Clamp force increasing after V/P switchover

[nguyenbuulam]

Hi Moldflow supporter, and engineer
I am Moldflow user.
I would like to inquire your support about result of moldflow simulation.
The calculated maximum clamp force is a function of injection pressure and the projected area of the part.
So I don't know: after V/P switchover, pressure is low down, but clamp force is increased (see below picture to get details)
Could you tell me why it is?

Thank you in advance for your support.

[jh_lee · Accepted solution]

@nguyenbuulam 

It can be easily seen by looking at the pressure results.
Check the pressure results at the point where the clamping force is the highest.
When the velocity/pressure switch-over point is 98% of the volume, the maximum injection pressure is high, but the overall internal pressure of the product is not high.
However, when it is 100% of the volume, the internal pressure of the product increases.

[nguyenbuulam · Accepted solution]

Hi  jh.lee
Thank you for your support.

[PascalGosset · Accepted solution]

Hello simulators,

At the switchover, the pressure is high in the sprue but it is zero in the end of the cavity.

So the average pressure in the cavity is quite the half of the pressure in the sprue.

After the switchover, the material fills all the cavity and it is so compressed that there is a only weak

difference between the pressures in the sprue and in the part end.

That's why generally, the maximum clamp force is reached just after the switchover.

[nguyenbuulam]

Hi Mr Pascal Gosset
Thank you for your expertise comment.
By the way, I am impressive with slogan from your signature: "Maybe Moldflow does not work properly, but the real world neither" my son...6 years old.