Influence of the shape of the toroidal flank surface on the cutting wedge angles and mechanical stresses along the drill cutting edge

OBRABOTKAMETALLOV Vol. 23 No. 3 2021 MATERIAL SCIENCE EQUIPMENT. INSTRUMENTS 5 4 3 Ta b l e 5 Results of an epure of equivalent stresses and displacements along the cutting edges of drills with different parameters of the flunk surface Conical flank surface Toroidal flank surface (2.5 R) Toroidal flank surface (1.25 R) Toroidal flank surface (Rt min) σ, MPa Ψ,° λ,° σ, MPa Ψ,° λ,° σ, MPa Ψ,° λ,° σ, MPa Ψ,° λ,° 1064.85 29.0289 5.8 740.4581 32.0511 0.891 557.1906 36.3369 17.82 499.1 46.81 60 1039.035 27.825 3.8 741.7603 29.9989 0.956 558.1982 33.0369 10.63 462.4 40.6211 40.52 802.4772 25.7869 1.33 694.3632 27.3139 1.052 424.1168 29.4411 5.36 217.7 34.7439 24.7 681.772 22.1639 1.2 622.1755 23.2369 1.124 433.9531 24.7761 2.13 207.4 28.6361 5.26 595.8291 15.1731 2.33 585.3223 15.8989 1.112 722.0529 17.0239 2.09 390.2 20.065 0.75 460.658 0 4 458.2239 0 1.326 654.7368 0 1.016 226.3 0 1.5 shown in table 5 and on its basis a graph of the dependence of stress on the angular position of the control point on the cutting edge in the instrumental coordinate system is plotted (fig. 10, 11). It is found that in the case, when the radius of the generatrix of the flank surface reduces, the length of the cutting edge increases, which leads to an integral decrease in stresses in the cutting wedge along the entire cutting wedge and proves a more rational assignment of geometric parameters along the cutting edge. Fig. 10. Graph of variance in internal stresses of the drill structure relative to the angular position of the measurement point on the cutting edge Fig. 11. Combined graph of the dependence of the cutting edge angle and equivalent stresses in the drill design on the angular position on the cutting edge

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