OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 4 No. 1 2022 In the absence of vibrations, the indicator ( , ) cm a y z can be calculated according to the dependence [21]: 2 3 5 3/2 3 3 2 ( )( ) 2 8 ( , ) 5 15 8 g c g k u f cm y y y u u n K V V t y z z a y z z L L L V H (19) When substituting the above values of the parameters into expression (19), we obtain the value of the indicator in the absence of vibrations: 6 6 6 6 2 cm 6 3/2 3 3.14 15.86 10 1 2 7.31 10 (35±0.25)(11.54 10 -10.38 10 ) , 8 0 ( ) .25(11.54 10 ) a y z 3 5 3 3 3 4 4 3 4 2 0.136 10 0.136 10 8 0.136 10 3.397 10 = 0.014 15 5 3.397 10 3.397 10 . The absolute error A of calculations is cm , ( , ) 0.014 0.313 0.299, ( ) A a y z a y z and relative error A of calculations is: 0.299 100 % 100 % 95.5 % ( , ) 0.313 A A a y z . Experimental studies were carried out to verify the calculation results. On a Knuth RSM 500 CNC machine, holes with a diameter of 150 mm in workpieces made of titanium alloy VT3-1 with a tool AW 60 × 25 × 13 63C F90 M 7 BA 35 m/s (at a wheel speed of 35 m/s, a workpiece speed of 0.25 m/s, longitudinal feed – 33 mm/s, transverse feed – 0.005 mm/stroke). Profi le diagrams were taken from the prototypes after the grinding operation, according to which the value of the indicator experiment( , ) a y z was estimated (Table 1) and the relative error was determined (Table 2). The probability of an event characterizing removing the surface layer at the level y = 0.004 mm at the value of the indicator a0 = 0.545 is calculated according to the equation by substituting the calculation results ( , ) a y into expression (4): 0 ( , ) 0.545 0.282 ( ) 1 exp 1 exp 0.576. a a y P M The probability of no material removal, as an opposite event, can be determined from the total probability formula: ( ) 1 ( ) 1 0.576 0.424. P M P M Ta b l e 1 The values of the indicator a characterizing the change in the probability of material removing at the considered level The value of the indicator a characterizing the change in the probability of material removing at the considered level Номер опыта 1 2 3 4 5 experiment( , ) a y z 0.392 0.313 0.264 0.4 0.305 cm( , ) a y z 0.014 ( , ) a y z 0.282
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