Milling Metric Cutting speed calculation

Cutting Speed ​​and Feed in Milling Operation

Cutting speed in milling process is the ability of the milling cutter cutting workpiece with a speed that is calculated by multiplying the circumference of the milling cutter diameter with the number of length in a minute.

Factors affecting Cutting Speed:

1 Hardness (hardness)

Soft material    vs    Hard Material
High CS          vs    Low CS


2. ductility (ductility)

ductile material vs  Brittle material

High CS          vs    Low CS


3. tensile stress (tensile strength)
High tensile      vs  low TensileLow CS          vs    High CS


To determine the cutting speed can not just based on one factor, and there is no definite formula to determine the cutting speed for each material has different characteristics. In determining the cutting speed are mostly done empirically. Factor in determining the closest cutting speed most easily seen from the tensile stress a material or by looking at two or all of the above factors. For example, the material is soft, brittle and low tensile has a higher cutting speed than the material more brittle and hard but its high Tensile.



Below is a table cutting speed of several types of material for HSS cutting tools

Based cutting speed shown, equation for calculating spindle speed of milling machine

 
Note:

n = spindle revolution (rev / min)
D = Diameter of the milling cutter (mm)
CS = Cutting Speed ​​(m / min)

Note:

For milling of carbide cutter Cutting Speed ​​= 2 x CS HSS Cutter 
For Twist Drill, NC Drill etc. Cutting Speed ​​= 0.5 x CS HSS Cutter 
For Countersink, Reamer etc. Cutting Speed ​​= 0:25 x CS HSS Cutter 
Boring head according by the cutting tool material.

Feeding in the milling process is the distance in one minute feeding in the count of the amount of feed per tooth (SZ or fz) multiplied by the number of teeth and the  milling cutter revolution in a minute.

equation by :
 
Note:

s = feeding (mm / min)
sz = feed per tooth (mm / tooth)
z = number of teeth
n = revolution of spindle (rev / min)

Table feed per tooth in millimeters
Note: that value are the maximum

Example Problem.

Known material of Stainless Steel 304 will be cut with a HSS End Mill Cutter with a diameter of 20 mm and the number of teeth = 4 pieces. calculate the spindle revolution and feeding!

note:

CS = 18 m / minute (taken from the table cutting speed for the material stainless steel 304)

sz = 0.05 mm / tooth (taken from table feed per tooth)

D = 20 mm

Answer:

n = 1000. CS / π. D

n = 1000. 18 / π. 20

n = 286.4 rpm

so the spindle revolution is 286.4 rpm, because the machine revolution table are 250 and 300 rpm were used was 250 rpm (the approach taken down).

s = sz. z. n

s = 0.05. 4. 286.7

s = 57.29 mm / min

so the feeding is 57.29 mm / min, meaning the milling cutter moves along the workpiece is 57.29 mm in one minute. the machines feed table are 56 and 63 mm / min, then used was 56 mm / min