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## Simulation Moldflow Insight

Contributor
Posts: 15
Registered: ‎06-03-2011

# Convergency problems at inlet node

1816 Views, 7 Replies
02-27-2013 05:52 AM

I have been running a complete Cool + Fill + Pack + Warp analysis, but i goes into several iterations and in every one of them, the next message follows decrement:

** WARNING 700990 ** Solution iteration limit reached before convergence
Solution error = 1.0000 C
| 1| 80.000| 0| 1.000000| 0| 0.000000| 1.000000|
+----------+----------+----------+----------+----------+----------+----------+

** WARNING 700530 ** Problem encountered in circuit with inlet node 129.
The continuity equation has not converged.

What can be wrong with that node???? any suggestions?

Several times during checking of the model, the next warning message appeared:

** WARNING 701360 ** Beam element X has a very bad length/diameter ratio

Diameter of hoses is 14.29 and lengt of beams is ~ 10 mm, could be that the main problem?

Product Support
Posts: 475
Registered: ‎03-23-2009

# Re: Convergency problems at inlet node

02-28-2013 01:26 AM in reply to: kgonzal5

Hi,
seems as the L/D ratio for cooling channel might be the issue here.
A length/diameter ratio of 2.5 to 3 is recommended for cooling channel beams.
For example, the Global edge length when meshing should be between 25–30 mm for a channel that has a diameter of 10 mm.
For a cooling circuit with Diameter of 14.29 mm, the Length should be about 35 - 43 mm.

See wikihelp:
http://wikihelp.autodesk.com/Simulation_Moldflow/enu/2013/Help/2.0Insight/0670-Modeling670/1431-Cool...

Hope this helps.

Regards,
Berndt

Berndt Nordh
Employee
Posts: 119
Registered: ‎04-28-2009

# Re: Convergency problems at inlet node

02-28-2013 07:47 AM in reply to: nordhb

Problem can also be due to :

- Overlaped elements

- Branching circuits : If you circuits divide after in several circuits

Maybe check your circuits design, and simplify a bit the branching if exists.

Contributor
Posts: 15
Registered: ‎06-03-2011

# Re: Convergency problems at inlet node

02-28-2013 12:56 PM in reply to: nordhb

Thank you for the advance, I took both, changing mesh of the beams to a 38 length, and deleting branching nodes,  but still there are many warnings regarding ratio, and I remeshed to 38 mm.

Right now it has started without any problem showed at the inlet node , but iteration is taking so long, and still I can´t see change in iteration.

External |Cycle time|Avg temp |Avg temp |Dif temp |Dif temp |Circ temp |
|iteration | (s) |iteration |deviation |iteration |deviation |residual |
+----------+----------+----------+----------+----------+----------+----------+

| 1| 110.000| 2| 1.000000| 0| 0.000000| 1.000000|
| 1| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 1| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 1| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 1| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 1| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 1| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 1| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 1| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 1| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 1| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 1| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 1| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 1| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|

** WARNING 700990 ** Solution iteration limit reached before convergence
Solution error = 1.0000 C
| 1| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
+----------+----------+----------+----------+----------+----------+----------+

** WARNING 700490 ** Problem encountered in circuit with inlet node 27.
The energy equation has not converged.
Convergence residual = -1.00000E+00
| 2| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|

As I remember in other analysis, this just don't seems good... Let you know if for tomorrow this status has changed

Product Support
Posts: 475
Registered: ‎03-23-2009

# Re: Convergency problems at inlet node

03-04-2013 12:56 AM in reply to: kgonzal5

Hi,

when you see warnings after remeshing cooling circuits, the warning is probably realted to runner beams mesh.
The runners can have finer mesh, but cool solver will give the L/D warning.
This is often no problem, and you look at temperature results to confirm result is fine.

Did you model mold surfaces ?
Sometimes you can run in to convergence issues, and then creating a meshed mold block will make the analysis converge as improving the accuracy of a Cool analysis.
In Synergy, Home and click Geometry, use Mold Surface to create and mesh a mold block.
Then rerun analysis.

Regards,

Berndt

Berndt Nordh
Contributor
Posts: 15
Registered: ‎06-03-2011

# Re: Convergency problems at inlet node

03-04-2013 06:39 AM in reply to: nordhb

Yes, I have already created the mold surface and I have drawn again all the cooling lines, ensuring that I have sequence on the beams, but it seems not working at all, since after third iteration, the analysis crashes and sends always the same message

** WARNING 700490 ** Problem encountered in circuit with inlet node 27.
The energy equation has not converged.
Convergence residual = -1.00000E+00
| 3| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 3| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 3| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 3| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 3| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 3| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 3| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 3| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 3| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 3| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 3| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 3| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 3| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|
| 3| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|

** WARNING 700990 ** Solution iteration limit reached before convergence
Solution error = 1.0000 C
| 3| 110.000| 0| 1.000000| 0| 0.000000| 1.000000|

** ERROR 701010 ** Cool analysis has not converged.
+----------+----------+----------+----------+----------+----------+----------+

** WARNING 700490 ** Problem encountered in circuit with inlet node 27.
The energy equation has not converged.
Convergence residual = -1.00000E+00

** WARNING 98000 ** The following warning messages occurred more than 5 times:

Message No. Number of occurrences
701360 50

Contributor
Posts: 15
Registered: ‎06-03-2011

# Re: Convergency problems at inlet node

03-04-2013 08:54 AM in reply to: kgonzal5

There is one more thing, when checking connectivity everthing is OK, but when performing Cooling Circuit Diagnostic, the message “No elements were found for the diagnostic” appears.

Product Support
Posts: 475
Registered: ‎03-23-2009

# Re: Convergency problems at inlet node

03-05-2013 12:11 AM in reply to: kgonzal5

Hi,

need to have a look at the study.

Will contact you directly.

Regards,

Berndt

Berndt Nordh