Enter the perimeter of the punch, the thickness of the material, and the shear strength of the material to calculate the punching force.

## Punching Force Formula

The following formula is used to calculate a necessary punching force.

PF = P * T * SS
• Where PF is the punching force (kN)
• T is the thickness of the material (mm)
• P is the perimitter of the die or punch (mm)
• SS is the shear strength (kN/mm^2)

The units can be switched as long as the thickness and perimeter match up with the squared term in shear strength. For example, if the thickness and perimeter are in inches, then the shear strength must be in force per inch squared.

Common materials shear strength:

• Aluminum – .1724 kN/mm^2
• Brass – .2412 kN/mm^2
• Carbon Steel – .3447 kN/mm^2
• Stainless Steel – .5171 kN/mm^2

## Punching Force Definition

A punching force is defined as the total force required by a punching press to successfully cut or punch through a certain material.

## Example Problem

how to calculate punching force?

First, determine the perimeter of the die. For this example, the press has a simple circular die with a perimeter of 40mm.

Next, determine the thickness of the material. For this example, the material being punched is 3mm thick aluminum.

Next, determine the shear strength of the aluminum. Aluminum is known to have a shear strength of .1724 kN/mm^2.

Finally, calculate the punch force.

Using the formula above:

PF = P * T * SS

= 40*3*.1724

= 20.688 kN

= 20,688 N.