Hi,
For academic purposes, I am interested in comparing experimentally obtained shrinkage and warpage values with those obtained in Moldflow at various melt temperatures with the rest of the parameters kept constant.
For our experimentally obtained results, we use an injection molding machine with cooling channels that are not in use.
Our part is a simple dog bone shape. I am unsure how to replicate the situation where the cooling system is not used, since in real-life conditions, I would assume deflection due to differential cooling occurs.
By making the Warp analysis in Moldflow, the warpage increases with melt temperature due to no deflection due to differential cooling when I don't add the cooling channels. Thus I also assume the volumetric shrinkage would also vary with my real-life obtained data.
Thus, I am unsure how to replicate these real-life conditions since one of our purposes for using this tool in our course is to validate our analysis results with those experimentally obtained.
Thank you for the help!
Hi,
It is possible to run a cooling analysis without cooling circuits.
At least in Moldflow Insight.
If you are using Adviser, give it at try to run Cool if it passes without cooling circuits modeled.
I am not sure if works or not, and cannot test in Adviser myself right now.
Can a cooling analysis be completed without cooling lines in Moldflow?
Hope this helps.
Regards,
Berndt
Hi @bernor_mf ,
Yes, I am aware that I can run the analysis without the cooling lines. However, is it realistic to assume perfect cooling (isothermal) in a real-life scenario?
We will be comparing the volumetric shrinkage shown in both the moldflow analysis and the ones experimentally obtained from our injection machine (which doesn't use the cooling channels). I wonder if the volumetric shrinkage will vary by a considerable amount since I doubt there is perfect cooling in our real machine.
Thanks again for the help!
Best,
Paulina
Hi Paulina,
Generally, when you want to compare real setup the modeling should be as closed as possible.
I think you could simulate the real setup you have.
For common thermoplastic injection molding, the mold has the cooling circuits of course hence modelled in simulation.
If not having the cooling circuits, you could model that too.
From what I understand your mold has no cooling channels at all.
Now, if you use Fill+Pack, the surface temperature around cavity is the same, isothermal.
If you use Cool+Fill+Pack, the heat transfer from molten plastic to mold will be considered.
I did a simple test, and the isothermal temperature of 50C raised to 82C (average over cycle), with same cycle time.
This will have an effect, but it might be minor.
To learn what is needed I would try 3 scenarios in simulation:
Fill+Pack+Warp: isothermal cavity temperature
Cool+Fill+Pack+Warp : with cooling channels
Cool+Fill+Pack+Warp : without cooling channels
Using same process settings in filling and packing phase.
This to get an understanding of different scenarios, and their result.
Compare weight, volumetric shrinkage, warpage and so on.
Could then be use to decide how to model for real comparison.
Doing a comparison real mold and simulation could be quite extensive.
Attach a link. Is mainly for Moldflow Insight, but might be helpful for the understanding.
How to match simulation to reality with Moldflow Insight
Regards,
Berndt
What is the material? Cooling usually has a noticeable warpage effect on unfilled materials. With a filled material the fibers usually contribute more to warpage than the cooling. I am speaking very generally, but it may be something else to consider.
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