The problem about plastic parts (sink mark)

[Sandokan_85]

Hi Dear,

I would get technical support about Moldflow.We produce a part with two different material as ABS and ASA.You can find the basic dimensions of part which I mentioned on the attach.

When I make sink mark analysis on moldflow, I can see sink marks about 0.0090mm-0.0195mm on analysis.

According to my experiance; İf we see this values on moldflow,normally we can't notice the sink marks on real part.But we see sink marks.

Is there any special values for ABS and ASA material for non noticeability on real parts?

What do you think about our values(0.0090mm-0.0195mm)which we see on sink mark analysis?

[HugoHerrera7042]

Hi Sandokan,

there is not really a way to tell wether the sink mark estimate output will be noticeable or not...

i personally like better the volumetric shrinkage result (3d), since i can always cut sections and view through the thickness how much it is shrinking (to address sinks, voids)...for this result, anything above ~6-7% is most likely a visible sink.

one thing to consider is to make sure you are matching exactly the process conditions from the machine for both materials. just FYI, a lot of times packing profiles are not the same and this gives false numbers to compare...

from the design standpoint i see you are dealing with a 50% rib-to-nominal-wall ratio, which should not be an issue...

is this a 3d mesh approach? fine mesh quality at this area is also an important thing to consider.

good luck!

Hugo Herrera

Visteon

Mty, Mexico