topic Re: Clamp force: XY Plot in Moldflow Insight Forum

Clamp force: XY Plot

praphotSYZN3 — Thu, 30 Mar 2023 07:02:54 GMT

Why clamp force: XY Plot less than the Pressure at injection location: XY Plot.?

Please, suggestion to me about how to be fixed.

Question from me.

1. Am I setting it right?

2. How should I fix it? if not correct.

See my process setting see at below.

1.Packing pressure setting

2.Injection Molding Machine (Max=160)

3.Results (Injection pressure v Clamp force)

Re: Clamp force: XY Plot

h-fujitaDXJU5 — Thu, 30 Mar 2023 08:19:19 GMT

Clamping force is not pressure(Pa). 1 ton is 1000 kilogram. (Average)pressure times area is force.

Pressure at injection point is highest pressure of the mold.

In holding(packing) phase, all area's pressure are same, if no flow and no compression behavior of material.

Sprue, runner and gate "eat" the injection pressure before pressure is arriving molding part.

So any portion of the molding part's pressure is lower than injection point.

And some frozen area can't transfer pressure anymore. Also frozen area have been holding packing pressure after injection(packing) pressure reach zero MPa.

I think two causes are affected to tonnage (1)compressibility of molten polymer, (2)frozen area cannot transfer injection pressure to far portion of the molding part.

Regards

Re: Clamp force: XY Plot

praphotSYZN3 — Thu, 30 Mar 2023 08:50:40 GMT

Thank you for suggestions to me.

Re: Clamp force: XY Plot

PascalGosset — Mon, 03 Apr 2023 13:02:57 GMT

Hi simulators,

I made a little sample to show you the difference between the pressure and the clamp force.

Please, see my picture below.

It's a plate 25 cm x 6 cm (projeted area: 150 cm²).

At switchover, the pressure in the sprue reaches 116 MPa (i.e. 1160 bars).

Then, I applied 2 packing steps: 80% of the switchover during 2 s + 50% / 3 s.

(Your setting of the packing is very high. The Moldflow default is better: 80% / 10 s).

The clamp force plot shows the maximum value occurs after the switchover.

Generally its during the 1st packing step, when the pressure in the cavity is maximum.

Here: 139 T = 928 bars x 150 cm²

I see you modeled 16 cavities.

You could save calculation time with the "occurrence" attribute.

The results will be the same.

Look here: Moldflow Insight Help | Occurrence numbers | Autodesk

Good luck.

Re: Clamp force: XY Plot

praphotSYZN3 — Wed, 05 Apr 2023 03:02:55 GMT

Dear Mr.PascalGosset

I have a question about my injection condition below. Did I enter the values in the process settings below correctly? and if not correct I should solve this problem.

Re: Clamp force: XY Plot

PascalGosset — Wed, 12 Apr 2023 09:56:21 GMT

Hi all,

Sorry, I only just saw your question.

Yes, your settings are correct.

In order for Moldflow to follow your pressure profile exactly, the number of intermediate results must be increased.

By default, there are 20 while the filling and 20 while the packing.

In the example below, we see that the end of the first packing step has been shortened.

With 40 intermediate results, the problem is solved.

This calculation option can be found in:

Process settings / Advanced options / Solver parameters / Intermediate Output / Number of regular results