Flow Function Overview

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Flow Function Overview

Fill percentage to stop calculation means the percentage where a filling analysis stops. The default value of Fill percentage to stop calculation is 99.95%, which is different from the default value of Packing Switch in Moldex3D Process Wizard. In order to prevent the pressure peak above the packing pressure, filling behavior is switched to pressure controlled phase at switchover point when 98% of cavity volume is filled as shown. However, the setting of Fill percentage to stop calculation is flexible for users to stop the filling analysis at any filling percentage. For example, if Fill percentage to stop calculation is set as 30%, the filling analysis will stop after 30% of cavity volume is filled as shown. This function is useful for users to preview the filling behavior at any filling percentage.

 

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The figure shows Sprue pressure versus time during filling analysis

 

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If fill percentage to stop calculation is set as 30%, the filling analysis will stop after 30% of cavity volume is filled

 

Advanced Fiber Orientation setting

In Computation Parameter column, users can find fiber parameter under the Advanced Options for Filling/Packing Solver option. In fiber parameter option, there are three new approaches to improve the fiber orientation accuracy for short or long fiber-filled composites.

 

The first approach is the 4th orientation tensor closure. It includes three methods: Hybrid (Original Moldex3D fiber orientation calculation solver model), ORE (Orthotropic closure approximation model), and IBOF (Modified orthotropic closure approximation model). The properties of the three models are listed below.

 

Hybrid

Short computation time

Fiber orientation tensor over-estimates at skin

Moderate fiber orientation prediction accuracy

ORE

Improvement of fiber orientation tensor over-estimating problem

High fiber orientation prediction accuracy

Long computation time

IBOF

Improvement of fiber orientation tensor over-estimating problem

High fiber orientation prediction accuracy

Short computation time

 

The second approach is the Rotary Diffusion, which is to describe the fiber-fiber interaction. It includes three methods: Folgar-Tucker (Original Moldex3D fiber orientation calculation solver model), ARD (Anisotropic Rotary Diffusion Model) and iARD (Improved Anisotropic Rotary Diffusion Model). The properties of these models are listed below.

 

Folgar-Tucker

Account for the fiber-fiber interactions with isotropic rotary diffusion which can help users to capture the short-fiber orientation distribution profile.

ARD

Account for the fiber-fiber interactions with anisotropic rotary diffusion which can help users to better capture the long-fiber orientation distribution profile.  The drawback is there are five parameters to set.

iARD

Account for the fiber-fiber interactions with anisotropic rotary diffusion which can help users to better capture the long-fiber orientation distribution profile. Only two parameters are needed.

 

The third approach uses the Retard Principal Rate (RPR) to consider the Fiber-Matrix interation, and hence improve the original Folgar-Tucker model’s approach, which over-estimates the changing rate of the orientation tensor in concentrated suspensions. The RPR model alpha factor is suggested to be from 0 to 1 (the larger factor value is, the more obvious RPR effect is).                            

 

 

Basic Functions of Flow Analysis for Solid Model

For flow analysis of Solid/eDesign model, the basic functions are as follows.

Capability: solving the filling-related problems, such as:

short-shot (incomplete filling),

weld line, air-trap,

flow problems,

burning surface defects,

runner/flow balance, and

gate design problems.

Result analysis: the analysis results can be viewed through the demonstration of field plot on Display Windows controlled by Project Workspace, Display Toolbar, and Animation Toolbar, or it can be shown by XY Curve.