Sequential Injection

[Anonymous]

I've got a model with 2 hot gate. I've put a Valve Control on the second gate.
I would want to ask you two questions:

1 - The material starts from the first gate. When it arrives at the second gate this starts.
But when the second gate opens the first gate is closed. Why?
Is it possible the first gate is always open?

2 - Is it correct the first gate is closed during the packing phase? (you see image)

Thanks a lot

[madhukeshwart]

I think you have not created hot gate properties for both the gates .

If you provide hot gate properties for gate, it willl show when it opens and closes.

Now, since you have assigned hot gate properties for second gate(but number assigned in valve gate properties is 1 only)

Log file is showing when second gate opens and closes


Both should close after withdrawls of packing pressure.

If in doubt call back Edited by: madhukeshwart on Jan 16, 2010 1:07 PM

[Anonymous]

Hi madhukeshwart. Thanks for the answer.

The material part from the 1° gate.
When it arrives at the 2° gate the 1° is closed while the 2° opens (see image).

1-If instead I want the 1° gate is always open up to the end, as how do I do?

2-See the image attach, the 2° gate is closed later "Pressure released", is it correct?!?

thanks

Following the link for the image [http://img689.imageshack.us/img689/8059/log2p.jpg]

[madhukeshwart]

1. gate 1 should not have closed when gate 2 opens, chekc it gate one hot gate control settings.


2 . yes it is correct, when packing is released, it should close both gates. Gate 1 & Gate 2 should close at that time only.

but gate 1 is closing when gate 2 is opened & gate 2 is closed after withdrawl of packing


refer attached image ( set as it is in image for valve gate one ) & hope it will solve

With Regards
Madhukeshwar.T

[Anonymous]

Hi, I've followed your indications but it doesn't work.

I don't know the why.

[madhukeshwart]

Hi, screen out put shows gate1 is not closed in middle

and both the gates are closing after withdrwals of packing only

that's fine ... right ..

pressure graph shows sequential optin is working fine Edited by: madhukeshwart on Jan 18, 2010 8:25 PM

[Anonymous]

I have not understood two things.

1 - Because if I visualize the graph of the pressures for every gate it makes me see a line that goes down.

2 - In the pdf file, why the "flows rate, beams" results are red before and then blue?!? Should not be red both.
thanks

[madhukeshwart]

1. Pressure will go down after 2 nd gate opens as, pressure builtup in valve gate will realesse.

thats why pressure will come down at injection point , calmp tonnage requirement will come down , when you use valve gates.

2. even though flow rate beams seems to be blue ,they will not be zero but flow in that will be less , check with query results at node.


by screen output in pdf , it seems to be everything is fine , put query at local modlflow support team.

[Anonymous]

Thanks Madhukeshwart for your availability!!!

I have a last doubt on the position of the vave control and flow rate beams result.
You see the pdf file attached.

Thanks

[madhukeshwart]

Slide 1 is correct ,
slide 2 is correct,

In Slide 3rd,

At 1.95 s, when the gate 2 is open, the material volume in
gate 1 is 0.05 cm^3/s, It’s very strange.Why?

It will be slower, May be it is correct. , better creat feed system as in tool design.

Like single inlet to hot runner manifold, that will be divided in 2 hot drop.

Check the results.

[Anonymous]

OK, now It is clear!!!

Thanks for the time that you have lost 🙂

[teopado89]

Good morning, 

Can you tell me please benefits of a sequential gate during filling phase, and during packing phase?

thanks a lot!

[mayur_dhumal]

Hi,

When the flow is reached to Gate 2, it is opened.
at this point of time, gate 1 cann't push material, it is now used as for packing, because at this point material is getting froze very quickly. that's why flow rate is displaying 0.05 cm^3/s.

Regards,
Mayur

[madhukeshwart]

Benefits of sequential gates are many.

==========================================

1. It can be opened and closed at any point of filling phase and packing packing phase.

2. It can be used to control pressure

3. It can be used to control tonnage.

4. It can be used to avoid or minimise or relocate weld lines.

5. It can be used to improve filling and packing phase.

6. It can be used to less gate vestige purpose only.

7. It can be used to fine tune warpage.

8. It can be used for family mold flow balancing.

You need to understand and select as you wish to use.

[teopado89]

Thanks madhukeshwart for the answer.
Excuse me if i abuse of your patience, but can you tell me (or tell me where to find this answer) what to do to obtain benefits you are saying?
I mean for example if the benefit would be "controll weld line position" i could say a possible way is to reduce thickness were i want to slow down the flux.
So connected to your list, for example what have i to do to improve filling and packing?
I'm asking because my client has spcifically requested a sequential gate to improve packing, but i don't know how a sequential gate can improve it.

Another thing please:

my study is composed by 3 shots, of the same material (different colours).

Obviously i'll start with the analysis of the 3 parts individually, but then what do you suggest?

1 overmolding with first and second part?

1 more overmolding with second and third part?

or one analysis with first and second parts analized like inserts in the third part?

Could it be a smart solution to use an overmolding analysis, with first shot made by first part and the second part with a sequential gate which will open after the whole cycle time of the first part, and then the third part as a second shot? But i don't know how to set packing pressure profile in this case...

Thanks Thanks Thanks Thanks Thanks Thanks 

[teopado89]

Please does anyone who know the aswer may help? Thanks

[madhukeshwart]

can you tell me (or tell me where to find this answer) what to do to obtain benefits you are saying?

I mean for example if the benefit would be "controll weld line position" i could say a possible way is to reduce thickness were i want to slow down the flux.

Difficult to get examples as mostly NDA will stop everyone to share case studies. You  learn how to use and sequential gates.

 Try to controlling the valve gate timing to get a weld line positions, with multiple gating option.

For example: 1. if we open two gate at a time, what happens. Where welding will come ?

                          2. If we open one drop early and other late by 0.2 sec for example. Vice versa

                          3. If we open one drop early and other late by 0.4 sec for example. Vice versa etc …try with different combination of valve gate opening timings.

So connected to your list, for example what have i to do to improve filling and packing?
I'm asking because my client has specifically requested a sequential gate to improve packing, but i don't know how a sequential gate can improve it.

I assume, you know, how gate location, packing pressure and time of packing effects on volumetric shrinkage , which itself enough.

Try different combination sequential gate opening and close. Try to achieve uniform volumetric shrinkage across the part. You itself can have your own example,

Another thing please:

my study is composed by 3 shots, of the same material (different colours).

Obviously i'll start with the analysis of the 3 parts individually, but then what do you suggest?

1 overmolding with first and second part?

1 more overmolding with second and third part?

or one analysis with first and second parts analized like inserts in the third part?

Could it be a smart solution to use an overmolding analysis, with first shot made by first part and the second part with a sequential gate which will open after the whole cycle time of the first part, and then the third part as a second shot? But i don't know how to set packing pressure profile in this case...

‘Over molding simulation of 3 shot tool’ is not possible right now. Ignore any one or try with 3 combination.

1.      1+2 shot as two shot mold and 3rd shot as insert
2.      1+3 shot as two shot mold and 2nd shot as insert
3.      2+3 shot as two shot mold and 1st shot as insert
4.      1+2 in one shot & 3rd part in 2nd shot …..etc. …………………… Results will help you to take decision

[teopado89]

Ok thanks for the answer.

I'll try these days!