Please find below the formula to calculate punching forces.
F = punch force in Kilonewton
(10 kN = 1 metric ton)
U = circumference or perimeter of the punch shape (in mm)
s = Sheet thickness (in mm)
Rm = tensile strength (in N/mm²)
for Stainless Steel (1.4301) 720 N/mm²
for Mild Steel (St 37) 420 N/mm²
for Aluminium (AlMg3) 220 N/mm²
f = factor between 0,5 - 0,95 when using punches with shear.
Note:
Metric units are shown above, however a modified formula can be used for other units of measure (such as inch); keep in mind that all the units of measure must be the same
throughout the formulas (all in inches, all metric, etc.)
Punching Force =
punch perimeter x material thickness x material shear strength x f (shear factor)
- punch force (tons)
- punch perimeter (inches)
- material thickness (inches)
- material shear strength (tons per square inch)
