturing has prompted researchers to alternative production method that can more clean and sustainable. In this study, optimum cutting parameters were determined with sintered carbide cutting tools on AISI O2 tool steel and processed with dry cutting conditions using by minimum amount of lubrication method. After every process, surface roughness were evaluated from 7 different points with device of Mitutoyo Surftest SJ-310 and minimum surface roughnesses and average surface roughnesses were measured. Cutting forces were measured and analyzed for each cutting depth with Kistler 9757B of dynomometer which connected to platform. The wear amount of cutting tools which cleaned were observed after the each process of cutting depth with microscope of Vision SX 45 Stereo zoom and images of wear were saved. The wear types of weared cutting tool were observed with MIAI3 TESCAN scanning electron microscope which have high magnification ratio.The surface roughness of the workpiece treated with the minimum amount of lubrication was significantly reduced compared to dry cutting conditions.There was also a significant reduction in cutting forces. Increased tool life was observed with minimum lubrication effect. When the surface roughness obtained was taken into consideration, the lowest surface roughness value was obtained with 0,108 µm cutting speed Vf= 150 m/min, fz= 0,05 mm/tooth feed rate and 150 ml/hour lubrication amount. In terms of tool life, the best results were obtained with a cutting speed of 9,15 m with a cutting speed of Vf= 125 m/min, fz = 0,15 mm/feed rate and 50 ml/h lubrication. The resultant shear forces obtained by milling were obtained with the lowest resultant shear force value of FR= 96.98 N with a feed rate of 0,05 mm/tooth and lubrication amounts of 100 ml/hour for the 125 m/min cutting speed. The minimum amount of lubrication method has a positive effect on the machining of AISI O2 tool steel by using sintered carbide coating cutting tool with determined process parameters.