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

OBRABOTKAMETALLOV Vol. 23 No. 1 2021 TECHNOLOGY Fig. 4. Dependence of the cutting forces on the machining time: 1 – V = 50 m/min; 2 – V = 35 m/min; 3 – V = 25 m/min Fig. 5. Dependence of fl ank wear on the milling con fi guration: 1 – mill No. 1; 2 – mill No. 2; 3 – mill No. 3 wear becomes critical, which varies in the range from 0.11 to 0.15 mm, there is an instantaneous increase in forces. It follows that before the onset of critical wear, there is no in fl uence of the milling width to depth ratio on the cutting forces. The change in the forces for different ratios t to B (with the same volume of the cut layer per unit of time, i.e. tB = constant, at S = constant) is explained only by the different wear of the mills, which is fully con fi rmed by Fig. 5 and 6. The research revealed that wear prevails on the fl ank surface of the mill tooth. Notably, the uneven wear is mainly caused by mechanical abrasion (Fig. 7–9). The analysis of the established dependencies graphs and photos of the mills’ wear reveals that the most effective is the processing technique of mill No. 3 with a depth to width ratio of 1:16. This is assumed to be due to the lower bending moment acting on the mill during operation and to a more uniform distribution of the cutting temperature along the cutting edge. The force graphs demonstrate that for different t to B ratios with the same volume of the cut layer, the values of the cutting forces before the onset of critical wear are approximately the same, but if the distributed load along the cutting edge is replaced by a concentrated force, the point of this force application will be different, as shown in Fig. 10.