Moldflow analysis warpage results

[feaplastic]

Hello Forum users,

we have a problem of warpage with one big plastic (PP 30% glass filled) component like all plastic products. we did the moldflow analysis and got warpage results. Cooling is also considered during the analysis.

Warpage says 0 to 24 mm. But Moldflow engineer says(other company) it is not 24 mm, Just relative units. So, it means we cant get howmuch mm it will warp. Is it mm or just units?

How to read the results. Is it possible to implement results in the read mold. What is your experience.

Thanks for any help.

 

[patprimmer]

In my experience, Mouldflow still has some way to go in predicting warpage in glass filled semi crystalline materials like pp.

Can you post drawings or cad models. I have about 30 years experience in attempting to predict warpage in similar materials like polyesters, nylons and acetal.

Sometimes it is obvious, sometimes it is impossible. It is hard to quantify and is often hard to keep consistent, thereby making it impossible to quantify.



Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[feaplastic]

Hello Patprimmer,

Thanks. I try to put the cad data or warpage result. But
Component is Automobile Front IP Panel (entire width of the car). It is totally visible in the car and our design is not totally different from existing designs.

I donot expect moldflow to predict exactly. But, how to interpret. When we see the plot with 0 to 24 mm, what do we interpret. In the plot, driver side is totally blue color (0 mm) and other side is 24 mm. Is it possible. That means IP is going down on one side. Is it mm or just relative units?

Or else, avoid doing moldflow warpage. just stop with flow analysis!!!!!

Thanks for ur opinion and help.

 

[elogesh]

Hi,

Instrument panel has many components.

Can you name the component (Center finish panel, defroster grille, Bezel, Register, speaker grill,etc) or else the rough size of the component?

24 mm is way off and I feel there is a miss in the analysis. Better to recheck the calculation.

Definitely we cann't expect 100% correlation between simulation and what is observed physically.

I am not sure whether PP can be used for the IP components.I was delaing with combination of PC an ABS.

We work closely with the supplier and had a quite reasonable success in recent times in intrepreting the results from moldflow towards reality. But needs to go a long way.

But definitely experts like patprimmer can give an insight about the warpage with his vast experience in plastics.

Regards,
Loganathan.E

 

[feaplastic]

Hello Loganathan,

Thanks. My component is top Instrument panel carrier which is one componenet for the entire width of the car. Later on, it is punched and all components which u mentioned above are assembled. Apart from top carrier, there are lower carrier, Air duct etc.,

You said you got a success (fairly) wtih moldflow. How do see that 24 as mm or some relative units.

It is prototype mold and we dont expect good parts. But how to analyse and understand. Hopefully, you could share ur exp in detail.

You are right. 24 mm is too high. We did not get 24 mm warpage. in serial tooling with sequential gate, moldflow says 6 mm warpage in Z direction.

By the way who is ur suppliers .(seems to be good supplier, you can share if it is not a problem for you). We look for new suppliers worldwide for Injection molding.

Hope other users also can share their experience.

 

[patprimmer]

I think 24mm warpage is quite possible in a GF PP moulding the size of a dashboard.

The variables that effect shrinkage are:-

Direction of flow.
Length of fibre relative to section thickness.
Flow path length.
Flow path over edges or obstructions that create turbulence.
Other non fibre fillers.
Section thickness.
Effective pack of the cavity.
Variations in surface temperature and heat sink capability of the mould.
Weld lines.
Mould coolant temperature.
Grade of base resin.



Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[feaplastic]

Thanks Patprimmer. Nice writeup abt warpage. Though, 24 mm is possible, in our prototype part both warpage pattern and the dimesnion (around 12 mm in different location) both do not correlate with Moldflow. Investigation is going on.

Still my question is unanswered regarding warpage plot interpretation frm Moldflow. Any help?

 

[mjh368]

have you posted on the moldflow.com forum