Influence of processing parameters on tool life in machining the heat-resistant molybdenum-based MoTiC alloy

Introduction. Modern mechanical engineering is characterized by the increasing application of heat-resistant alloys for critical components in aerospace and defense equipment. The machining of promising molybdenum alloys, such as Mo-30TiC, is particularly challenging due to their high heat resistance, abrasiveness, and the anomalous behavior of their mechanical properties at elevated temperatures. Existing technological solutions developed for nickel-based alloys often prove ineffective, highlighting the relevance of research in this area. Purpose of the work is to develop rational machining conditions and strategies for the milling of the heat-resistant Mo-30TiC alloy, aimed at increasing tool life and ensuring the required surface quality. Methodology. Experimental studies were conducted on an Okuma MB-46BE machining center using carbide end mills from various manufacturers. The influence of geometric tool parameters (rake angle, cutting edge radius, and presence of a negative land) and cutting conditions (cutting speed, feed rate, depth of cut) on flank wear and surface roughness was investigated. Process monitoring was performed using optical microscopy and surface profilometry. Results and discussion. Optimal geometric tool parameters were determined: a rake angle of 0°, a cutting edge radius of 0.5–1 mm, and a negative land width of 0.05 mm. Two distinct machining strategies were developed: a standard cutting strategy (Vc = 50–72 m/min, fz = 0.03–0.04 mm) for high-quality finishing, and a high-productivity power cutting strategy (Vc = 12–17 m/min, fz = 0.08–0.1 mm). The Karcan 99508003 and CNCINS MS15.Z5.08.19.63.38.R05 end mills demonstrated superior tool life. It was shown that the progression of tool wear leads to an exponential increase in the variance of surface roughness parameters Ra and Rz. Conclusions. The proposed set of technological solutions enables effective machining of the Mo-30TiC alloy, providing control over tool wear and achieving the specified surface quality. The results of this work are of practical importance for manufacturing enterprises specializing in the machining of difficult-to-cut materials.