**SPINDLE SPEED [N] :**** **Spindle speed plays a very important role in calculating cutting speed. Spindle speed is also called RPM. This means how much revolution the spindle does in a minute is called RPM or spindle speed.

Suppose 2000 spindle speed. If you want to show spindle speed in a CNC program, it should be called **S2000**.

**CUTTING SPEED:**** **It is the speed at which material remove in one minute by cutting tool from a linear distance of workpiece. It is express as **mm/min** or **m/min.**

** Formula ;**

** Cutting speed (Vc)= (π D1 N)/1000 ****mm/min**

Where D1 = Uncut diameter of the workpiece

N = Spindle speed

Sometimes tool have cutting speed limitation . Consider limitation of tool for cutting speed Vc 200 to 250 and diameter D is 50. That time we need to calculate spindle speed

Let’s see the calculation ;

**200 =** **(3.14 ×50×N)/1000 **

**N = 1274 RPM**

**FEED: **It is simply defined as a movement of cutting tool each cut . It is express as mm/rev.

**DEPTH OF CUT :**** **Thickness of metal removed in each cut of the tool . It is a perpendicular distance measure from the machined surface to the uncut surface of a workpiece .

Depth of cut calculation while performing turning

** **

** d =**** (D1-D2)/2**