MAYDOWN FORMULAE FOR MILLING CALCULATIONS

Key for formulae:
	D = Diameter of cutter	T = Number of teeth	rpm = Revolutions per minute
	F = Cutter feed (or table traverse)	FT = Feed per tooth	S = Peripheral speed of cutter
	π = 3.1416	HP = Motor horsepower	C= Machinability constant

TO CALCULATE CUTTER SPEED S (ft / min) =     D x π x rpm     = 0.2618 D x rpm 12       S (m / min) =     D x π x rpm      1000

TO CALCULATE FEED PER TOOTH       FT =    F   T x rpm

TO CALCULATE CUTTER REVOLUTION           rpm =     S (ft / min) or S (m / min) x 1000   0.2618 D D x π

TO CALCULATE CUTTER FEED (TABLE TRAVERSE)               F = FT x T x rpm

HORSEPOWER HP
Power requirements:
Horsepower required can be calculated using the following formula which is based on a metal removal rate of one cubic inch per minute per horsepower. The machinability constant 'C' allows 25% for cutter dulling and 60% power efficiency at the cutter spindle.
HP =	Depth of cut x width of cut x T x FT x rpm	=	Depth of cut x width of cut x F
	C		C
Kilowatts = HP x 1.34
Machinability Constant 'C' =    Aluminium and soft alloys = 4.0,    Grey cast iron = 1.5,    Steel up to 300 HB = 0.6,    Steel up to 400HB = 0.5,    Brass (duplex) = 2.5,    Low Carbon steel = 1.0,    Bronze = 2.0

TO CALCULATE AVERAGE CHIP THICKNESS              = Feed per tooth x √ cutting width   cutting diameter

TO CALCULATE METAL REMOVAL (cubic)               = Feed x depth of cut x width of cut

G9 Previous Page Next Page