Injection pressure

[AngelMelero5879]

How can I simulate a fill phase with a concrete injection pressure ?, p.e. I need to simulate a part fill phase using 120 bars, but the part not need that pressure, due to visual problems, the injection pressure in the real process is 120 bars, but in Moldflow the pressure is 70 bars, how can I do to use 120 bars instead 70 ?

[PaulGoldup3478]

Hi

Dont forget the Moldflow Software will not allow for any "pressure drop" through the nozzle on the injection unit, depending on the nozzle diameter this could range from 100-500bar specific pressure (10-50 bar). This could be a reason for the difference in pressure.

Speeding up the injection will increase the injection pressure but by 50bar??

Br

[raalteh]

Hi Angel,

I think specifying a pressure based injection profile is pretty unusual. You may want to check into this with the source. Is the 120 Bar the pressure at the end of the injection profile?

Regardless ... you can use a trick to pretty much reflect the 120 bar injection profile by:
1) Go to the 'process setting' > 'Advanced Options'. > hit the Edit button next tot the 'Injection Molding Machine' > Hydraulic unit. Specify a combination of maximum 'hydraulic pressure' and 'intensification ratio' that will produce a maximum injection pressure of 120 Bar. For the flow analysis, this will then limit the injection pressure that is available for the flow analysis.
2) Specify a VERY short injection time ... for instance 0.01 sec (but I don't know your product). The flow solver will try fill the part is that very short time, but hit the maximum injection pressure. After the max. injection pressure is hit, the solver will continue to fill the part with the maximum injection pressure (120 bar).

I hope this helps.

Hanno

[madhukeshwart]

Are you using "Dynamic Feed Control" for fill control


This feature uses pressure controllers at each gate in a mold, and Autodesk Moldflow Insight can simulate . Signals come from the pressure sensors of the hot runner system(s) to control multiple hot runner valve gates dynamically, in order to achieve a pre-determined pressure profile for each gate.

The general machine controller, or the central controller, is set to use a high (usually maximum) pressure, to ensure the flow-rate requirement for injecting the melt through the multiple valve gates controlled by the individual pressure controllers. There is no velocity/pressure switch-over, as there is no velocity control stage.

The application is typically used for multi-cavity and family molds, and for multi-gated large part injection moldings, in particular.

The current manufacturing set-up procedure is to use trial-and-error for an individual cavity to get a desired pressure profile as a "finger-print", and then apply it to individual valve gate controllers for the multi-cavity case. For a multi-gated large part, it is difficult to set up, which makes the software simulation very important beforehan