How to calculate speed and feed?

Each tool adopts different processing parameters for different processing materials. In the field of milling, tool manufacturers develop more targeted coating technologies by optimizing tool materials to improve machining efficiency.

Through the combination of various elements in the material, we can see thousands of raw materials that can be processed. To process these materials, we must know the processing performance of this material and know how to optimize the processing.

The material group to which the workpiece belongs


According to ISO 531: 1966 International Standard

A total of processable materials are divided into 6 categories

they are, respectively:

P: the steel material represented;

M: the stainless steel material represented;

K: the cast iron material represented;

N: the non-metallic materials represented;

S: the high-temperature material represented;

H: the high-hardness material represented;

According to the tensile strength and hardness of the material, tool manufacturers classify materials in smaller categories in these categories. If we cannot find the processing performance parameters of the materials to be processed in these small categories, the most feasible way is to consult the tool supplier, I believe they are happy to help you solve this problem.

Calculation formula

We usually see the following formula in the tool manual


Before talking about this formula, let’s think back to the formula we have learned about the circumference of a circle:

 C (Circumference)=π (Circumference Rate)*d (Diameter)

According to this formula, we can conclude that for a tool with a diameter of D, the distance traveled by the outermost point of the tool for each revolution is:

π *D

Then, when the tool rotates at a frequency of n revolutions / 1 minute, the distance traveled is:

n*π *D

According to the formula of time (T) × speed (V) = distance (S), the speed Vc of the outermost point of the tool at any point in this period of time is:

Vc=(n*π *D)/1


 The following formula is obtained by conversion:

n=Vc/(π *D)

Note! Our tool uses millimeter (MM) as the unit, so the unit of speed Vc in the previous formula is: mm/min

After length conversion (1m=1000mm), we have this common formula:


After simplifying the equation, we have our final version of the formula:



Here, the unit of D (tool diameter) is still MM (millimeters), and the unit of Vc (line speed) has become: M/min (meters per minute)

This formula is also applicable to turning processing, in turning, but here D represents the diameter of the blank.


Post time: Mar-25-2021