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Member
chooseanotherid
Posts: 4
Registered: ‎04-11-2014

what is pressure at V/P switchover

431 Views, 6 Replies
04-11-2014 03:48 AM

Hi guys,

 

I am a student who is studying with Mold flow 2010. During my using this software, I find difficult to distinguish between pressure at V/P switchover result and pressure result, can you help me?

 

Another problem is that in pressure at V/P switchover result, the composite did not fill completely all my object. Then what is problem and how to solve it. You can see the picture below to know more

 

Thanks!

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Distinguished Contributor
mayur_dhumal
Posts: 164
Registered: ‎05-05-2011

Re: what is pressure at V/P switchover

04-13-2014 09:26 PM in reply to: chooseanotherid
Hi,

V/P switchover is the transition from the filling stage to the packing stage during injection cycle.
Various switch-over methods can be used. For example, fill-to-pack switchover can be initiated when the injection time or pressure reaches a specified value, when a specified percentage of the volume is filled, or when other conditions are met.

In the image above you attached it shows the pressure at this transition. There is no problem with filling. For filling you need to see Fill Time plot result.

Please go through the Help to know more:
http://help.autodesk.com/view/MFIA/2014/ENU/?guid=GUID-21297F8A-3758-46F0-AD59-DF9407C6ABA0

Regards,
Mayur
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Member
chooseanotherid
Posts: 4
Registered: ‎04-11-2014

Re: what is pressure at V/P switchover

04-14-2014 01:52 AM in reply to: mayur_dhumal

Then it means that I can set the value of injection time or injection pressure to make the edge of 5 blades full of color? And can you explain clearly about this area? 

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Contributor
KaindlJ
Posts: 20
Registered: ‎01-03-2014

Re: what is pressure at V/P switchover

04-14-2014 04:41 AM in reply to: chooseanotherid

You do not want the part to be 100% filled at v/p switchover as it is bad for the molding machine and the quality of your finished product. The best analogy I can think of is driving a car to your house - Velocity control is like driving on a highway, full speed until you get to your house.  You then don't go 70 MPH into your garage and hope to stop before you hit the wall. Instead, you would slow down to maintain a speed that allows you to park accurately in the correct area, or use pressure control (or holding). Just like this analogy, it would be bad to bottom out the screw or suddenly jerk it to a stop from full velocity. This also maintains consistency for the packing of your part so certain ones aren't over packed while others are short shots based on lot-to-lot variations in materials.

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Member
chooseanotherid
Posts: 4
Registered: ‎04-11-2014

Re: what is pressure at V/P switchover

04-15-2014 01:33 AM in reply to: chooseanotherid

Nice comparison, KaindlJ

 

Can I understand that it is momentary status? Then why does moldflow announced that the pressure of these areas are 0 instead of not display pressure there?

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Contributor
KaindlJ
Posts: 20
Registered: ‎01-03-2014

Re: what is pressure at V/P switchover

04-15-2014 10:15 AM in reply to: chooseanotherid

Hi

 

I'm not sure what you're asking, according to your picture 4 of the fan blades have areas that are not filled, and the 0 areas are at the end of the flow front where you would expect them to be. That picture looks OK to me, except that the blade that is completely filled will be overpacked at the end of the pack + hold phase since it filled faster than the other 4. Ideally the flow front would reach the end of all 5 at the exact same time.

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Member
chooseanotherid
Posts: 4
Registered: ‎04-11-2014

Re: what is pressure at V/P switchover

04-16-2014 01:40 AM in reply to: chooseanotherid

Maybe I got it.

Thank all of you guy. Nice forum and Nice to see you 

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