Adding a parallel runner

[Anonymous]

Hi everyone,

i've been trying to design a mold with a film gate and a parallel runner, as shown here:

What I haven't been able to do is to ad a parallel runner. Any advices on how to do this? 

thank you!

Bermet 

[bernor_mf · Accepted solution]

Hi Bermet,

welcome to the forum. 

The runner you show is difficult to do in Moldflow Adviser.

1) You could model the film gate and parallel runner in CAD as part of cavity, to get a "clean" injection location

for injection location to model small runner and sprue.

The problem with this is that film gate and parallel runner belongs to part, and included in warp simulation.

(If beams, they are disconnected at ejection, for warp analysis.)

The thick parallel circular runner will shrink more and affect the deflection of part.

But a workaround, if you need to understand about process, without considering warp.

2) Another idea is to place many injection locations close at edge, and make tab gates.

Then connect with parallel runner.

The problem with this is each tab gate will have a separate flow in to cavity.

So a divided, branched flow in to cavity.

Maybe not so useful, as divided flow like this might give other effects.

The runners will not belong to cavity/part though.

3) Move to Moldflow Insight

Has more modelling options to create this kind of runner layout.

Hope this helps somewhat.

Regards,

Berndt

[Anonymous]

Hi,

thank you!

I actually need to study the orientation of fibers in a simple flat plate, my material is polypropylene with short fibers. I think the first option seems more suitable, but trying to run the analysis I see that the orientation is not close to what we obtain in reality.

Do you think that the problem arises from the fact that the runner and gate are modeled as part of the cavity? In this case, the only solution would be moving to Insight? 

Thanks again!

Bermet 

[bernor_mf]

Hi Bermet,

do you run as Dual-Domain or 3D ?

As a circular runner to film gate, 3D captures the chunky area better.

Dual-Domain try to match triangles and assign thickness, so not so good representation of real runner.

Also, in Process Settings, tab Accuracy (a bit hidden - use right arrow to get there) you can increase Analysis model processing resolution. Level 0 (standard). Each level increase number of elements (finer mesh), and for 3D more tetra

layers in thickness direction. Higher resolutions requires more resources, and takes longer to compute as more elements.

Do a test of higher level, to see if results improve.

Is the mold already designed with such a runner?

Assume this is an ISO standard test plaque.

Many times those kind of test plaques has a fan gate.

The Fiber orientation tensor plot you display, is Normalized thickness 1.

This means on surface.

Animating this:

- Normalized thickness 1, surface A

- Normalized thickness 0, middle

- Normalized thickness -1, surface B

Then you have the Average fiber orientation, over time. (for Dual-Domain).

3D has Fiber orientation tensor plot on elements through thickness.

So it also depends on how you compare your real test plaque with results.

Moldflow Insight also has more options to review fiber orientation results.

Have a look in online help for more information: Fiber orientation analysis

Regards,

Berndt

[Anonymous]

Hi Berndt,

thank you for your inputs. I've tried to run both in 2D and 3D with more or less similar results. 

I'm using these result from a paper as reference. It is expected that using a film gate orientation of fibers on the surface is in the direction of injection and in the middle fibers are less oriented (left image is the surface and right - middle).

Modeling a similar plate with similar size, I'm not able to obtain the same results. I'm using the default injection parameters

Do you think the problem arises from the limitations of Moldflow Adviser since runner is a part of the cavity. Or could it be that the analysis is performed wrong? 

thank you/ 

Bermet

[bernor_mf]

Hi Bermet,
thank you for the update.

Moldflow QA does validation of fiber orientation, and also different models.

The fiber orientation models and solvers has improved over the years.

Seems as the pictures from paper uses 3D mesh type.
Does the paper mention Moldflow Insight?
If they have used Moldflow Insight, they can use different fiber orientation models
and also tweak parameters.
So result could then be a limitation due to Moldflow Adviser.

Are same material data, process settings used in simulation as in paper?

The thick runner dimension to film gate points to use 3D mesh type.

Did you try higher accuracy level? (increased level: more elements in model, om surface and through thickness if 3D)

Maybe Autodesk Tech Support should look in to this?
(Provide paper, models, material data, process settings, for further investigation.)

To me it is not a clear cut for the moment, why you experience the difference.

Regards,

Berndt