Anisotropic Viscosity Modeling for Injection Molding Ear Flow

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Solution Overview

Problem

Current predictive engineering tools provide unsatisfactory simulations of 'ear flow' in injection-molded plastic articles, particularly for neat polymers, as they fail to accurately model the anisotropic viscosity distribution and its impact on flow behavior within mold cavities.

Innovation Solution

A molding system that generates an anisotropic viscosity distribution in the mold cavity based on the volume fraction and aspect ratio of fibers, using a processing module to control the molding machine and simulate mixed shear and extension viscosities, thereby improving the simulation of ear flow and other complex flow phenomena.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional predictive engineering tools are used to simulate injection molding, then the simulation process is simple and fast, but the accuracy of ear flow simulation is unsatisfactory

Engineering Contradiction:
Improveear flow simulation accuracyVSAvoidmolding system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by introducing anisotropic viscosity as a key parameter to replace conventional isotropic viscosity models. The anisotropic viscosity is calculated based on fiber orientation tensors and incorporates fiber volume fraction and aspect ratio, allowing the simulation to accurately capture the directional dependence of viscosity that causes ear flow. This parameter change enables conventional simulation tools to achieve high accuracy without requiring complete system redesign.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials approach by combining multiple factors (fiber orientation, volume fraction, aspect ratio, shear rate, extension rate) into a comprehensive anisotropic viscosity model. This composite model integrates the effects of different physical parameters to create a unified viscosity representation that accurately predicts ear flow behavior in fiber-reinforced thermoplastic composites during injection molding.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If anisotropic viscosity distribution is calculated considering fiber orientation and flow conditions, then ear flow simulation accuracy is improved, but computational time and processing complexity increase

Engineering Contradiction:
Improveflow phenomenon simulation accuracyVSAvoidsimulation time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing fiber orientation tensors and anisotropic viscosity values during the simulation process. The anisotropic viscosity is computed based on fiber orientation distributions and flow conditions at each step, allowing the simulation to efficiently predict ear flow without requiring time-consuming iterative calculations during the actual molding process simulation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the viscosity parameter from isotropic to anisotropic form, which allows the simulation to capture directional flow effects more accurately. The anisotropic viscosity model incorporates fiber orientation tensors and flow invariants, enabling the system to compute viscosity at different locations and times efficiently while maintaining high accuracy in predicting ear flow and other complex flow phenomena.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If conventional isotropic viscosity models are used, then the simulation model is simple and easy to implement, but it cannot accurately simulate ear flow in neat polymers

Engineering Contradiction:
Improveear flow simulation accuracyVSAvoidviscosity model complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent fundamentally changes the viscosity parameter from isotropic to anisotropic form. The anisotropic viscosity model incorporates fiber orientation tensors, volume fraction, and aspect ratio to capture the directional dependence of viscosity. This parameter change enables the simulation to accurately predict ear flow in neat polymers by accounting for molecular orientation effects that conventional isotropic models cannot capture.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies composite materials approach by integrating multiple factors (fiber orientation, volume fraction, aspect ratio, shear rate, extension rate) into a comprehensive anisotropic viscosity model. This composite model combines the effects of different physical parameters to create a unified viscosity representation that accurately predicts ear flow behavior, extending the successful fiber-reinforced composite viscosity models to neat polymers.

Inventive Principle:
Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system enhances the accuracy of injection-molded plastic article simulations by considering the integral effect of fiber volume fraction and aspect ratio, leading to improved flow rate and simulation of significant flow phenomena like ear flow and jetting flow.

Implementation Method 1

generate an anisotropic viscosity distribution of the molding resin in the mold cavity based on a molding condition for the molding machine; wherein the anisotropic viscosity distribution of the molding resin is generated based in part on consideration of an integral effect of a volume fraction and an aspect ratio of the plurality of fibers

Methodology Applied
Scientific EffectAnisotropic viscosity: Anisotropy

Implementation Method 2

the mixed anisotropic viscosity distribution of the molding resin is generated by taking into consideration an extension rate distribution and a shear rate distribution of the molding resin

Methodology Applied
Scientific EffectShear thinning: Shear Thinning

Implementation Method 3

the mixed anisotropic viscosity distribution of the molding resin is generated by taking into consideration an extension rate distribution and a shear rate distribution of the molding resin

Methodology Applied
Scientific EffectExtensional viscosity:

Data Source

PatentUS11065795B1Molding system for preparing thermoplastic composite article
Publication Date: 2021.07.20 CORETECH SYST CO LTD
  • US11065795B1 patent drawing
  • US11065795B1 patent drawing
  • US11065795B1 patent drawing

AI summary

The present disclosure provides a molding system for preparing an injection-molded plastic article. The molding system includes a molding machine; a mold disposed on the molding machine and having a mold cavity for being filled with a molding resin including a plurality of polymer chains; a processing module configured to generate an anisotropic viscosity distribution of the molding resin in the mold cavity based on a molding condition for the molding machine; wherein the anisotropic viscosity distribution of the molding resin is generated based in part on consideration of an integral effect of a volume fraction and an aspect ratio of the plurality of fibers; and a controller coupled to the processing module and configured to control the molding machine with the molding condition using the generated anisotropic viscosity distribution of the molding resin to perform an actual molding process for preparing the injection-molded plastic article.