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Member
jl2911
Posts: 3
Registered: ‎09-04-2012

Abnormal heat loss on 3D gate

477 Views, 4 Replies
09-04-2012 08:46 PM

Hi all,

 

I came across a phenomenon while using 3D mesh to do fill + pack simulation in moldflow that the heat loss near gate seem to be much greater than area away from gate and caused early gate froze.

 

To demonstrate this easily, a flat square plate (2mm) with direct gate (dia 2mm) is model in 3D.

  

Refer to the picture:

At end of fill (top), I will get higher temperate toward gate direction, which make sense to me.

But during pack period (middle and bottom), it actually cool down much faster near the gate, which is weird, as this simulation only concentrated on fill + pack, the mold temperature is homogenous. Thus the heat loss should be quite identical given a simple flat plate like this.

 

Has anyone come across this problem or know what is going on the heat loss equation near gate? As this actually causing quite different result for warpage between dual domain and 3D mesh, as the 3D gate froze faster than dual domain, thus less pack.

 

*Changing the gate to side gate, using beam element for gate, more layers for 3D mesh, and finer mesh are giving the same tendency.

* I am using moldflow insight 2013

 

regards,

jl

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Member
jl2911
Posts: 3
Registered: ‎09-04-2012

Re: Abnormal heat loss on 3D gate

10-03-2012 01:43 AM in reply to: jl2911

Hi,

Any help here? No one came across this issue? or just me that did something wrong in the setting?

 

regards,

Ling

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Active Member
ashwinkumarnr
Posts: 10
Registered: ‎03-27-2012

Re: Abnormal heat loss on 3D gate

01-03-2013 01:49 AM in reply to: jl2911

Hi,

The gate will cool first as it is of smallest cross section compared to the part. Isnt it .

 

 

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Member
jl2911
Posts: 3
Registered: ‎09-04-2012

Re: Abnormal heat loss on 3D gate

01-06-2013 11:04 PM in reply to: ashwinkumarnr

Hi ashwinkumarnr,

 

Thanks for the reply. Yes, the gate will cool first as smaller cross section. But my main concern is actually region near the gate. When refer to my attached picture, you will see that the 3D gate surrounding area will cool down much faster than other area. And this doesn't happens on dual domain simulation.

Any thought what are the causes?

 

regards,

jl

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*Expert Elite*
madhukeshwart
Posts: 323
Registered: ‎03-18-2009

Re: Abnormal heat loss on 3D gate

01-07-2013 06:00 AM in reply to: jl2911
yes, rate of cooling will be dependent on cross section and gate being smaller

and aslo such phenomenon is more predominant if it is crystalline..

and also it depends on shear rate / shear heating at gate region also.

lower shear rate at gate leads to faster gate cooling.

Regards,
Madhukeshwar Talwar
Madhukeshwar Talwar

FIAT-CHRYSLER ATC, Chennai
mail: madhukeshwart@gmail.com
09600060862
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