What Is The Calculation Formula For Cutting Speed | CNCLATHING


What is the calculation formula of cutting speed? How to calculate cutting speed? Read on this article and get to know formula to calculate cutting process.

Cutting Speed Formula

When machining a part or a component, the cutting speed formula is one of the most critical criteria to consider. It is possible to boost the material removal rates by using the proper cutting speed and feed, hence improving the surface finish and the tool’s lifetime. It is just as critical as developing a faultless CNC machining framework to ensure that the cutting speed and feed are set to exacting standards. A perfect machined workpiece cannot be manufactured unless this is done.


Selection Principle Of Cutting Parameters

In the process of CNC machining, the programmer must ensure the cutting parameters of each process and write them into the program in the form of instructions. Cutting parameters include cutting speed, back feed and feed rate. Different cutting parameters should be selected for different machining methods.

During rough machining, productivity is usually improved, but economy and processing cost should also be considered; When semi finishing and finishing, we should take into account the enthusiasm of cutting efficiency and machining cost on the premise of ensuring machining quality. The specific value shall be determined according to the NC machine tool manual, cutting parameter manual and experience.

Starting from the durability of NC tools, the selection order of cutting parameters is: first determine the back feed, then determine the feed, and finally determine the cutting speed.


Example 1: Cutting Speed Vc

The instantaneous speed of the selected point on the cutting edge relative to the main motion of the workpiece. The calculation formula is as follows:

Vc=( π d w n )/1000

Where Vc – cutting speed (m / min);

dw – diameter of workpiece surface to be machined (mm);

n – workpiece speed (r / min).

The calculation shall be subject to the maximum cutting speed. For example, during turning, the calculation shall be based on the value of the surface diameter to be machined, so the speed here is the highest and the NC tool wear is the fastest.


Example 2: Turning diameter is Φ The outer circle of 60mm workpiece, the selected lathe spindle speed is 600r / min, and VC

Solution: Vc = (π d w n) / 1000 = 3.14x60x600/1000 = 113 m / min

In actual production, the workpiece diameter is often known. The cutting speed is selected according to the workpiece material, tool material and processing requirements, and then the cutting speed is converted into the spindle speed of the lathe to facilitate the adjustment of the lathe. The following formula is obtained:

n=( 1000v c)/ πd w


Example 3: Turning on CA6140 horizontal lathe Φ For the outer circle of 260mm pulley, select Vc as 90m / min and find n.

Solution: n = (1000Vc ) / π d w = (1000×90) / (3.14×260) = 110R / min

After calculating the lathe spindle speed, the value close to that on the nameplate shall be selected, that is, n = 100r / min shall be selected as the actual speed of the lathe.


Cutting speed Vc (m / min) Vc = Πdn / 1000 (m / min)



The figures obtained from the calculations are for reference only. The conditions for machining depend on the machine tool you are using. Use the optimal conditions according to your actual machining circumstances.