how to calculate the clamping force simply

Generally, when we see a simple product, we can try to calculate the needed clamping force of the injection molding machine simply like below:

Clamping force=common constant for clamping force calculation * vertical projection area of product on the mold platen

F=KS

F-clamping force of injection molding machine, ton

S-vertical projection area of product on the mold platen, cm2

K-common constant of different plastic material, ton/cm2

Below is the table of the common constant of different plastic material