clarification on best gate location

[ramabalaji]

Dear sir,

we usually carry out gating suitability analysis to reduce iteration, since best gating suitability will be ideal,

but for the attached part i have got drastic drop at pressure at injection location,

Pl refer the attached image for your referene, do get you views in this regard,

My observation is that, since there flow length has got reduced there is drop in the injection pressure,

thanks, Ramabalaji.K

[PascalGosset]

I do not use this kind of analysis because I think it only takes into account the flow lengths.

But your trouble does not come from the flow resistance in the part.

The increasing of pressure comes from the cold runner much longer in the case 2.

[nishit78]

While the moldflow help says that the gate location analysis uses more than just the flow lengths to recommend a gate location i have never had much success with the outcome of the gate location analysis.

Somehow it has always picked the approximate center of the part, and in my opinion, totally ignoring the thickness differentials that create pressure variations and require different gate locations than just geometric/visual balanced flow paths.

I agree with Pascal, i dont spend any time running a gate location analysis unless it is a true dual domain meshable model.

[raalteh]

Two comments:

1) I agree with the two previous responders that the is very likely a big influence from the runner system you built.

2) The gate location solver(s) actually do account for thickness variations and are not 'picking' the geometric center of the part. The geometric center of the part may actually be the place where injection molding process experiences the least amount of pressure drop (which is the main optimization objective).

Not everybody should fully rely on the gate locator; often times, a human knows more about the context of the mold, and automatically eliminates a few scenarios. However particularly when multiple gates are needed, the gate locator can help suggest some valid scenarios you would not have thought of, or at least point in the right direction.

I hope this helps

[Anonymous]

It is not very useful to use this best location analysis

1) If you discuss the part design with designer he and the customer can tell you the optical requriments of the part you can select the area where you dont want the gate location and run the best gate location analysis

2) If you ask a moldmaker he will for sure use his experience for this and not Best gate location analysis.

3) looking at you are injection location in first case if you are forcing the polymer melt perpendicular to the rips for sure you need more pressure and if you go parallel you will need less preesure

4) And please dont take 100 % assurance that the pressure drop will be the same on IMM

All the best

Sadashiv

[rajeshkumarpv]

Hi,

Please ceck the pressure drop across the feed system this should give you an idea. The Pressure required for the part should be almost close.

Regards,

Rajesh PV

[Anonymous]

Please do check the Pressure drop because i think the flow in the same direction with ribs will give less pressure

thanks for ur reply