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Active Member
inbasudhahar
Posts: 8
Registered: ‎07-14-2010

Fill control: Absolute ram profile

871 Views, 4 Replies
02-02-2011 08:06 PM

Hello,

 

 please explain about absolute ram profile. how can i create this profile for new component development. suppose i have this profile from customer, based on this ram profile how can i select a injection machine.

 

Regards,

 

Inba sudhahar

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Product Support
nordhb
Posts: 455
Registered: ‎03-23-2009

Re: Fill control: Absolute ram profile

02-02-2011 11:37 PM in reply to: inbasudhahar

Hi,

Absolute profiles are used when key machine parameters are known, such as screw diameter and maximum injection rate. Screw diameter needed to get flow rate right.
So using absolute profiles you need data of injection molding machine.

 

Settings in the injection molding machine properties.
You can get to this dialog by selecting Analysis > Process Settings Wizard,
select Advanced options, edit the Injection Molding Machine,
select the Injection Unit tab, then enter the Screw diameter.

 

When using absolute ram profile, one also have to choose how this profile is set, meaning
specify the two variables by which the ram speed profile is controlled such as:
- Ram speed vs Ram position
- Flow rate vs Ram position
- and more...

 

Regards,
Berndt



Berndt Nordh
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Member
flowvee
Posts: 4
Registered: ‎11-27-2009

Re: Fill control: Absolute ram profile

02-10-2011 03:04 AM in reply to: inbasudhahar

Hi ,

To reach to a reasonable profile, I would prefer to start as per below for "Ram Speed vs Ram position"

- First calculate the shot weight

- based on the known density of the polymer, you will reach to volume required in the barrel

- Once you have the data of the molding machine, that is screw dia, so you have the area

- Now, volume = area x distance(length), so, volume / area = distance, meaning you have the screw position. Take this as a starting ram position + cushion

 

Regarding the speed, one should decide the speed such that the viscosity of the molten polymer should be uniform for the better filling of the cavity.

To arrive to the uniform viscosity, one can run the different iteration and calculate the viscosity = peak pressure x fill time for different iterations, than plot the graph of viscosity as function of speed. look for the speed which can have uniform viscosity. Based on the speed arrived run the analysis with "Ram speed vs ram position"

 

Best Regards

 

Veeshal S.

 

  

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Active Member
FK1985
Posts: 9
Registered: ‎06-01-2011

Re: Fill control: Absolute ram profile

10-14-2011 10:57 PM in reply to: flowvee
how is it calculate starting ram position for 3D moldflow Regards Sandokan
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Active Member
M.Nasir
Posts: 6
Registered: ‎05-28-2013

Re: Fill control: Absolute ram profile

11-14-2013 02:13 AM in reply to: flowvee

Hi..

 

I am interest with your answer in order to find the ram speed. Did you refer any journals or books for your justification on that particular solution?Because I need the references on that.

 

Thank you

 

Regards

 

Nasir

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