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Spring Semester 2017131-5048-00L Manufacturing of Polymer Composites

Joanna Wong 16 May 2016

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Processing of High Performance Thermoplastic Composites

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Reorient your focus

Different material systems different properties + different processing conditions

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Spaghetti Fishing net

Thermoplastic composites

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Introduction to Thermoplastic Composites Thermoplastic Matrix Materials Basics of Thermoplastic Composite Processing Intermediate Materials for Thermoplastic Composites Processes for Thermoplastic Composites Welding Recycling

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Outline

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Basics of Processing of Thermoplastic composites

Quelle: Gutowski, T.G.: Advanced Composites Manufacturing; John

Wiley & Sons, Inc. New York 1997

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Processing temperatures

• High temperatures are required to reduce melt viscosity for easier processing

• BUT, high temperatures cause the polymers to degrade due to thermal oxidation

• Strategy: To heat material quickly and minimize time at high temperatures

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Comparison of different heating strategies

Quelle: Schmidt, R.: Einsatz von Hochleistungslasern für die Fertigung von Faserverbundbauteilen mit thermoplastischer Matrix im Wickelverfahren; VDI-Verlag, Düsseldorf 1994

Very good good medium mediocre bad

Requirements

Speed

TemperaturedistributionControllability

Compact setup

Flexibility

Costs

Hot gas (Air) Hot gas (Inert)

Infrared

HeatConduction

LaserHot platte

Heat radiationHeat Convection

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Selection of possible heating strategiesObserved effects RemarksHeating method

Quelle: Schmidt, R.: Einsatz von Hochleistungslasern für die Fertigung von Faserverbundbauteilen mit thermoplastischer Matrix im Wickelverfahren; VDI-Verlag, Düsseldorf 1994

Measures to avoid contamination and impurities are required (films)

Reduced oxidation risks by use of inert gases

Oxidation effects due to open flame

Useful control only available using short-wave IR emitters

Ideal energy source

Suitable for all materials

High energy density

Limited efficiency with transparent materials

Large heating systems with additional pressure application

Large temporal inertia of sysstems

Constant processing speeds are desirable

Constant processing speeds must be observed

Problems with thick laminates

Elaborate set up required

Possible to transmit radiation through optical fibre

Contact heating

Hot gas

Open flame

IR-radiation

CO2-Laser

Nd:Yag-Laser

Conduction Convection Radiation

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Processing of Thermoplastic composites: Main steps

Quelle: Gutowski, T.G.: Advanced Composites Manufacturing; John

Wiley & Sons, Inc. New York 1997

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Consolidation mechanisms

compaction

Autohesion

Resin flowmechanisms

100% Contact

100% Autohesion Fiber preform is

compressed

Time (log)

Thic

knes

s

ImpregnationMain consolidation

process

Matrix permeation

Pressure

Fibers

tdpKz P22

2

32 14 f

ffp k

rK

z

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Coomingled yarns: Schematic of the consolidation process

N Bernet, V Michaud, P.-E Bourban, J.-A.E Månson, Commingled yarn composites for rapid processing of complex shapes, Composites Part A: Applied Science and ManufacturingVolume 32, Issue 11, November 2001, Pages 1613–1626

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Evolution of the void content as a function of the consolidation time

N Bernet, V Michaud, P.-E Bourban, J.-A.E Månson, Commingled yarn composites for rapid processing of complex shapes, Composites Part A: Applied Science and Manufacturing, Volume 32, Issue 11, November 2001, Pages 1613–1626

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Flow mechanisms during forming

Quelle: Niedermeier, E.: Analyse des Diaphragmaformens kontinuierlich faserverstärkter Hochleistungsthermoplaste; VDI-Verlag, Düsseldorf 1995

Autoclave

Tapes

Press (Cons.)

Press (forming)

Diaphragm

Resinpercolation

Transverse flow

Intraplay shearing

Interply slip Rotatorysliding

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Processing of Thermoplastic composites: Main steps

Quelle: Gutowski, T.G.: Advanced Composites Manufacturing; John

Wiley & Sons, Inc. New York 1997

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Solidification

0

5

10

15

20

25

120 130 140 150 160 170 180 190 200

Temperatur [°C]

Wär

mef

luss

(End

o na

ch o

ben)

[m

178 °C

149 °C

178°C

149°C

Temperature [ ºC]

Endo

ther

mic

heat

flow

-> [m

W]

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Surface consistency after solidification

Fiber-reinforced thermoplasticsshow generally a bad surfacequality

This occurs due to:

– The difference in the thermal expansion coefficients betweenfibers and matrix

– The phase transformation ofthe matrix during solidification

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Introduction to Thermoplastic Composites Thermoplastic Matrix Materials Basics of Thermoplastic Composite Processing Intermediate Materials for Thermoplastic Composites Processes for Thermoplastic Composites Welding Recycling

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Outline

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Processing routes for high performance thermoplastic composites

Redrawn from: Manson,J.-A., in Advanced Thermoplastic Composites, (Kausch, H. H. Ed.), Hanser Publisher, Munich, 1993. The classification of the fabrication techniques has beensummarized according to Cattanach & Cogswell.J.B. Cattanach, F.N. Cogswell, Advances in thermoplastic composite fabrication technology. In: G. Pritchard Ed. Developments in Reinforced Plastics, Chapter 5. Elsevier Applied Science Publishers, London, UK, 1985

preform typeImpregnation technique• hot-melt• solution• pseudo-

thermoplastic

pre-forming technique• film stacking• fibre

hybridisation• Powder

coating

Fabrication techniquesfor themoplasticcomposites

Resin+fibre

pre-

impr

egna

tion

tech

niqu

espo

st-s

hapi

ngim

preg

natio

n

• Tape• Tow• fabric

commingled yarns

powder coated tows

prepreg sheet

woven and braided fabrics part

Matched mouldingo Platen pressingo Compression mouldingo Roll-Formingo Pultrusion

Strech-draw (stamp forming)o Hydroformingo Rubber pressingo Double-action matched-die-

moulding

Compliance mouldingo Autoclavingo Press-clave mouldingo Vacuum formingo Cushion platen mouldingo Piston matched-die mouldingo Diaphragm forming

In-Situ consolidation/laminationo Tape layingo Filament windingo Tow placemento Continuous belt lamination

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Pre-impregnation techniques

Hot-melt Solution

(Pseudo-Thermoplastics)

Flemming, M, Ziegmann, G., Roth, S., Faserverbundbauweisen, Halbzeuge und Bauweisen, Springer, 1996

Fiber spreading deviceNozzle

Extruder

Rewinder Conveyor belt

Roll-compactiondevice

Bobbin gate

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Post-impregnated product forms

Film stacking Cowoven fabric Powder coating Commingling yarns

(hybridisation)

D.C. Leach, Continuous Fibre Reinforced Thermoplastic Matrix Composites. In: I.K. Partridge, Ed., Advanced Composites, Chapter 2, pages 43-109. Elsevier, sci. Publl. LTD, Essex, UK, 1989.U. Thomann, Direct Stamp Forming of Non-ConsolidatedCarbon/Thermoplastic Fibre Commingled Yarns, Diss. ETH No. 15302, Zurich, 2003

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Post-impregnated product forms

G.W. Ehrenstein, Faserverbind-Kunststoffe, Hanser Verlag, München, 2006.

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Commingled yarn

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Commingled yarn

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Hybrid Yarns: Different consolidation stages

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Dry Powder impregnation

Varughese, B., Muzzy, J. and Baucom, R. M., 21st Int. SAMPE Technical Conference, 1989.

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FIT: Fibre Impregnated with Thermoplastics

Neitzel, M., Breuer, U., Die Verarbeitungstechnik der Faser-Kunststoff-Verbunde, Carl Hanser Verlag, München, 1997.

Fiber materialFluidised bed

ExtruderRewinder

Cooling

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Powder coated sheathed yarn

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Powder coated sheathed yarn

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Low

Short

Long Cycle time

High

Need for flexible, perfectly mingled materials for thermoplastic composites.

Part Complexity

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Intermediate Materials for Thermoplastic Composites

• Intermediate materials are used to bring reinforcing fibres and matrix together to reduce the distances that the high viscosity melts need to flow to achieve complete impregnation and consolidation

• Intermediate materials are avaiable where the hybridization is on the level of the laminate, the textile, the yarn, and the fibres, as well as and fully consolidated.

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Intermediate material of the future?