Max Shear rate and shear stress

[GilPolymers]

Hi all,

I'm looking for literature that could help me to define limits on the shear that you can apply to a certain polymer family.

In the books that I have (for example: Runner and Gating Design Handbook: Tools for Successful Injection Molding and Mold Engineering) I have a table and some charts which for me are not good because are not related with the time that you apply the shear.

I mean, If you apply a shear of 40000 1/s in a gate w/ 0.5mm land is not the same as if you apply the same shear rate in a shell part w/ 50mm length.

I was wondering you people know where I can get a kind of chart relating max. shear w/ time that the shear is applied.

I know that even for the same materials the use of for example a flame retardant is limiting the shear, or the use of some fillers. I also know that most of the people gets this knowledge by experience. I studied 5 years polymer engineering (lots of theory) and I'm working since 1 year in the mold industry but not really dedicated to applications, so I didn't have the time or change to improve that "feeling". Would be good if some science could help

Thank you a lot, any answer will be helpfull.

Gil

 

[patprimmer]

I have never seen such data as such, but some manufacturers publish data on flow length to thickness ratio combined with some moulding conditions. This may help you understand or define some limitations.

Regards
Pat
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