Machining Formulas & Technical Information
Download the Korloy insert crossover & cutting calculator app HERE
M.A. Ford speed and feeds HERE
SFM = 0.262 x D x RPM
RPM = (3.82 x SFM) / D
IPR = IPM / RPM or CHIP LOAD x F
IPM = RPM. x IPR
CHIP LOAD = IPM / (RPM x F) or IPR / F
Terms

Flutes(F)  Number of flutes

Diameter(D)  Diameter of cutter

Chip load  The amount of material removed by each flute of the cutter.

Feed Rate or Feed per tooth  The inches per minute of workpiece movement toward the cutter between each tooth

Inches Per Minute(IPM)  Number of linear inches the cutter passes through the workpiece in one minute

Depth of Cut (DOC)  The depth of cut of the end mill into the part surface axially. With CNC milling, it is measured in the Z axis direction.

Inches Per Revolution (IPR)  Feed rate of the cutter for each revolution of the cutter. In the inch system, the feed rate of the cutter can be calculated for each revolution of the cutter.

I.P.R. = Chip load x Number of flutes


Millimeters Per Revolution (MMPR)  Feed rate of the cutter each revolution of the cutter. In the metric system, the feed rate of the cutter can be calculated for each revolution of the cutter.

M.M.P.R. = Chip load x Number of flutes


Meters Per Minute (MPM)  The cutting speed of the end mill. This system is used in all countries that use the Metric system. MPM represents the rate of the surface of the cutter passes over the surface of the part. Cutting speed is measured in Meters per minute.

Revolutions Per Minute (RPM)  The spindle speed rate of the cutter. This value will be calculated from a selected SFPM or MPM.

Surface Feet Per Minute (SFPM)  The is the cutting speed of the end mill in the United States. It is the number of feet per minute that a given point on the circumference of a cutter travels per minute.

Width of Cut  (maximum amount should not exceed 2/3 x Cutter diameter)
SELECTING SPEED AND FEED RATES AND THE DEPTH OF CUT
The following items must be selected by the machinist / programmer when using end mills.
SFPM  cutting surface speed

Chip Load  material removal rate

Depth of Cut  depends on specific part applications requirements

Considerations  cutting depth never to exceed flute length

Excessive depth of cut will result in tool deflection. As required, the depth of cut increases use the largest diameter cutter available to maintain a depth to diameter ratio of 1 : 1.