Use of Gate freeze time

[Sanjay_paul]

Hello everyone,

what is the implementation of gate freeze time? And  what is the effective way of finding it in Dual Domain analysis for both hot runner and cold runner mold?

Regards

sanjay paul

[Anonymous]

Hi @Sanjay_paul

You can use frozen layer fraction to identify the gate freeze time in analysis with DD mesh.

The Frozen layer fraction result is an intermediate result, which is animated through time by default.

The values of this result range from 0.0 to 1.0 . A higher value represents a thicker frozen layer, a higher flow resistance, and a thinner polymer melt or flow layer. A polymer is considered to be frozen when the temperature falls below the transition temperature.

Frozen-layer thickness has very significant effects on the flow resistance. The viscosity exponentially increases with decreasing temperature. The thickness of the flow layer is also reduced as the thickness of the frozen layer increases.

[mppkumar · Accepted solution]

Hi @Sanjay_paul

In case of DD mesh, suggest to check , Frozen layer fraction results (also you can check Time to reach ejection temperature plot)

In case of 3D mesh, suggest to use below method to identify gate freeze time

-Select 'Temperature' plot - and modify Plot properties - Methods tab - Contour - Single Contour - Contour value (Enter Material's Transition Temperature)

- change the Scaling as "Per frame" and animate the result, need to check the time when material flowing from gate to part is disconnected, that time will be the Gate freeze time

[mppkumar · Accepted solution]

Gate freeze time will decide your packing time

once gate freezes, beyond that if you specify the packing time... this won't help your part packing properly

assume, your gate freezes within 6sec and the packing time specified as 10sec, then effective packing will be happening for only 6sec, rest 4sec will only increase cycle time

[dramaswamy]

Thanks for this tip,. worked ; I was changing the Min temp as GDT in the result bar. Can you educate how to increase the resolution of frame intervals.  my case gate is freezing in between 2.5 to 4.75 second , could not find exact range , 2 seconds is a wider range

[bernor_mf]

@dramaswamy 

Hi,

the kind of jump you see in time is due to intermediate interval, which the are related to result frames.
For a 3D mesh type, the default intervals are:
Filling: 5
Packing: 5
Cooling: 3

To change for 3D Mesh type:
From Process settings wizard:
Advanced options...
Solver parameters ; Edit...
tab Fill+Pack analysis
Intermediate result ; Edit intervals...

Increase this interval value for more frames.
Minimum 10 of each I would say, but more if needed.

Increasing the value will increase the number of animation frames available when animating certain results through time, but will also increase the disk space requirements for the analysis.

To get the wished default settings when creating new studies:
tab Tools:
Click: Databases (with small arrow down).
Select: Edit Default Properties
Select: Thermoplastics injection molding solver parameters defaults (3D)
Change the settings as preferred for new studies.
Exit with OK.
Note: Updating Moldflow Synergy UI will reset settings to default.
Recording a macro of changes, that could be executed after update helps.

Hope this helps.

Regards,

Berndt