Okuma OSP-P20L - Page 114

5238-E P-101
SECTION 7 FIXED CYCLES
[Supplement]
When determining the F word value, use the following equation:
Using the equation above, the F value can be calculated as follows:
D = n × (F0 _ )
where,
D : displacement after "n" revolutions, (mm)
n : number of revolutions required for displacement D, min
-1
{rpm}
F
0 : thread lead at start of thread cutting cycle
E : lead variation amount per revolution
_ : increasing or decreasing lead
"+" : increasing lead
"–" : decreasing lead
+
+
2
n × E
42 = 7 (F0 + )
F0 = 2.5
2
nE
2
7×1
D = n × (F
0 + )