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Active Contributor
rmathan
Posts: 35
Registered: ‎02-17-2011

How the moldflow software calculates Warpage?

1122 Views, 8 Replies
03-06-2012 10:18 PM

Dear All,

 

Could someone explain me how the moldflow software calculates the warpage and also how it correlates with the original part dimension?

 

 

Regards,

Mathankumar. R

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Active Contributor
rmathan
Posts: 35
Registered: ‎02-17-2011

Re: How the moldflow software calculates Warpage?

03-08-2012 09:08 PM in reply to: rmathan

Dear All,

 

I am facing warpage problem in the part around 30mm. Does anybody know basic behind the warpage predictions in moldflow software? where can we find the theory material?

 

 

Regards,

Mathankumar. R

 

 

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Valued Contributor
Posts: 82
Registered: ‎08-05-2009

Re: How the moldflow software calculates Warpage?

03-09-2012 08:26 AM in reply to: rmathan

I dont know how is someone going to answer this but i'd recommend going to through "help". It should give you a good amount information. Thereafter, you can be more specific about the question.

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Active Contributor
rmathan
Posts: 35
Registered: ‎02-17-2011

Re: How the moldflow software calculates Warpage?

03-09-2012 09:42 PM in reply to: nishit78

Thank you for your reply. I gone through the help. I don't understand the theory.

 

I have changed the product design around the part rib thickness. Now the Warpage is so much reduced from 30 mm to 8 mm.

 

But there is another concern arised. whatever the deflection values I got from dual domain mesh is entirely different  compare with 3D  warp analysis.

 

Deflection values comparision Dual domain mesh vs 3D mesh:

 

Dual Domain mesh: Deflection all effects: 0.98 mm to 7.93 mm

3D mesh:                 Deflection all effects: 2.87 mm to 33.46 mm

 

Could someone help me how to judge? Which results will be reliable?

 

Regards,

Mathankumar. R

 

 

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Valued Contributor
Posts: 55
Registered: ‎07-07-2009

Re: How the moldflow software calculates Warpage?

04-10-2012 02:01 PM in reply to: rmathan

It will be close to impossible to help you learn how to judge your models if you don't understand the theory behind it.

 

Make sure to go through the tutorials or injection molding books and understand why your warpage went down from 30 to 8mm first.

 

good luck!

 

Hugo Herrera

 

 

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Member
Posts: 4
Registered: ‎02-09-2010

Re: How the moldflow software calculates Warpage?

05-24-2012 07:12 AM in reply to: HugoHerrera7042

Hey Hugo,

 

I've asked this question directly to Moldflow before, and they've always gotten very quiet.  I suspect they're concerned that a rival program will try to copy them?  Anyway, here's what I've put together so far though, perhaps it will help.

 

The first thing you need to know is that the Fusion mesh & 3D mesh calculate warpage using different properties.  So it's very typical for the two of them to generate different results. 

 

The Fusion model still works on 2D theory.  It calculates the warpage based on shrinkage properties, then it applies a set of correction factors known as CRIMS.  If you want to use the Fusion results, I strongly recommend you check your material properties, and see if CRIMS data is even available (shrinkage tab).  As I understand it, the CRIMS adjustments reduce the predicted warpage, so if that data hasn't been generated, then it might explain why you're seeing really high values in your Fusion mesh.

 

I'm fairly certain the 3D mesh uses a completely different method to determine warpage.  Instead of looking at the shrinkage properties & using the CRIMS adjustements, it instead uses stress/strain curves & thermal expansion values (shown on the mechanicals tab of the material properties).  For what it's worth, I've found the that the 3D results are generally more accurate for our parts.  However, be aware that the 3D mesh can't capture complex warpage behaviors like buckling (for example, a flat plate where the sides shrink more than the center, causing the part to curl to relieve stress). 

 

Hope that helps a bit.

-Chris

 

 

 

 

 

 

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Board Manager
raalteh
Posts: 232
Registered: ‎04-14-2009

Re: How the Moldflow software calculates Warpage?

05-31-2012 08:31 AM in reply to: chris.nelson

Hi Chris,

 

To your comment 'However, be aware that the 3D mesh can't capture complex warpage behaviors like buckling...'

 

In the 2012 release non-linear warpage was introduced as an option. The default is still linear shrinkage, but a large deflection analysis should be able to produce a buckled shape. 

Hanno van Raalte,

Product Manager for Autodesk Simulation Moldflow products
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Member
Posts: 4
Registered: ‎02-09-2010

Re: How the moldflow software calculates Warpage?

06-29-2012 10:21 AM in reply to: rmathan

Hanno,

 

Are you sure about non-linear solvers being available for warpage studies in 2012?  I'm looking at the warpage settings tab right now, and I don't see a non-linear option, or even an option to change it.  If I change to a midplane mesh, then I the option appears, but not for a Fusion or 3D model.

 

-Chris

 

 

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Board Manager
raalteh
Posts: 232
Registered: ‎04-14-2009

Re: How the moldflow software calculates Warpage?

06-29-2012 11:01 AM in reply to: chris.nelson

Hi Chris,

 

I'm absolutely sure :-), but I have to admit that it's a little hidden.

 

Follow these steps:

1) Go to the process settings wizard and go to the 'Warpage Settings' page.

2) uncheck the option "use mesh aggregation and 2nd order tetrahedral elements'

3) Doing this will make an 'Advanced options' button visibile (the non-linear option cannot be used in combination with the default mesh aggregation option)

4) click ton the 'Advanced options' button and you will see the dialogue box below. You can swith 'Small deflection to 'large deflection.

 

advanced_options.JPG

 

Hanno van Raalte,

Product Manager for Autodesk Simulation Moldflow products
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