Investigation of the machinability of AISI D2 tool steel in milling using minimum quantity lubrication method (MQL)

AISI D2 steel is tool steel commonly used in the machining industry. It is preferred because of its high hardness. In machining, the surface roughness of the part produced, the cutting forces during the production period and the cutting life of the cutting tool used are also important besides the production cost. Nowadays, researchers are trying to develop technologies that do not harm the environment and reduce production costs in order to prevent environmental damage caused by increasing production costs and the residues of coolant used during production. In our study, dry machining and milling using the minimum amount of lubrication (MQL) system are performed under suitable cutting parameters that we have determined with sintered carbide cutting tools of AISI D2 tool steel. After each milling process, the surface roughness values are measured with Mitutoyo Surftest SJ-310 surface roughness meter from seven points on the workpiece and their averages are recorded. The cutting forces that occur during each milling process are measured with the Kistler 9757B model cutting force measuring device, which is connected to the table of the vertical machining center and is recorded. Wear images are determined by Vision SX 45 Stereo Zoom microscope and wear size is measured to monitor the wear occurring in the cutting tool after each milling process. The wear types of cutting tools are also determined by scanning electron microscope with high magnification and EDS feature MIAI3 TESCAN model. With the Werte Micro STN 25 MQL system used in the thesis, the lubricating fluid to be used during milling process is sprayed. Considering the surface roughness obtained, the lowest surface roughness value was obtained with 0.166 0,1m cutting speed Vf = 125 m / min, fz = 0.1 mm / thread feed rate and 50 ml / hour lubrication amount. In terms of tool life, the best results were obtained with a cutting speed of 11.85 m with a cutting speed of Vf = 75 m / min, fz = 0.05 mm / thread feed rate and 50 ml / h lubrication. The minimum resultant shear force obtained by milling was obtained with Fr = 59,764 N and V = 75 m / min cutting speed, 0.075 mm / thread feed and 100 ml / hour lubrication parameters. It is seen that minimum amount of lubrication method has positive effect on machining of AISI D2 steel by using sintered carbide cutting tool with determined process parameters.