Evaluation of tool life - tool wear in milling of inconel 718 superalloy and the investigation of effects of cutting parameters on surface roughness with taguchi method

Abstract

In this study, the effects of cutting speed, milling direction (down milling, up milling), coating layer (TiAlN and TiAlN-TiN) and the number of inserts of tool holder on the surface roughness and tool life in dry milling of Inconel 718 superalloy were investigated. In the first place, the effects of control factors on the tool life were studied at the cutting speeds of v = 50 m/min and v = 100 m/min. The alternation of flank wear depending on the cutting time was examined. The types of wear and wear mechanisms were determined by examining the optical images of worn tools. In the second part of the study, for the purpose of investigating the effects of control factors on the surface roughness, L16 Taguchi Technique was used and the optimal control factor levels, giving the lowest value of the average surface roughness parameter (Ra) were determined. The effect of cutting speed on the tool life was more than the effects of the milling type and number of inserts. Down milling resulted in longer tool life compared to up milling method. In up milling, longer tool life was obtained with 2 inserts at low cutting speeds and with 4 inserts at high cutting speeds. TiAlN- TiN coated tools exhibited twice as long tool life than the TiAlN coated tools. For both milling methods, the most effective wear types were flank wear and nose wear.