Moldflow LSR with gravity

[r_weissQ6ZVD]

We're having a LSR tool with coldrunner-system.

It's a 2 cavity tool (above eachother) in a vertical state.

We did many tests and tried many settings, but the weight of the parts always varied over the hours.

Weight of the 2 cavities over 15 hours.

We then mounted the tool in a horizontal way and this improved the balance much more.

(no other settings/parameters were changed)

We are missing the theory behind this.

And we would like to run a Moldflow on this problem. Is this possible?

Run it in a vertical state and horizontal state to see how much gravity  is of any influence. 

[bernor_mf]

@r_weissQ6ZVD 

Hi,

Welcome to the Moldflow forum! 😊

First, in general when molding thin walled parts, viscosity is usually low and flow of polymer is fast into the mold cavity.
Therefore, the effect of gravity on the molding process is not a significant factor in the molding process.

But gravity effect on mold filling could be experienced, and Moldflow Insight can simulate the effect. 

Thicker parts and slower injection speed, the effect could significant, as well as mold position in Injection Molding Machine.

Yes, you could run a mold filling simulation using Moldflow Insight to simulate the gravity effect.

Gravity can be considered in a 3D tetra mesh type, and 3D Fill+Pack analysis sequence.

Some useful links:

Moldflow Insight 2015 Help: Gravity direction

Moldflow Insight Help | To specify the gravity direction | Autodesk

Understanding the Gravity of the Situation Beaumont Technologies, Inc.

Hope this helps.

Regards,

Berndt

[mason.myers]

Hello @r_weissQ6ZVD ,

What is the cure time?  Are you using a solidifying or non-solidifying runner? Sometimes the runner layout can cause shear imbalances but would not cause variations in weight during the cycle.

Mason

[r_weissQ6ZVD]

It's a relative thick walled product, around 5mm, with an injection time of around the 5,5 sec ( 60cm³) (for both products).

And it's an cooled runner system (colddeck/coldrunner), so non-solidifying?

Curing time is 25 seconds.