# What is the force required to puncture through a sheet of foil against an anvil?

A hardened steel contour with a sharp edge presses against plastic foil which lies on top of a hardened steel anvil plate. What would be the force required to punch through the foil?

I am familiar with the general punching/blanking formula, however, as far as I know this only applies to punching into a die i.e. the countour goes fully through the sheet. A picture is added to further clearify the question.

General blanking formula: $$$$F = K*l*t*\tau$$$$

where $$K$$ is a material/safety factor, $$l$$ the circomference of the contour, $$t$$ the sheet thickness and $$\tau$$ the shear stress.

• So, you say the hardened steel tool has to go through the plastic and you state the formula is for a tool to go through material. Then why do you think it is not relevant? Commented Sep 7, 2022 at 13:42
• The formula is for full puncturing. In this case the contour cannot fully pass through the foil. It can only press against a bottom anvil with the foil in between. I can imagine this might not match the given formula but I'm more than happy to be told otherwise. Commented Sep 7, 2022 at 14:17