Multiphase, Dual Polymer Injection Molding & Cooling of Open … · 2009. 12. 1. · Research &...

Research & Development, FEA, CFD, Material Selection, Testing & Assessment

Multiphase, Dual Polymer Injection Molding & Cooling of

to form both distinct & graduated material Open Cavity

properties within a complex body

Presenter: Mark Yeoman

Date: 16 October 2009

© Continuum Blue Ltd.

Date: 16 October 2009

Presented at the COMSOL Conference 2009 Boston and Milan

Implant DesignGeneral Soft Tissue Mechanics

• Nonlinear, Hyper-elasticNonlinear, Hyper elastic

• Anisotropic/Orthotropic

• ViscoelasticViscoelastic

Ideal Implant Mechanicsdea p a t ec a cs

• Duplicate or augment the natural response of body

Ligament Replacement & Augmentation System (LARS), used for massive

tissue/ physiological function

R&D, FEA, CFD, Material Selection, Testing & Assessment © Continuum Blue Ltd

( ),rotator cuff repair

Novel LARS Implant

Novel elastomeric, rotator cuff LARS


P l 1

Material Regions

Graduated Region

Polymer 1

Generalized Force Displacement Material

Region Curves

AA

Polymer 2

Region Curves

Forc

e

BB

S ti A ASection A-A

Section B-BDisplacement


Manufacture ProcessAim is to find the production & process parametersrequired to produce the elastomeric implant, using a

• Reduce production costs

single injection mold process.

educe p oduct o costs– Single process

– Reduce physical handingReduce physical handing

– Increased production yields

– Reduce QC stepsQ p

• Increase integrity & homogeneity of implant– Reduces the delaminating & bonding issues


Reduces the delaminating & bonding issuesfound in layered production process

Model GeometryModel Geometry, Domains & Boundary Conditions

Gas (Atmosphere)

Initial Subdomain Phases

Solid (Mold)

Fluid (Polymer Solution)


COMSOL Model Overview

• 3 Transient Modules utilized:• Two-Phase Flow Laminar Phase Field (chns)Two Phase Flow Laminar Phase Field (chns)

• Phase Field (mmpf)

• Convection & Conduction (cc)

• Two-Phase Flow Laminar Phase Field• Models Fluid-Air Boundary Flow

• Phase Field• Models 2 dual injected polymer solutions

• Convection & Conduction


• Models thermal changes (Solid, Fluid & Gas)

Density & Viscosity FunctionsCh i d i i it & d it t t f thChange in dynamic viscosity & density vs. temperature for the two polymer solutions used in the injection mold process


Inlet Injection ProcessMold machine polymer 1 & polymer 2 injection flow profiles vs. time.


Simplified Inlet ConditionSi lifi d i l t diti t i l t ditiSimplified inlet condition to equivalent condition:

• Smooth inlet flow function implemented• Combined flow rate & volume fraction


Equations & Boundary Conditions

}]×Vf)(T-)(T+{[)(T=)(T poly mmpf

poly cc

poly cc

poly cc

fluidchnscc

2121

}]×Vf)(T)(T+{[)(T)(T poly poly poly poly fluid 2121

chnscc=

}]×Vf)(T-)(T+{[)(T=)(T p ymmpf

p ycc

p ycc

p ycc

fchnscc

+B=A×phik chnscc chnscc

+E=D×phiC chnspcc

Subscripts

Superscripts

Poly 1

COMSOL Multiphysics module

Material phase or state: solid, gas, fluid

1st Polymer material/solution

=

=

=

chnsmmpfcc =u= uuPoly 1

Poly 2

A, B, D & E

k

1st Polymer material/solution

2nd Polymer material/solution

Various material dependent constants

Thermal Conductivity

=

=

=


Cp

u

y

Heat Capacity

Velocity Field

=

=

Validation (Thermal Data)d d h l f l d d lTime dependent thermal response curves of validation model

vs. physical data at three different & distinct locations

R&D, FEA, CFD, Material Selection, Testing & Assessment © Continuum Blue LtdNB: Validation data done on a different 3D Body

Validation (Cured Sections Data)Partial view of a cured section of a molded device, illustrating the distinct cured polymericregions (1 & 2) and comparison to the equivalent COMSOL model.

R&D, FEA, CFD, Material Selection, Testing & Assessment © Continuum Blue LtdNB: Validation data done on a different 3D Body

Fluid Fill & Polymer Regions


Thermal Effects During Filling


Continued Flow After Injection


Conclusions

• COMSOL Model successfully modeled the filling & curing of

an open cavity mold with a combined polymer solution atan open cavity mold with a combined polymer solution at

an elevated temperature through a single port to produce

vary graduated and distinct materials regionsvary graduated and distinct materials regions

• The COMSOL Model developed was validated against:

• Quantitative thermal data

• Quantitative cured sections

• Qualitatively against captured video footage of filling process


Qualitatively against captured video footage of filling process

NB: Validation data done on a different 3D Body

Future Developments

• Additional polymer solution (3rd polymer)

• Multiple inlet & outlet locations across the mold

cavityy

• Time dependent curing function (specifically

required for 3rd polymer)

• Multi-parameter optimization of the injection flowMulti parameter optimization of the injection flow

inlet profiles, mold temperature & polymer inlet

temperatures


temperatures

Research & Development, FEA, CFD, Material Selection, Testing & Assessment

Contact Details

Dr Mark YeomanE: [email protected]

M: +44 (0) 7916 283 970

T: +44 (0) 1342 824 921

W: www.continuum-blue.com

© Continuum Blue Ltd.

Multiphase, Dual Polymer Injection Molding & Cooling of Open … · 2009. 12. 1. · Research &...

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