GRINDING FEEDS AND SPEEDS Machinery's Handbook, 31st Edition
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User Calibration of Recommendations It is recommended to copy or redraw the standard graph for any of the material groups before applying the data calibration method described below. The method is based on the user’s own experience and data. The procedure is described in the following and il- lustrated in Table 11 and Fig. 12. Only one shop data set is needed to adjust all four Taylor lines as shown below. The required shop data is the user’s wheel-life T U obtained at the user’s wheel speed V U , the user’s work speed V wU , and depth of cut a r . 1) First the user finds out which wheel-life T U was obtained in the shop, and the corre sponding wheel speed V U , depth of cut a r and work speed V wU . 2) Second, calculate: a) ECT = V wU 3 ar ÷ V U b) the user Taylor constant C U = V U 3 T U 0.26 c) V 100 U = C U ÷ 100 0.26 d) V 10 U = C U ÷ 10 0.26 3) Thirdly, the user Taylor line is drawn in the pertinent graph. If the user wheel-life T U is longer than that in the standard graph the speed values will be higher, or if the user wheel-life is shorter the speeds C U , V 10 U , V 100 U will be lower than the standard values C, V 10 and V 100 . The results are a series of lines moved to the right or to the left of the standard Taylor lines for ECT = 17, 33, 50 and 75 3 10 − 5 mm. Each standard table contains the values C = V 1 , V 10 , V 100 and empty spaces for filling out the calculated user values: C U = V U 3 T U 0.26 , V 10 U = C U ÷ 10 0.26 and V 100 U = C U ÷ 100 0.26 . Example 7: Assume the following test results on a Group 6 material: user speed is V U = 1800 m/min, wheel-life T U = 7 minutes, and ECT = 0.00017 mm. The Group 6 data is repeated below for convenience. Standard Table Data, Group 6 Material ECT = 0.00017 mm ECT = 0.00033 mm ECT = 0.00050 mm ECT = 0.00075 mm Constant C = 5290 Constant C = 4690 Constant C = 3585 Constant C = 2395 V T SMRR V T SMRR V T SMRR V T SMRR 100 1600 270 1415 465 1085 540 725 540 10 2910 495 2580 850 1970 985 1315 985 1 5290 900 4690 1550 3585 1795 2395 1795
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ECT = 17 ECT = 33 ECT = 50 ECT = 75
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ECT = 17 ECT = 33 ECT = 50 ECT = 75
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Fig. 11b. SMRR versus V , T = 100, 10, 1 minutes
Fig. 11a. Group 6 Tool Steels, T - V
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