Cutting speed for drill

 Cutting speed and rpm for drilling machine

. define cutting speed

. state the factors for determining the cutting speed

. ddifferentiate between cutting speed and rpm

. determine rpm/spindle speed

. rpm for drill sizes

For a drill to give a satisfactory performance, it must operate at the correct cutting speed and feed. Cutting speed is the speed at which the edge passes over the materials while cutting, and is expressed in metres per minut.cutting speed is also sometimes stated  as surface speed or peripheral speed. The section of the recommended cutting speed for drilliing depends on the materials to be drilled, and the tool material. Tool manufacturer's usually provide a table of cutting speeds required for different materials. The recommended cutting speeds for different materials. Based on the cutting speed recommended, the RPM, at which a drill has to be driven, is determined.

 Materials being         cutting speed(m/min)

Drilled for HSS

Aluminum                       70-100

Brass                                  35-50

Cast iron(grey)                 25-40

Copper                              35-45

Steel                                    20-30

How to calculating RPM

V=n×d×3.14/1000 m/min

n=v×1000/d×3.14

n=RPM

V=cutting speed in m/min

d=diameter of the drill in mm

It is always preferable to set the spindle speed to the nearest available lower range. The selected spindle speed is 300RPM. The RPM will differ according to the diameter of the drills. The cutting speed being the same, larger diameter drills will have lesser RPM and smaller diameter drills will have higher RPM. The recommended cutting speed are archived only by actual experiments.