Numerical modelling of complex parison and sheet formation in blow molding processes using BlowView Software

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Numerical modelling of complex parison and sheet formation in blow

molding processes using BlowView Software

(2)

Numerical Modelling of

Complex Parison and Sheet

Formation in Blow Molding

Processes using BlowView

Software

Zohir Benrabah & Anna Bardetti

Simulation and Numerical Modeling Team

Advanced Manufacturing Program

Automotive and Surface Transportation Research Centre

Haile Atsbha

CAE Manager

Kautex Textron Canada

(3)

Outline

Introduction: Who are we ?

Sheet/Parison Formation Prediction

-

Swell Phenomenon at the Die Exit

-

2.5D Hybrid Approach (Mathematical Model)

Kautex Textron Case Study: TSEBM Process

-

Process Parameters (VWDS, DSM, Material, ...)

-

Experimental Simulation

(4)

About NRC

• 2016-17 budget: $1B

• Over 4,000 employees and

650 volunteer and independent visitors

• 25 Government Research Facilities: Involved in a wide variety of

disciplines and support industry

IRAP

Research

facilities

Advanced Manufacturing

Material & Process

Simulation

Vehicle Light Weighting

(5)

SIGBLOW Industrial R&D Group

Blow molding simulation

research consortium, led by

NRC (1992-present)

Members include global

leaders in the automotive,

packaged goods and resin

industries

Members benefit from the

competitive advantage of

having exclusive access to

latest advances in BlowView

simulation software

(6)

SIGBLOW members by sectors

A

u

to

moti

v

e

Air duct Air duct

Seat back Fuel tank

Cooling liquid reservoir Gas can Wind shield washer reservoir

Automotive sector

Packaging

50%

25%

Other

15%

Agriculture, Aero,

Recreational, etc.

Resin

(7)

Stretch Blow Molding (SBM)

Extrusion Blow Molding (EBM)

BlowView simulation software

6

(8)

BlowView simulation software

Thermoforming

Suction Blow Molding (SuBM)

(9)

BlowView simulation software

Only dedicated software capable of

simulating and optimizing blow molding

and thermoforming processes

Enables reduced costs and production

time:

- Reduced material loss

- Reduced design to production cycle time

- Reduced production errors

- Test engineered materials for specific

applications

- Improve functional performance

Used by the world’s leading

manufacturers in the automotive and

packaging industries

(10)

Simulation of a Fuel Tank

EXTRUSION

(11)

Extrusion

•Fluid mechanics inside the die (generalized Newtonian fluid) •Time dependent

deformation (viscoelastic K-BKZ model)

•Dynamic swell and sag calculation under non-isothermal conditions •Converging and

diverging dies for small and large die heads •VWDS/SFDR/PWDS

Mold

Displacement

•All mold components are movable

(up to 15 tools)

•Friction between mold components and polymer melt (contact algorithm) •Heat transfer analysis

between mold and polymer melt

Inflation

•Multilayer viscoelastic membrane finite elements •K-BKZ constitutive law used for stress-strain deformation for each layer •Large deformation

capabilities

•Heat transfer analysis between polymer melt/mold and polymer/air •Contact between polymer/cavity and polymer /flash

Part Cooling

And Warpage

•In-mold and out-of-mold cooling •Calculation of residual stresses

•Shrinkage and warpage induced deformation •De-flashing capabilities

Thickness

Mapping

•Part/Flash weight calculation •Thickness distribution exported for structural analysis •Ansys •ABACUS •Ideas •LS-DYNA •PAM-CRASH •PATRAN

Extrusion Blow Molding

(12)

Parison Extrusion

Stretch Pins and Pinch Plates Closing

Mold Closing, Inflation, and Cooling

50 s 58 s 66 s 74 s 82 s 90 s 98 s 106 s 114 s 122 s 130 s recoiled 0 s 131.0 s 131.4 s 131.8 s 132.0 s 132.4 s 132.6 s 132.8 s 133.0 s 133.2 s 130.6 s 133.6 s 133.8 s 134.0 s 134.2 s 135.2 s 136.2 s 137.2 s 138.2 s 178.2 s 133.4 s 218.2 s 258.2 s 298.2 s mapping

(13)

Flow in the

Die

(Carreau)

a

/

)

1 n

(

a

T

0 A

[

1 (

A

)

]

)

T

,

(



















wall

front

2h

Fluid

Mechanics

Solid

Mechanics

+

Phenomenological Model

Parison

Formation

(K-BKZ)

Str

es

s

le

v

el

(14)

(15)

Die Option

Thickness Profile

Die Geometry

Parison/Part Thickness

VWDS

• Vertical Wall Distribution System

• Manipulate mandrel opening (i.e., die gap) vs. time

PWDS

• Partial Wall Distribution System • Manipulate stroke position vs.

time

• For producing non-symmetrical parts or square bottles

SFDR

• Static Flexible Deformable Ring • Manipulate stroke positions to

create a circumferential variation in the thickness at specific angular position along the parison length

DSM

• Die Slide Motion

• Manipulate slide position vs. time 180° 0° 90° 270° 180° 0° 90° 270° 0° - 30° 220° - 250° 0% Open 50% Open 270o 205o 270o 235o 220o 205o

EBM Parison Shaping Options

(16)

Parison Length Optimization

VWDS Optimization

+

PWDS or DSM Optimization

Fully Automatic

No Yes

SFDR ?

Yes

VWDS ?

No 9 8 7 6 5 4 3 2 1

VWDS Programming Profile

Die Points 270o 205o 270o 235o 220o 205o

SFDR Programming Profile

Average inflated parison thickness for each die point

Stop

Die Shaping Optimization

(17)

2.5 mm 9.4 mm

VWDS

0.63 3.02 mm

VWDS+PWDS

2.6 mm 9.7 mm

0.51 3.03 mm

VWDS+SFDR

2.4 mm 12.3 mm

0.45 3.06 mm

VWDS+SFDR+PWDS

2.8 mm 12.0 mm

0.4 3.1 mm

Initial Design

6.8 mm

Std. Dev. ():

0.83 Avg. Thick:

3.38 mm

0.5 mm 5 mm Target 3 mm

EBM Optimization of a Jerry Can

(18)

19.9 kg

Iteration #1

18.7 kg

Iteration #3

17.6 kg

Iteration #6

2.98 13.16

Initial Design

21.7 kg

3.30% EvOH

10.2 mg/day

3.6% EvOH

9.98 mg/day

3.81% EvOH

9.98 mg/day

0.3% EvOH

90.8 mg/day

3.21 12.0 Target 3.4mm Target 10mg/day

EBM Optimization of a PFT

(19)

3.81% EvOH

9.98 mg/day

0.3% EvOH

90.8 mg/day

3.21 12.0

Final Design

2.98 13.16

Initial Design

17.6 kg

21.7 kg

Reduction of Fuel

Tank Emissions

Part

Weight Optimization

EBM Optimization of a PFT

(20)

Environmentally Friendly

Fuel Tanks

(21)

MODELLING EXTRUSION AND

SHEET FORMATION

(22)

Flow in the

Die

(Carreau)

a

/

)

1 n

(

a

T

0 A

[

1 (

A

)

]

)

T

,

(



















wall

front

2h

Fluid

Mechanics

Solid

Mechanics

+

Phenomenological Model

Parison

Formation

(K-BKZ)

Str

es

s

le

v

el

2.5D Hybrid Approach

Fluid Mechanics/Solid Mechanics





                                      





qId a e I t I t c t c t d k t k k k t k 1 1 3 ₁ 1 ₂ 1 ( )/ ( ) ( , ) ( ) ( , ) ( , ) ( , )

(23)

2.5D Hybrid Approach

Fluid Mechanics/Solid Mechanics

2.5D Flow in the Die

- 2.5D Generalized-Newtonian (Carreau)

- Hele-Shaw Lubrication Theory

- Energy Equation

Solver

- Flow Kinematics

- Flow Temperature

- Shear Rate History

After Emerging the Die

- Relieve Initial Stress

- 2.5 D Solid Mechanics FE

- Constitutive Law(KBKZ)

- Swell: Width (small)

- Swell: Thickness

Flow Stresses

- Tracking



Deformation History

- An Appropriate Constitutive Law

- WLF Temperature Shift

- Initial Stress

Phenomenological

Preliminary:

Thickness, Diameter Swell

NRC’s papers on swell model:

1) Azizeh-Mitra Yousefi, Paul Collins, Stephanie Chang, Robert DiRaddo, Polym. Eng. Sci., 47, 1 (2007) 2) Azizeh-Mitra Yousefi, Jaap den Doelder, Marc-André Rainville, Kurt Koppi, Polym. Eng. Sci. (2009) 3) Azizeh-Mitra Yousefi, Haile Atsbha, Polym. Eng. Sci., (2009)

(24)

X

Width

₁

Y

₁

Y

₂

Y

₃

Y

_n W H W H W H W H W H W H

Flash Area

S

₁

S

₂

S

₃

S

₄

S

₁₃

S

₁₄

Weight

₁

Weight

₂

Weight

₃

Weight

₄

Weight

₁₃

Weight

₁₄

Video Test

Measure :

Width , Y (Die)

W H W H W H W H W H W H W H W H

S

₅

S

₆

S

₈

S

₉

S

₁₀

S

₁₁

S

₁₂

Weight

₅

Weight

₆

Weight

₇

Weight

₈

Weight

₉

Weight

₁₀

Weight

₁₁

Weight

₁₂

H ≈ 50 mm

Width

₂

Width

₃

X

Width

_n

S

₇

Phenomenological Model Calibration

Experimental Validation (Kautex Textron)

Pinch-Off Test

Measure :

Segment Area, Weight

(25)

Flow Rate per Sheet = 200 kg/h : Die Gap= 12 mm

1.0

1.2

1.4

1.8 2.2 m

1.0

1.2

1.4

1.8 2.2 m

Simulation Results

Total Sheet Width & Weight Distribution

(26)

Processing Conditions:

Material:

Lupolen 4261A +

EVOH

Total Mass Flow:

690 Kg/hr

Extrusion Time:

82 sec

Blow Time:

27 sec

Total Shot Weight:

15.7 Kg

Tank Weight :

7.05 - 7.1 Kg

Flash Weight:

8.65 – 8.7 Kg

Validation on an Industrial Part

(Kautex Textron)

Upper Shell (Z+) Lower Shell (Z-)

Middle Tool

(27)

Validation on an Industrial Part

Measured Thickness - Upper Shell

34

(28)

Validation on an Industrial Part

Measured Thickness - Lower Shell

(29)

Upper Shell (Z+)

Lower Shell (Z-)

Measured

Simulation

Measured

Simulation

Validation on an Industrial Part

Thickness Comparsion (16% Shrinkage)

(30)

Validation on an Industrial Part

Part Weight Comparison

Measured

Predicted

Tank Weight

7.05 - 7.1 Kg

6.94 Kg

(31)

Conclusion

BlowView is a useful tool for predicting complex

parison and sheet formation for EBM and TSEBM

processes;

Entire processing steps are predicted using

BlowView;

Intensive validation studies are conducted with

industrial partners;

Optimization, warpage and permeability packages

as well as large material database are available.

(32)