Investigation of the machinability by milling of the laser sintered Inconel 625/NiTi-TiB2 composite

OBRABOTKAMETALLOV Vol. 23 No. 1 2021 TECHNOLOGY a b c Fig. 2. Milling technique Fig. 3. Dependence of fl ank wear on the machining time: 1 – V = 50 m/min; 2 – V = 35 m/min; 3 – V = 25 m/min mill operating at a cutting speed of 25 m/min experienced the least wear during the experiment time. Thus, at the 28th minute of operation, the wear chamfer on the fl ank surface reached 0.11 mm. The mill operating at V = 50 m/min has the greatest wear since the chamfer value reaches 0.11 mm in 14 minutes. Obviously, the growth of forces in the experiment time is caused by the wear of the mills (Fig. 4). The mill operating at V =50 m/min (curve 1 ) demonstrates the most intensive growth of cutting forces in the entire studied range. For mills operating at speeds of 35 and 25 m/min, the increase in cutting forces over time also correlates with the amount of wear but is less intense than for the mill cutting at the speed of 50 m/min. Figure 5 shows the wear dependences, and Figure 6 shows the dependences of the cutting forces on the operating time for different ratios of the milling depth and width. After 40 minutes of milling, there occurs critical wear of mills No. 1 and 2 with the cutting edge being painted out. The mill No. 3 working at a ratio of 1:16, worked signi fi cantly longer than the others (117 minutes) and was not subjected to catastrophic wear with the destruction of the edge. A sharp increase in the wear intensity of mill No. 3 occurred only at the 92nd minute, after the wear chamfer value exceeded 0.15 mm, while the mills No. 1 and 2 reached this wear value at the 32nd and 43rd minutes, respectively. The maximum value of the wear chamfer of mill No. 3 after 117 minutes of operation was 0.28 mm. The graph of forces (Fig. 6) demonstrates that the forces had very similar values for the mills working time from 0 to 40 minutes for different ratios of the milling depth and width. This is explained by the same volume of the cut layer per unit of time. However, as soon as the