Cycle Time

[JoãoEsteves6798]

Hello,

One of the problems i have in Moldflow, is how to calculate the correct cycle time of a part.
Sometimes my colleagues ask me to calculate cycle time only to compare with the value of the injection machine (reality).
Other times i have to give them the cycle time for a quotation of a part, and this is real important.

I usullay use the values of : FILL TIME + TIME TO REACH INJECTION TEMPERATURE = cycle time
(ex: fill- 1s / time to reach injection temperature- 12s -> 1+12=13s

I run only FILL+PACK+WARP analysis, and i know (fill+pack) values.
But what is the cool value??

How can i calculate Cycle Time correctly?

thanks,
João Esteves

[Jay.Shoemaker]

Good Day,

The way you defined cycle time is reasonable, Injection time + Time to reach ejection temperature. The main issue is definitions. Time to reach ejection temperature from a Fill + Pack analysis starts at the end of fill and is ends when 100% of the cross section reaches the ejection temperature. If the packing analysis is run, you can set the cooling time calculation to automatic. A packing analysis always includes the "cooling phase" so you don't need to add a cooling time in. When this is done, you can adjust your ejection criteria by changing the reference temperature (ejection temperature) or the percent frozen. When comparing to reality, you have to keep in mind a couple things. One parts can be ejected before the cross section is completely frozen. This is particularly true when you have localized thick regions of the part. You can't simulate how frozen a part must be to eject. All you can do is have some sort of benchmark and compare differenent analyses to this benchmark. Also when comparing to reality, what is the mold temperature used in the simulation to the actual mold temperature (plastic/metal interface) used on the production floor. Chances are they are not the same. With the Fill + Pack analysis you are assuming a constant mold temperature and the production mold will not have a constant temperature. Even if you look at the average actual mold temperature how close is that to the simulation, chances are it will be different. A molding window analysis will give you a good idea of the sensitivity of mold temperature on cooling time. This will help you figure out how critical the mold temperature will be.


The biggest issue is how frozen the part will need to be to be ejectable.

Regards,
Jay

[kameshwarang]

hi all,
using moldflow you can predict only the IPC time( injection, packing and cooling).whereas a real time cycle time involves other time like moldopening, ejection, degasing, and various others.For the IPC time, it would be available in the log of the analysis.

[Gunakar]

What wonders me is that there is no one solid way to predict the cycle time in spite of Moldflow. I would ideally have material info, 3d model, and machine info. It would be nice if Moldflow could give 3 versions of cycle time based on low cooling, medium cooling and high cooling as ideally during the time of Project Quoting one would not spend time in designing a cooling circuit. Please educate me if I missed any critical info.

Thanks~GK

[praphotSYZN3]

Sorry I  don't know where is log file. Guide me  the location of log file please.

[bernor_mf]

@praphotSYZN3
Hi,
the log file is available with open study and "Logs", just above Results symbol.

But you do not need to open study. Hover over study name, right-click and in bottom of context menu you have "View Logs".

Also, have a look at this:
Study log
Access the Study Log
Saving the Analysis Log to a text file

Hope this helps.

Regards,

Berndt

[praphotSYZN3]

Dear Mr. Bernor

I follow your recommended but not find total cycle time ,please guide me again about how to find total cycle time of molding process (Fill+Pack+Cool+Mold open)

[bernor_mf]

@praphotSYZN3 

Hello,

well, in process settings for Cool analysis you have:
Mold open time
and
Injection + packing + cooling time (IPC)
The total sum Mold open time + IPC gives cycle time.

In Analysis Log, you need to scroll through and look for it.
For a Cool analysis, you find "Cycle Time" below
"Summary of Cavity Temperature Results"

For Cool(FEM) type, "Cycle Time" text is not there. Use:
Injection + Packing + Cooling Time
and
Mold open time
And sum up.

You could right-click in Analysis Log window, when opened below graphics display, and do Save As...
Then open file in text editor and you could search for words.

Hope this helps.
Regards,
Berndt

[praphotSYZN3]

Dear Mr. Bernor

Thank you for recommended ,I follow your guide and it is success.

As below picture  use process F+P+W analysis. I have some questions.

1. This is 28.89s ,is it real finish time in analysis process (F+P) yes or no and then should I look where finish time?

2. Time control (fill) , should I integrate it to finish time total (F+P)? or or it is integrated already.

[bernor_mf]

Hi @praphotSYZN3 

well, yes a finish time if last time step.

When running FPW (Fill+Pack+Warp), and you find the relevant process settings, you need
to add time for open/close mold. This means open mold, eject, pick by robot, etc, close mold.

Default Mold-open time is 5s, but it is set in Process Settings when running CFPW (Cool+Fill+Pack+Warp).
When not running Cool, the mold temperature will be as set in Process Settings, Mold surface temperature,
and the same temperature all around cavity.

1) Yes, a finish time if last time step result is shown.
Confirm by review your Analysis Log information.

2) No.
You need to add time for open/close mold for FP (Fill+Pack) analysis.

This means time to open mold, eject, pick by robot, etc, close mold.
5s might be too short. Depends on size of mold, injection molding machine and adjacent equipment.

It is important part reaches a temperature where it can be ejected without being damaged.
Cold runners does not necessarily need to be fully frozen to be ejected. If not too soft,
they could be ejected when not fully frozen maybe down to 50%, but could vary too, of course.

On-line help on: Cycle time

I still think you should review Analysis Log for details.

Hope this helps.

Regards,

Berndt

[praphotSYZN3]

Dear Mr. Bernor 

Thank you for your suggest.