Structural thermoplastic lightweight design for automotive mass production

Compression molding of UD tapes and LFT

S. Baumgärtner1, T.Huber1, F. Henning1,2

1 Fraunhofer Institute for Chemical Technology (ICT) 2 Karlsruhe Institute of Technology (KIT)

17th-Annual SPE Automotive Composites Conference & Exhibition (ACCE) – September 6-8, 2017

© Fraunhofer ICT

BMBF Lighthouse Project SMiLE

UD tape processing at Fraunhofer ICT

Process development

Direct LFT

Combined process (UD tape and LFT)

Transfer to large demonstrator part: Composite floor structure

2

Agenda

31.07.2017

© Fraunhofer ICT

BMBF Lighthouse Project SMiLE

UD tape processing at Fraunhofer ICT

Process development

Direct LFT

Combined process (UD tape and LFT)

Transfer to large demonstrator part: Composite floor structure

3

Agenda

31.07.2017

© Fraunhofer ICT

Systemintegrativer Multi-Material-Leichtbau für die Elektromobilität Partners

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University/ institutes Industrial partners

Funding ref.: 03X3041P

© Fraunhofer ICT

Holistic hybrid multi-material design

Further development of nonferrous metals (aluminum, magnesium)

Development of low-temperature cataphoretic painting (KTL) and optimized aluminum alloys

Composite floor structure (thermoset and thermoplastic composites)

Joining technologies for multi-material design

Assembly of demonstrator car body and life cycle assessment

Range: approx. 200 km

13 battery modules with 2.7 kWh each

> 300 parts per day

SMiLE lightweight car body for e-mobility

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© Fraunhofer ICT

Holistic lightweight approach

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In order to develop high-performance lightweight solutions which can be manufactured on an industrial scale, it is essential to concentrate and connect competences in the fields of methods, materials and production

C O M P O S I T E

S O L U T I O N S

P R O C E S S E S

Thermoplastic

RTM-/RIM

SMC

Fiber spraying

Tapes

Thermoset

T-RTM LFT

Preforming

Inject. molding

M E T H O D S

Engineering/Design

Structure Simulation

Process Simulation

M A T E R I A L S

Fiber

Matrix

Additives, Filler, (…)

© Fraunhofer ICT

BMBF Lighthouse Project SMiLE

UD tape process ing at Fraunhofer ICT

Process development

Direct LFT

Combined process (UD tape and LFT)

Transfer to large demonstrator part: Composite floor structure

7

Agenda

31.07.2017

© Fraunhofer ICT

Thermoplastic tape processing at Fraunhofer ICT

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Fiberforge 4.0 (automated tapelaying)

Tailored blank (stacked)

Tailored blank (consolidated)

Fibercon (radiation-induced vacuum consolidation)

UD tape

© Fraunhofer ICT

The efficient route to tailored blanks made of UD tapes

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Fiberforge 4.0 available at ICT, Pfinztal

© Fraunhofer ICT 10 31.07.2017

The efficient route to tailored blanks made of UD tapes

Fibercon (a.k.a. radiation-induced vacuum consolidation) available at ICT, Pfinztal

© Fraunhofer ICT

BMBF Lighthouse Project SMiLE

UD tape processing at Fraunhofer ICT

Process development

Direct LFT

Combined process (UD tape and LFT)

Transfer to large demonstrator part: Composite floor structure

11

Agenda

31.07.2017

© Fraunhofer ICT

LFT

Process development: Local advanced tailored long fiber thermoplastics (LFT)

Benefit of LFT compression molding:

Economic process for large parts with low cycle times

Benefit of advanced LFT compression molding:

Use of engineering thermoplastics enables new applications (higher loads, chemical resistance, higher temperature conditions)

Benefit of advanced tailored LFT:

Continuous-fiber reinforcements in main load path enable structural applications

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UD tape

LFT

UD tape

Side view Cross-section

© Fraunhofer ICT

Goal

Further reduction of part weight

Reduction of wall thickness through use of continuous-fiber-reinforced tapes

Only local use of LFT to reinforce the structure, and to avoid buckling of tape laminate and add functions (inserts, …)

Development of new process local advanced tailored LFT

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Process development: Local advanced tailored long fiber thermoplastics (LFT)

UD tape

LFT

LFT

UD tape

LFT

LFT

Side view Cross section

© Fraunhofer ICT

Process concept

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LFT UD tape

displaceable cavity rib FP

FV

FP: press force FV: press force of displaceable cavity

© Fraunhofer ICT

Process concept (animation)

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FP

FV

LFT UD tape

© Fraunhofer ICT

Process concept (test part)

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0°

90°

370 mm LFT

5 mm overlap (tape + LFT)

150 mm tape

400 mm

120 mm

Mold temp.: 80 °C

D-LFT: PA6 (BASF-B3K) + 40 wt.-% e-glass fiber

UD tapes : BASF Ultratape B3WC12 (PA6 with 60 wt.-% carbon fibers)

13 layers with total thickness of 2.1 mm

© Fraunhofer ICT

BMBF Lighthouse Project SMiLE

UD tape processing at Fraunhofer ICT

Process development

Direct LFT

Combined process (UD tape and LFT)

Transfer to large demonstrator part: Composite floor structure

17

Agenda

31.07.2017

© Fraunhofer ICT

D-LFT Process

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LFT plastificate (open transfer)

Inline compounder

Compression molding

Mixing extruder with die

Polymer + additives

© Fraunhofer ICT

D-LFT form filling parameters

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Parameter

Width of initial charge 175 mm

Length of initial charge 170 mm

Height of initial charge (nozzle setup) 12 mm

Press force / Cavity pressure 3000 kN / 200 bar

Tool temperature 80 °C

© Fraunhofer ICT

D-LFT form filling

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© Fraunhofer ICT

D-LFT form filling

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© Fraunhofer ICT

D-LFT form filling

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© Fraunhofer ICT

D-LFT form filling

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© Fraunhofer ICT

D-LFT form filling

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© Fraunhofer ICT

D-LFT form filling

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© Fraunhofer ICT

D-LFT form filling

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© Fraunhofer ICT

D-LFT form filling

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© Fraunhofer ICT

Rib filling influencing parameters

LFT temperature (not varied)

Position, size and direction of initial charge

Closing profile

Mold temperature

Press force

Tape temperature

80 °C

130 °C

275 °C (before transfer)

Combined process (UD tape and LFT)

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© Fraunhofer ICT

BMBF Lighthouse Project SMiLE

UD tape processing at Fraunhofer ICT

Process development

Direct LFT

Combined process (UD tape and LFT)

Transfer to large demonstrator part: Composite floor structure

29

Agenda

31.07.2017

© Fraunhofer ICT

Tape temperature above crystallization

Computer tomography

SEM

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Melted UD tape gets infiltrated/ misaligned if LFT flows against flank

Mold cavity

LFT

Initial tape position

LFT

10 mm

2 mm

© Fraunhofer ICT

Tape temperature below melting temperature

Computer tomography

SEM

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LFT

LFT LFT

Solid UD tape stays in position. Interface strength?

2 mm 2 mm

10 mm

© Fraunhofer ICT

Shear edge test

Preparation

Testing

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Press plates F

Lateral support

F F

Testing method developed by: KIT Institut für Angewandte Materialien - Werkstoffkunde (IAM-WK)

Source: K.A. Weidenmann, L. Baumgärtner, B. Haspel: The Edge Shear Test - An Alternative Testing Method for the Determination of the Interlaminar Shear Strength in Composite Materials, doi:10.4028/www.scientific.net/MSF.825-826.806

31.07.2017

© Fraunhofer ICT

Shear edge test Preparation

Results

Interface strength at 80 °C below 10 MPa

Interface strength at higher temperatures:

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0

10

20

30

40

50

60

70

1 2 3 4 5 6 7 8 9 10 11

Sh

ea

r st

ren

gth

[M

Pa

]

Position

[90/0] 2mm 275°C

0

10

20

30

40

50

60

70

1 2 3 4 5 6 7 8 9 10 11

Sh

ea

r st

ren

gth

[M

Pa

]

Position

[90/0] 2mm 130°C

Similar interface strength if interface temperature is at least 130 °C

© Fraunhofer ICT 34 31.07.2017

Transfer into more complex ribs

30 mm

120 mm

30 mm

Results were used for calibration of the moldflow simulation

© Fraunhofer ICT

BMBF Lighthouse Project SMiLE

UD tape processing at Fraunhofer ICT

Process development

Direct LFT

Combined process (UD tape and LFT)

Transfer to large demonstrator part: Composite floor structure

35

Agenda

31.07.2017

© Fraunhofer ICT

AP3 Demonstrator: Composite floor structure

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Aluminum profiles LFT-D including metallic inserts

UD tape

One-shot hybrid thermoplastic composite part

~1300 mm

~1300 m

m

© Fraunhofer ICT

Structural and crash simulation (BASF Ultrasim)

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Responsible project partner: Sebastian Ebli, BASF

© Fraunhofer ICT

Process simulation: Draping simulation (Abaqus-based)

Sequential forming of UD tape

Responsible project partner: Dominik Dörr, KIT FAST

31.07.2017

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© Fraunhofer ICT

Process simulation: Draping simulation (Abaqus-based)

Optimization of net shape tapelaying

Responsible project partner: Dominik Dörr, KIT FAST

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© Fraunhofer ICT

Process simulation: Form filling (moldflow)

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Responsible project partner: Martin Hohberg, KIT FAST

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© Fraunhofer ICT

Summary

Process was developed and feasibility could be demonstrated

Formfilling was optimized by variation of process parameters

Hollistic development of demonstrator part

To be continued…

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© Fraunhofer ICT

Thank you for your attention!

Contact details M.Eng Sebastian Baumgärtner Team Leader Thermoplastic Processing SMiLE WP3 Leader – Thermoplastic Composites Fraunhofer-Institut für Chemische Technologie ICT Joseph-von-Fraunhofer-Str. 7, 76327 Pfinztal, Germany Tel.: +49 721 4640-830 Fax: +49 721 4640-800-830 Sebastian.Baumgaertner@ict.fraunhofer.de www.ict.fraunhofer.de

31.07.2017