micro injection molding in Moldflow

[Anonymous]

Hello everyone,

we are trying to perform injection molding simulation of a part which is of the order of 1 mm.  the polymer is Ultem 1010.  In Moldlow's database, the quality indicators for ultem 1010 (for fill, pack and warp) are bronze. 

The warpage (seen during experiments) on the concerned surface of this part is around 1 um. Hence, i have some of questions:

1. can moldflow predict such small warpages?

2. As the quality indicators are bronze, for micro injection molding, do we need to go for material characterization?

3. what are the best practices for micro injection molding modeling?

Thanks,

Nikhil

[madhukeshwart]

1.simulating micro molding with Moldflow  will not be an issue.and can predict  warpage. Co-relating with actual is very difficult. as speed of fill, providing venting & measurement of warpage.

2. Best with gold quality for all the simulation.

3. Experienced person in micro-molding should comment on this & can give guideline

 Refer this link for guidelines & some points to note

Click this for study report

Similar question already came couple of times in forum

1. http://forums.autodesk.com/t5/moldflow-insight/moldflow-simulation-of-micromolding/m-p/2634336/highl...

2. http://forums.autodesk.com/t5/moldflow-insight/micro-injection/m-p/4805547/highlight/true#M3668

[bernor_mf]

Hi,

just wanted to add a link to a paper which has some insight to this as well:

http://www.academia.edu/20301273/Experimental_validation_of_micro_molding_simulations_using_differen...

Hope this helps.

Regards,

Berndt

[kristen.kilroy]

Hi @Anonymous, 

To add to the great references both @madhukeshwart and @bernor_mf provided, I've also listed the suggestions given through your support case below as a reference for others. 

1. Can moldflow predict such small warpages?
   • Yes (see below on best practices)
2. As the quality indicators are bronze, for micro injection molding, do we need to go for material characterization?
   • The quality indicators for materials are determined by a segment of criteria, shown in the attached screenshots. From looking at Ultem 1010's material data, the mechanical data for the material is being pulled from a similar generic material (since it is shown in red). Also, there is no measured shrinkage information listed. 
   • If you are looking for a good prediction for warpage, I would suggest it would be a good idea to get the material characterized, as using those values may introduce incorrect data, and at the small part level you are working with, it could be magnified.
   • If you do decide to get material characterized, you can reach out to our datafitting plastics lab for questions or quotes: datafittingmoldflow@autodesk.com.
   • In the inquiry, I would suggest mentioning that you will be using the material in a micro-molding setting, as well as 3D mesh. Micro-molding can experience very high shear rates. Normally the viscosity used in the Moldflow material data base cuts off below such shear rates. So any viscosity-shear rate-temperature data gained at high shear rates would be useful. The testing lab may be able to help measure these. 
3. What are the best practices for micro injection molding modeling?
   • A good correlation with real parts is possible when a finer 3D mesh is used. The number of layer through the thickness may need changed from the default to be sure no high-aspect ratios are caused by the finer mesh. 
   • Interia effects should also be are turned on (see: AMI Online Help: Simulate Inertia Effect).
   • As with any analysis, be sure mesh statistics are acceptable. 
   • Modeling feed and cool systems is also recommended to best simulate thermal influences both have on the material flow and warpage.

Cheers!