Machinery's Handbook, 31st Edition
Machining Power
1149
f t = feed per tooth; in/tooth, or mm/tooth f m = feed rate; in/min or mm/min d t = maximum depth of cut per tooth: inch, or mm d = depth of cut; inch, or mm
n t = number of teeth on milling cutter n c = number of teeth engaged in work w = width of cut; inch, or mm
Table 4. Machine Tool Efficiency Factors, E
Type of Drive Direct Belt Drive Back Gear Drive
Type of Drive
E
E
0.90 0.75
Geared Head Drive Oil-Hydraulic Drive
0.70-0.80 0.60-0.90
Table 5. Formulas for Calculating the Metal Removal Rate, Q
Metal Removal Rate
For Inch Units Only Q = in 3 /min
For SI Metric Units Only Q = cm 3 /s
Operation
Single-Point Tools (Turning, Planing, and Shaping)
V fd 60
12 Vfd
, f wd 60 000 m V un d 60 c t
Milling
f m wd
Surface Broaching
12 Vwn c d t
Example: A 180-200 BHN AISI 4130 shaft is to be turned on a geared head lathe using a cutting speed of 350 fpm (107 m/min), a feed rate of 0.016 in/rev (0.40 mm/rev), and a depth of cut of 0.100 inch (2.54 mm). Estimate the power at the cutting tool and at the motor, using both the inch and metric data. Inch units:
K p = 0.62 (from Table 1b) C = 0.94 (from Table 2) W = 1.30 (from Table 3) E = 0.80 (from Table 4) Q = 12 Vfd = 12 3 350 3 0.016 3 0.100 (from Table 5) Q = 6.72 in 3 /min P c = . . . . . K CQW 062 094 672 130 51hp p # # # = = P m = . . E P 080 5 64hp c = =
SI metric units:
K p = 1.69 (from Table 1b) C = 0.94 (from Table 2) W = 1.30 (from Table 3) E = 0.80 (from Table 4) Q = . V fd
. 60 107 040 254 181cm 3 = × × = (from Table 5) . / s
60
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