MACHINING ECONOMETRICS Machinery's Handbook, 31st Edition
1206
1000
H-CURVE
100
10
1
0.1
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
0.9 1
ECT , mm
Fig. 11b. Tool Life versus ECT The Force Relationship: Similar tests performed elsewhere confirm that the F H / F C function can be determined using the 5 tool life constants ( H , K , M , L , N 0 ) introduced previously, and a new constant ( L F / L ).
2
M x H 4 −
h
^
K y
− −
F F
1 c
ln a
C H
(5)
m
=
L
F
N Lx 0 −
h
^
L
The constant a depends on the rake angle; in turning, a is approximately 0.25 to 0.5 and L F / L is 10 to 20. F C attains it maximum values versus ECT along the H -curve, when the tool life equation has maxima, and the relationships in the three force ratio planes look very similar to the tool life functions shown in the tool life planes in Fig. 6a, Fig. 6b, and Fig. 6c.
1000
L F /L = 5 L F /L = 10 L F /L = 20
100
10
1
1
0.1
FH /FC
Fig. 12. Tool Life versus F H / F C Tool life varies with F H / F C with a simple formula according to Equation (5) as follows: T aF F C H L L F = c m
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