Calculating Clamping Force

[processtech]

Hello,
As a means to estimate the required clamping force for a mould, i am working out the approximate area of the parts, and then getting force by multiplying a pressure by the area. This is where i get stuck, how does one know the recomended cavity pressure for the material being moulded. I cant see it on manufacturers spec. Its a LLDPE material. Thanks for any advice given

[Suhas]

It is not a easy number to get or even guess. Thin parts need more pressure to fill but think parts need pressure to get packed out. To be on the safe side, I would use 4 or 5 tons/ sq in.
Hope this helps.
thanks.
Suhas

[processtech]

It is not a easy number to get or even guess. Thin parts need more pressure to fill but think parts need pressure to get packed out. To be on the safe side, I would use 4 or 5 tons/ sq in.
Hope this helps.
thanks.
Suhas
Thanks for your reply

[RocketOtter]

I agree with that guy. 4-5 ton/in² will usually keep you safe. If the cavity is over 1" deep from parting line it can add to the required tonnage. LLDPE usually has a pretty low MFR which usually requires higher pressures so I would definitely stay toward the 5 ton/in² side.