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Simulation Moldflow Insight

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Valued Contributor
PascalGosset
Posts: 71
Registered: ‎06-18-2010

Re: Tips and tricks to improve the pressure predictions.

11-16-2011 12:00 PM in reply to: sadashiv

Sorry everybody…
No news from Moldflow for the moment…
Waiting them, I propose you to take a look at my survey results.
See the picture joined.

 

Reading it, I notice a lot of you take into account the runners.
Personally, I have doubts about them since a long time.
And now, I think they can lead to underestimated pressures bigger than 100 %.
(even with runners perfectly design, all meshes, all materials… )

 

For the moment, I advise you to make your simulations without the feeding.
To consider the pressure lost in the hot runners system, ask your supplier.
But, check he does not gives you values got with simulations.

 

"Maybe Moldflow does not work properly, but the real world neither."
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Member
csegard
Posts: 6
Registered: ‎02-18-2010

Re: Tips and tricks to improve the pressure predictions.

11-25-2011 07:42 AM in reply to: PascalGosset

Hello M. Gosset,

 

just to present myself for others, i am working for the moldflow reseller in France and deal with the case for M. Gosset.

 

I am really surprised to see that, for you, there is no answer from Autodesk.

From my side and from Autodesk side, we give some advices on materials datas to check and on modelization to have better results on Pressure.

 

Autodesk and I will be really pleased to discuss with you directly during a meeting in your office.

 

Regards

 

Cédric

 

 

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Valued Contributor
PascalGosset
Posts: 71
Registered: ‎06-18-2010

Re: Tips and tricks to improve the pressure predictions.

11-27-2011 02:12 AM in reply to: csegard

Hello Cédric,

 

It’s true that you worked on my case.
But you did not look in the sense I was expecting for.
That is why, few days ago, I explained you clearly what I made by my side.
I told you my tracks, my clues and my conclusions.
For the moment, it seems we do not agree.
I think I have to work more on this subject.
But I hope, by your side, you are going to take my hypotheses more carefully.

 

Best regards.

"Maybe Moldflow does not work properly, but the real world neither."
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Valued Contributor
HugoHerrera7042
Posts: 62
Registered: ‎07-07-2009

Re: Tips and tricks to improve the pressure predictions.

04-10-2012 02:40 PM in reply to: PascalGosset

Sounds interesting.

looking fwd to your input

 

whereas moldflow does not include pressure losses at the screw and barrel, i wonder what were your 'tricks' to have a significant closer correlation on your models.

 

feeding system - meshing quality perhaps?

 

 

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Member
nwvanvliet
Posts: 5
Registered: ‎04-11-2012

Re: Tips and tricks to improve the pressure predictions.

04-11-2012 09:50 AM in reply to: PascalGosset

Are the incorrect pressure plots done with a single beam element per segment?  

 

Then the correct one was done using multiple beam elements per segment, especially at the gating position?  

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Valued Contributor
PascalGosset
Posts: 71
Registered: ‎06-18-2010

Re: Tips and tricks to improve the pressure predictions.

04-12-2012 05:12 AM in reply to: nwvanvliet

I'm working on this subject since few months.

But I have not finished.

 

About my trick, I can tell you what it is. But, I don't know if it works always.

What I know is it worked for 3 parts I chose  by chance.

 

Take a look at the 1st curves in the picture 1.

The distance between them means there is an important under-estimation of the material compressibility in the runners (all : cold and hot, beam, 3D).

 

To correct this trouble, I only DOUBLE the length of ALL runners (using the tool Scale).

See the results picture 2.

 

In fact the problem comes from the compressibility factors included in the materials data.

The fields c1, c2 D3 are not filled for 80% of the database (see picture 3).

They are for materials certified "Gold".

That's why the pressure prediction is good in the 4th example of the picture 1.

 

"Maybe Moldflow does not work properly, but the real world neither."
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Member
nwvanvliet
Posts: 5
Registered: ‎04-11-2012

Re: Tips and tricks to improve the pressure predictions.

04-12-2012 09:17 AM in reply to: PascalGosset

I was under the impression that Moldflow's solver always assumes D3 is zero, regardless of what was input.

 

Here's a snippet from their wiki about C1 and C2 values...

http://wikihelp.autodesk.com/Moldflow/enu/2013/Help/2.0Insight/4441-Material4441/4995-Juncture4995

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