80% Core - Speeds and Feeds

Parameter

Formulas

Cutting Speed
(SFM)

SFM= .262 x D1 x RPM

Revolutions Per Minute
(RPM)

RPM = 3.82 x (SFM/D1)

Feed Rate
(inches per minute)

F1 = F2 x N x RPM

Feed Per tooth
(inches)

F2 = F1/(N x RPM)

Cutting Time
(minutes)

T = L/F1

Rate of Metal removal
(cubic inches per minute)

MRR = W x D xF1

Symbol Definitions

D1 = Diameter of milling Cutter (inches)

RPM = Revolutions per minute

SFM = Cutting speed (feet per minute)

F1 = Feed rate (inches per minute)

F2 = Feed (inches per tooth)

N = Number of teeth in cutter

MRR = Rate of metal removed (cubic inches per minute)

T = Cutter time (minutes)

L = Length of cut (inches)

D = Depth of cut (inches)

W = width of cut (inches)

Type Of Application

Speed (SFM)

1/32"

1/16"

3/32"

1/8"

3/16"

1/4"

5/16"

3/8"

1/2"

Finishing

500

0.00015

0.0003

0.0004

0.0006

0.0009

0.0012

0.0015

0.0018

0.0025

Roughing & Semi Finishing

250

0.0005

0.001

0.0015

0.002

0.003

0.004

0.005

0.006

0.008

Reduce feed rate by 20% for every 2" increment.