Useful Formulas
| Standard Feed and Speed Formula |
| SFM |
= |
RPM x DIA x .262 |
|
SFM |
= |
Cutting speed (feet/min) |
| RPM |
= |
(SFM x 3.82) / DIA |
|
RPM |
= |
Spindle speed (rev/min) |
| IPM |
= |
IPT x N x RPM |
|
IPM |
= |
Feed rate (inches/min) |
| IPT |
= |
IPM / (N x RPM) |
|
IPT |
= |
Feed per tooth (inches) |
| FPR |
= |
IPM/RPM |
|
DIA |
= |
Effective cutting diameter (inches) |
|
|
|
|
N |
= |
Number of Teeth |
|
|
|
|
FPR |
= |
Feed / Revolution |
| Standard Horse Power Calculations |
| MRR |
= |
W x IPM x DOC |
MRR |
= |
Metal removal rate (inch3/min) |
|
|
|
W |
= |
Width of cut (inches) |
|
|
|
DOC |
= |
Depth of cut |
| HPs |
= |
MRR x K |
HPs |
= |
Horse power at spindle |
|
|
|
K |
= |
Power factor (HP/inch3/min) |
|
|
|
Steel |
K = 1 |
|
|
|
Cast Iron |
K = 0.5 |
|
|
|
Aluminum |
K = 0.25 |
| Metric Feed and Speed Formula |
| V |
= |
(n x DIA) / 318 |
V |
= |
Cutting speed (m/min) |
| N |
= |
(v x 318) / DIA |
N |
= |
Spindle speed (rev/min) |
| S |
= |
s/z x z x n |
DIA |
= |
Effective cutting diameter (mm) |
| S/Z |
= |
s / (z x n) |
S/Z |
= |
Feed rate per insert (mm/insert) |
|
|
|
S |
= |
Feed rate (mm/min) |
|
|
|
Z |
= |
Number of teeth |
| Metric Horse Power Calculations |
| Q |
= |
W x S x A |
Q |
= |
Metal removal rate (cubic cm/min) |
|
|
1000 |
W |
= |
Width of cut (mm) |
|
|
|
S |
= |
Feed rate(mm/min) |
|
|
|
A |
= |
Depth of cut (mm) |
| HPs |
= |
Q |
HPs |
= |
Horse power at spindle |
|
|
K |
K |
= |
Power factor (HP/CM3/min) |
|
|
|
Steel |
K = 16 |
|
|
|
Cast Iron |
K = 32 |
|
|
|
Aluminum |
K = 64 |
|
