Machine injection time

[alberto.capra]

Hi!

I'm Alberto, a student of mechanical engineering from the University of Parma.

I'm doing an analysis with this software and I have a problem with the "machine injection time" (in the process settings wizard).

I don't use the default values of the injection time because I want to specify mine. I set 0,95s and after the analysis, in the Summary sheet named "Fill" I see that the fill time (until switch-over) has a different value (0,73s).

What's wrong? Did I not understand the difference between the two? Are thesetwo different injection time?

Thank you

Alberto

[nordhb]

Hi,

the injection time set, calculates a flow rate depending on volume to fill.

Fill Time is the result, when cavity is filled to 100%.

The fill time set and actual Fill Time differs due to melt compression, when switch over from velocity to pressure phase happens.

The last volume to fill by pressure normally reduces flow rate.
This depends on packing pressure, but as default packing pressure is 80% of injection pressure, the packing pressure to fill normally reduces flow rate.

So what you see is right - swich over from velocity to pressure phase happens earlier in the filling phase, around 95-99% filled cavity.

At 0.73s, then the filling by pressure takes a bit longer as lower flow rate, and you end up with a fill time around 0.9-1s or so.

Hope this clarifies.

Regards,

Berndt

[alberto.capra]

Thank you nordhb, now I understand the difference!

Regards,

Alberto