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Otto Gloeckel-Straße 2, A-8700 Leoben, Tel.: +43 3842 402 3501 [email protected] www.kunststofftechnik.at Ass.Prof. Dr. Thomas Lucyshyn 24 th April 2014 Influence of material data on injection moulding simulation Application examples TRAINING IN THE FIELD OF POLYMER MATERIALS / PLASTICS

TRAINING IN THE FIELD OF POLYMER MATERIALS / … · Source: T. Kisslinger: Einfluss der thermischen Stoffdaten auf Berechnungsergebnisse in Moldflow Plastics Insight (MPI), Studienarbeit

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Text of TRAINING IN THE FIELD OF POLYMER MATERIALS / … · Source: T. Kisslinger: Einfluss der thermischen...

  • Otto Gloeckel-Strae 2, A-8700 Leoben, Tel.: +43 3842 402 3501

    [email protected]

    www.kunststofftechnik.at

    Ass.Prof. Dr. Thomas Lucyshyn 24th April 2014

    Influence of material data on injection moulding simulation

    Application examples

    TRAINING IN THE FIELD OF POLYMER MATERIALS / PLASTICS

  • www.kunststofftechnik.at Thomas Lucyshyn 2

    Content

    Introduction

    Melt Flow Rate (MFR) as reference value for viscosity

    Pressure dependence of viscosity

    Transition temperature

    Thermal conductivity and specific heat capacity

    pvT-data at different cooling rates

    Summary

  • www.kunststofftechnik.at Thomas Lucyshyn 3

    Content

    Introduction

    Melt Flow Rate (MFR) as reference value for viscosity

    Pressure dependence of viscosity

    Transition temperature

    Thermal conductivity and specific heat capacity

    pvT-data at different cooling rates

    Summary

  • www.kunststofftechnik.at Thomas Lucyshyn 4

    Required material data

    Viscosity as a function of

    Shear rate, temperature and optionally pressure

    Transition temperature Ttrans Thermal conductivity (ideally temperature dependent)

    Specific heat (ideally temperature dependent)

    pvT-data

    Mechanical properties

    Youngs modulus, Poisson ratio, shear modulus, coefficient of linear thermal expansion

    Fibre properties

  • www.kunststofftechnik.at Thomas Lucyshyn 5

    Material data for injection moulding simulation

    Source: Internet

  • www.kunststofftechnik.at Thomas Lucyshyn 6

    Content

    Introduction

    Melt Flow Rate (MFR) as reference value for viscosity

    Pressure dependence of viscosity

    Transition temperature

    Thermal conductivity and specific heat capacity

    pvT-data at different cooling rates

    Summary

  • www.kunststofftechnik.at Thomas Lucyshyn 7

    Measuring method of MFR

    Source according to: Waner, E.: Rheologische Grundlagen fr die Auslegung von Extrusionswerkzeugen, VDI-Praktikum: Werkzeugauslegung mit Excel, Paderborn, 2003.

    Weight

    Piston

    Sample

    Heating

    Nozzle Shear rate:

    Viscosity:

    Shear stress: Weight (mass):

    MFR: Melt mass flow rate in g/10min

    MVR: Melt volume flow rate in cm/10min

    Nozzle:

  • www.kunststofftechnik.at Thomas Lucyshyn 8

    MFR as reference value for viscosity?

  • www.kunststofftechnik.at Thomas Lucyshyn 9

    MFR for comparing materials?

    MFR of A = MFR of B Rheological behaviour of A = Rheological behaviour of B?

    MFR

    log

    log

    Material A Material B

  • www.kunststofftechnik.at Thomas Lucyshyn 10

    Example: pressure calculation at same MFR

    2 unfilled POM-grades of same supplier

  • www.kunststofftechnik.at Thomas Lucyshyn 11

    Viscosity curves of the two POM-grades

  • www.kunststofftechnik.at Thomas Lucyshyn 12

    Part for simulation

    Square box 100 x 100 x 40 mm (1 mm wall thickness)

    Hot runner with central gate at the bottom

  • www.kunststofftechnik.at Thomas Lucyshyn 13

    Pressure at swich over point (filling pressure)

    Hostaform s9363 Celcon M50-14

    1185 bar 1476 bar

    25%

  • www.kunststofftechnik.at Thomas Lucyshyn 14

    Content

    Introduction

    Melt Flow Rate (MFR) as reference value for viscosity

    Pressure dependence of viscosity

    Transition temperature

    Thermal conductivity and specific heat capacity

    pvT-data at different cooling rates

    Summary

  • www.kunststofftechnik.at Thomas Lucyshyn 15

    Cross-WLF-equation in Moldflow

  • www.kunststofftechnik.at Thomas Lucyshyn 16

    Cross-WLF-equation in Moldflow

    n

    1

    0

    0

    1

    (8)

    *TTA

    *TTAexpD

    2

    110

    pDD*T 32

    pDAA ~ 322

    Pressure dependence!

    Approx. 8.800 thermoplastics in Moldflow 2014, of which about 100 materials with D3

  • www.kunststofftechnik.at Thomas Lucyshyn 17

    Cross-WLF-equation in Moldflow

    CB1

    A

    n

    1

    0

    0

    1

    (8)

    0

    0

    *

    1-n temperature

    pressure

  • www.kunststofftechnik.at Thomas Lucyshyn 18

    Part: thin walled bush

    Wall thickness about 0,4 to 0,8 mm

    Injection pressure at the injection moulding machine: 2400 bar

  • www.kunststofftechnik.at Thomas Lucyshyn 19

    Measuring results of pressure dependent viscosity

    1000 bar

    1 bar

    Vis

    cosi

    ty in P

    a*s

    Shear rate in s-1

  • www.kunststofftechnik.at Thomas Lucyshyn 20

    Calucations with and without pressure dependence

    Without pressure dependence With pressure dependence

  • www.kunststofftechnik.at Thomas Lucyshyn 21

    Pressure at switch-over point (injection pressure)

    1284 bar

    Without pressure dependence

    2368 bar

    With pressure dependence

    85%

  • www.kunststofftechnik.at Thomas Lucyshyn 22

    Content

    Introduction

    Melt Flow Rate (MFR) as reference value for viscosity

    Pressure dependence of viscosity

    Transition temperature

    Thermal conductivity and specific heat capacity

    pvT-data at different cooling rates

    Summary

  • www.kunststofftechnik.at Thomas Lucyshyn 23

    Transition temperature (No-Flow)

    Experimental determination

    DSC-Measurement (Differential Scanning Calorimetry) In cooling mode at -20 K/min Determination of the onset temperature

    Capillary rheometer (not used any more) Melt polymer turn off heating piston with constant load

    squeeze out melt until strand speed = 2mm/min (equals 0,033 mm/s!)

    Further (less frequent) methods: Adapted injection moulding machine Pressure measurement at capillary rheometer Cone-plate-rheometer

  • www.kunststofftechnik.at Thomas Lucyshyn 24

    Transition temperature with DSC

    oven chamber

    DSC sample and reference

    Source:

    Mettler Toledo AG, CH

  • www.kunststofftechnik.at Thomas Lucyshyn 25

    20 40 60 80 100 120 140 160 180 2000

    10

    20

    30

    40

    50

    60

    70

    80

    H (

    mW

    )

    T (C) Hostacom BR 735 G

    Heat flow H as a function of temperature T

    PP

    cooling rate -20 K/min

    Transition temperature

    Cooling mode

    Source: T. Lucyshyn, G. Knapp, M. Kipperer, C. Holzer: Determination of the Transition Temperature at Different Cooling Rates and Its Influence on Prediction of Shrinkage and Warpage in Injection Molding Simulation. Journal of Applied Polymer Science, 2012, 123, S.1162-1168.

    Transition temp. of a semi-crystalline polymer

  • www.kunststofftechnik.at Thomas Lucyshyn 26

    Transition temperature (point of inflection)

    Cooling mode

    Source: T. Lucyshyn, G. Knapp, M. Kipperer, C. Holzer: Determination of the Transition Temperature at Different Cooling Rates and Its Influence on Prediction of Shrinkage and Warpage in Injection Molding Simulation. Journal of Applied Polymer Science, 2012, 123, S.1162-1168.

    Transition temp. of an amorphous polymer

    ABS (cooling rate -20 K/min)

  • www.kunststofftechnik.at Thomas Lucyshyn 27

    Heat flux at different cooling rates for PP

    20 40 60 80 100 120 140 160 180 2000

    10

    20

    30

    40

    50

    60

    70

    80 5 K/min

    10 K/min

    20 K/min

    40 K/min

    50 K/min

    H (

    mW

    )

    T (C) Hostacom BR 735 G

    Source: T. Lucyshyn, G. Knapp, M. Kipperer, C. Holzer: Determination of the Transition Temperature at Different Cooling Rates and Its Influence on Prediction of Shrinkage and Warpage in Injection Molding Simulation. Journal of Applied Polymer Science, 2012, 123, S.1162-1168.

  • www.kunststofftechnik.at Thomas Lucyshyn 28

    Transition temp. as a function of cooling rate for PP

    b

    transt

    TaT

    Parameter PP

    Hostacom BR 735 G

    a (minbK(1-b)) 415,4

    b (-) -0,0148

    Correlation coefficient R2

    0,983 0 10 20 30 40 50 60 70 80 90 100 110

    380

    385

    390

    395

    400

    405

    410

    Ttr

    ans (

    K)

    Hostacom BR 735 GCooling rate (K/min)

    Ttrans

    Source: T. Lucyshyn, G. Knapp, M. Kipperer, C. Holzer: Determination of the Transition Temperature at Different Cooling Rates and Its Influence on Prediction of Shrinkage and Warpage in Injection Molding Simulation. Journal of Applied Polymer Science, 2012, 123, S.1162-1168.

  • www.kunststofftechnik.at Thomas Lucyshyn 29

    Box for simulation and experiments

    100 x 100 x 40 mm

    Source: T. Lucyshyn, G. Knapp, M. Kipperer, C. Holzer: Determination of the Transition Temperature at Different Cooling Rates and Its Influence on Prediction of Shrinkage and Warpage in Injection Molding Simulation. Journal of Applied Polymer Science, 2012, 123, S.1162-1168.

  • www.kunststofftechnik.at Thomas Lucyshyn 30

    Results for warpage simulation for PP

    10 20 30 40 50 60 70 80 90 100 1100,0

    0,5

    1,0

    1,5

    2,0

    2,5

    3,0

    3,5

    4,0

    Defo

    rmation (

    %)

    Cooling rate (K/min) Hostacom BR 735 G 3D

    L1 experiment

    L2 experiment

    L3 experiment

    H1 experiment

    H2 experiment

    L1 simulation

    L2 simulation

    L3 simulation

    H1 simulation

    H2 simulation

    Box:

    1 mm wall thickness

    Source: T. Lucyshyn, G. Knapp, M. Kipperer, C. Holzer: Determination of the Transition Temperature at Different Cooling Rates and Its Influence on Prediction of Shrinkage and Warpage in Injection Molding Simulation. Journal of Applied Polymer Science, 2012, 123, S.1162-1168.

  • www.kunststofftechnik.at Thomas Lucyshyn 31

    Content

    Introduction

    Melt Flow Rate (MFR) as reference value for viscosity

    Pressure dependence of viscosity

    Transition temperature

    Thermal conductivity and specific heat capacity

    pvT-data at different cooling rates

    Summary

  • www.kunststofftechnik.at Thomas Lucyshyn 32

    Semi-crystalline thermoplastics

    0

    0,1

    0,2

    0,3

    0,4

    0 50 100 150 200 250 300 350Temperatur [C]

    W

    rme

    leit

    fh

    igk

    eit

    [W

    /mK

    ] PP

    PA

    POM

    Amorphous thermoplastics

    0

    0,1

    0,2

    0,3

    0 50 100 150 200 250 300 350Temperatur [C]

    W

    rme

    leit

    fh

    igk

    eit

    [W

    /mK

    ]

    PS

    ABS

    PC

    Thermal conductivity

    Source: T. Kisslinger: Einfluss der thermischen Stoffdaten auf Berechnungsergebnisse in Moldflow Plastics Insight (MPI), Studienarbeit am Institut fr Kunststoffverarbeitung, Montanuniversitt Leoben, 2007.

    Th

    erm

    al

    co

    nd

    ucti

    vit

    y (

    W/m

    K)

    Temperature (C)

    Th

    erm

    al

    co

    nd

    ucti

    vit

    y (

    W/m

    K)

    Temperature (C)

  • www.kunststofftechnik.at Thomas Lucyshyn 33

    Specific heat capacity (cp)

    Source: T. Kisslinger: Einfluss der thermischen Stoffdaten auf Berechnungsergebnisse in Moldflow Plastics Insight (MPI), Studienarbeit am Institut fr Kunststoffverarbeitung, Montanuniversitt Leoben, 2007.

    0

    4000

    8000

    12000

    16000

    0 50 100 150 200 250 300 350Temperatur [C]

    Cp

    [J

    /Kg

    K]

    PP

    PA

    POM

    0

    500

    1000

    1500

    2000

    2500

    0 50 100 150 200 250 300 350Temperatur [C]

    Cp

    [J

    /Kg

    K]

    PS

    ABS

    PC

    Semi-crystalline thermoplastics

    Amorphous thermoplastics

    cp (

    J/k

    gK

    )

    cp (

    J/k

    gK

    )

    Temperature (C) Temperature (C)

  • www.kunststofftechnik.at Thomas Lucyshyn 34

    Single values temperature dependent values

    Single value of specific heat at melt temperature (example for PP)

    Single value of thermal conductivity at melt temperature (example for PP)

    0

    0,05

    0,1

    0,15

    0,2

    0,25

    0,3

    0 50 100 150 200 250 300

    Temperatur [C]

    W

    rme

    leit

    fh

    igk

    eit

    [W

    /mK

    ]

    0

    4000

    8000

    12000

    16000

    0 50 100 150 200 250 300

    Temperatur [C]

    Cp

    [J

    /Kg

    K]

    Source: T. Kisslinger: Einfluss der thermischen Stoffdaten auf Berechnungsergebnisse in Moldflow Plastics Insight (MPI), Studienarbeit am Institut fr Kunststoffverarbeitung, Montanuniversitt Leoben, 2007.

    cp (

    J/k

    gK

    ) T

    he

    rma

    l co

    nd

    ucti

    vit

    y (

    W/m

    K)

    Temperature (C)

    Temperature (C)

  • www.kunststofftechnik.at Thomas Lucyshyn 35

    Influence on cycle time

    Temperature of hottest region in part over time

    Time to reach ejection temperature evaluated

    Investigated region of part

    Source: T. Kisslinger: Einfluss der thermischen Stoffdaten auf Berechnungsergebnisse in Moldflow Plastics Insight (MPI), Studienarbeit am Institut fr Kunststoffverarbeitung, Montanuniversitt Leoben, 2007.

  • www.kunststofftechnik.at Thomas Lucyshyn 36

    Influence on cycle time

    Example PP, 3 mm wall thickness

    Source: T. Kisslinger: Einfluss der thermischen Stoffdaten auf Berechnungsergebnisse in Moldflow Plastics Insight (MPI), Studienarbeit am Institut fr Kunststoffverarbeitung, Montanuniversitt Leoben, 2007.

    Tim

    e (

    s)

    Mesh variations

  • www.kunststofftechnik.at Thomas Lucyshyn 37

    Influence on cycle time

    Example PS, 3 mm wall thickness

    18,08

    22,1621,65

    17,28

    20,4120,63

    25,02

    29,02

    0,00

    5,00

    10,00

    15,00

    20,00

    25,00

    30,00

    35,00

    PS Fusion 3mm PS 3D 3mm

    Berechnungsvarianten

    Ze

    it [

    se

    c]

    (T) cp(T)

    (T) cp

    cp(T)

    cp

    Source: T. Kisslinger: Einfluss der thermischen Stoffdaten auf Berechnungsergebnisse in Moldflow Plastics Insight (MPI), Studienarbeit am Institut fr Kunststoffverarbeitung, Montanuniversitt Leoben, 2007.

    Tim

    e (

    s)

    Mesh variations

  • www.kunststofftechnik.at Thomas Lucyshyn 38

    Content

    Introduction

    Melt Flow Rate (MFR) as reference value for viscosity

    Pressure dependence of viscosity

    Transition temperature

    Thermal conductivity and specific heat capacity

    pvT-data at different cooling rates

    Summary

  • www.kunststofftechnik.at Thomas Lucyshyn 39

    Semi-crystalline polymer

    Temperature (C)

    Specific volume (cm/g)

    pvT-data

    Amorphous polymer

    Transition temperature

    Source according to: Kennedy, P.: Flow Analysis of Injection Molds; Carl Hanser Verlag, Mnchen, 1995.

    melt

    solid

    melt

    solid

    Temperature (C)

    Specific volume (cm/g)

    Transition temperature

  • www.kunststofftechnik.at Thomas Lucyshyn 40

    Standard measurement method for pvT-data

    m

    rlT,pv

    2

    Cooling rate of approx.

    0,1 K/s (6 K/min)

  • www.kunststofftechnik.at Thomas Lucyshyn 41

    high cooling rate (hcr) pvT-device

    Stroke transducer

    Thermocouple Ejector piston

    Measuring cell

    Polymer sample

    Cooling channels

    Cooling channels

    Piston

    IR-sensor

    Oven

    IR-sensor

    Pressure transducer

    in hydraulic system

    Cooling rates up to

    15 K/s

    Source: T. Lucyshyn: Messung von pvT-Daten bei prozessnahen Abkhlraten und deren Einfluss auf die Simulation von Schwindung und

    Verzug mit Moldflow Plastics Insight, Dissertation an der Montanuniversitt Leoben, 2009.

  • www.kunststofftechnik.at Thomas Lucyshyn 42

    Results of hcr-pvT-device for ABS

    0,92

    0,94

    0,96

    0,98

    1,00

    1,02

    1,04

    1,06

    0 50 100 150 200 250

    Temperatur in C

    Sp

    ezif

    isc

    he

    s V

    olu

    me

    n in

    cm

    /g

    200 bar hcr-pvT

    400 bar hcr-pvT

    600 bar hcr-pvT

    800 bar hcr-pvT

    200 bar MPI

    400 bar MPI

    600 bar MPI

    800 bar MPI

    ABS

    Ca. 13 K/s

    Ca. 0,1 K/s

    2,3 mm sample

    Source: T. Lucyshyn: Messung von pvT-Daten bei prozessnahen Abkhlraten und deren Einfluss auf die Simulation von Schwindung und

    Verzug mit Moldflow Plastics Insight, Dissertation an der Montanuniversitt Leoben, 2009.

    Temperature (C)

    Sp

    ecif

    ic v

    olu

    me

    (cm

    /g

    )

  • www.kunststofftechnik.at Thomas Lucyshyn 43

    Results of hcr-pvT-device for PP

    Ca. 15 K/s

    Ca. 0,1 K/s

    0,94

    0,96

    0,98

    1,00

    1,02

    1,04

    1,06

    1,08

    1,10

    1,12

    0 50 100 150 200 250

    Temperatur in C

    Sp

    ez. V

    olu

    me

    n in

    cm

    /g

    400 bar hcr-pvT

    600 bar hcr-pvT

    800 bar hcr-pvT

    400 bar MPI

    600 bar MPI

    800 bar MPI

    PP

    2 mm Probe

    Source: T. Lucyshyn: Messung von pvT-Daten bei prozessnahen Abkhlraten und deren Einfluss auf die Simulation von Schwindung und

    Verzug mit Moldflow Plastics Insight, Dissertation an der Montanuniversitt Leoben, 2009.

    Temperature (C)

    Sp

    ecif

    ic v

    olu

    me

    (cm

    /g

    )

  • www.kunststofftechnik.at Thomas Lucyshyn 44

    Simulation results for ABS

    0,0

    0,2

    0,4

    0,6

    0,8

    1,0

    1,2

    1,4

    1,6

    1,8

    2,0

    L1 L2 L3 H1 H2

    Vergleichsmae

    De

    form

    ati

    on

    in

    %

    Standard pvT

    hcr-pvT

    Experiment

    ABS, 3D-Model

    Source: T. Lucyshyn: Messung von pvT-Daten bei prozessnahen Abkhlraten und deren Einfluss auf die Simulation von Schwindung und

    Verzug mit Moldflow Plastics Insight, Dissertation an der Montanuniversitt Leoben, 2009.

    Reference dimensions

  • www.kunststofftechnik.at Thomas Lucyshyn 45

    Simulation results for PP

    PP, 3D-Model

    0,0

    0,2

    0,4

    0,6

    0,8

    1,0

    1,2

    1,4

    1,6

    1,8

    2,0

    L1 L2 L3 H1 H2

    Vergleichsmae

    De

    form

    ati

    on

    in

    %

    Standard pvT

    hcr-pvT

    Experiment

    Source: T. Lucyshyn: Messung von pvT-Daten bei prozessnahen Abkhlraten und deren Einfluss auf die Simulation von Schwindung und

    Verzug mit Moldflow Plastics Insight, Dissertation an der Montanuniversitt Leoben, 2009.

    Reference dimensions

  • www.kunststofftechnik.at Thomas Lucyshyn 46

    Content

    Introduction

    Melt Flow Rate (MFR) as reference value for viscosity

    Pressure dependence of viscosity

    Transition temperature

    Thermal conductivity and specific heat capacity

    pvT-data at different cooling rates

    Summary

  • www.kunststofftechnik.at Thomas Lucyshyn 47

    Summary 1

    Complex material data required for simulation

    Melt Flow Rate (MFR) as reference value for viscosity?

    Good orientation for limitation of potential similar materials

    Important: compare viscosity curves!

    Example: pressure difference of 25% at same MFR

    Pressure dependence of viscosity

    Viscosity increases with increasing pressure

    Especially important for thin walled parts

    Relevant at expected injection pressures > 1000 bar

    Example: pressure difference of 85%

  • www.kunststofftechnik.at Thomas Lucyshyn 48

    Summary 2

    Transition temperature

    Determined with DSC measurement

    Cooling rate has influence on transition temperature

    Transition temperature has influence on warpage results

    Temperature dependent thermal data

    Significant differences between single point data and temperature dependent data

    Especially cycle time differs by up to 15%

    pvT-data

    Cooling rate has influence on pvT-curves

    Improved shrinkage simulation with pvT-data obtained at process near cooling rates

  • www.kunststofftechnik.at Thomas Lucyshyn 49

    Thank you for your attention!

    Contact: Ass.Prof. Dr. Thomas Lucyshyn Chair of Polymer Processing Montanuniversitaet Leoben Otto Gloeckel-Str. 2 8700 Leoben 03842 / 402 3510 [email protected]