How to Calculate CNC Speed and Feed
Each tool will adopt 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 processing efficiency.
Through the combination of various elements in the material, we can see thousands of machinable raw materials. To process these materials, we must know the processing performance of this material, and also know the method that should be optimized for processing.
01 The material group to which the machining workpiece belongs
According to the ISO 531:1966 international standard, the machinable materials are divided into 6 categories, which are:
The steel material represented by P;
Stainless steel material represented by M;
The cast iron material represented by K;
Non-metallic materials represented by N;
High temperature material represented by S;
High hardness material represented by H;
Within these broad categories, tool manufacturers divide materials into smaller categories based on their tensile strength and hardness.
02
Calculation formula
We usually see the following formula in tool manuals
Before talking about this formula, let’s recall what we have learned about the circumference formula of a circle:
C (circumference) = π (pi) * 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 per revolution is:
π *D
Then, when the tool rotates at the 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 time point during this period is:
Vc=(n*π*D)/1
By conversion, the following formula is obtained:
n=Vc/(π *D)
Notice! 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 simplification of the equation, we have our final formula:
Notice!
Here the unit of D (tool diameter) is still mm (millimeter), and the unit of Vc (linear speed) becomes: M/min (meter/minute)
This formula is also applicable to turning, in turning, except that D here represents the diameter of the blank.
