Infrared Heating for Composite Materials

Martin Klinecky, Heraeus Noblelight

Introduction

Martin Klinecky - Heraeus Noblelight Germany

. Electrical engineer, graduate 1999 / Germany

. Area Sales Manager – Infrared Process Technology

. Responsible for eastern Europe, Scandinavia, Brazil

. With Heraeus Noblelight since 2001

. until 2014 R&D of Infrared Emitters

Agenda

Motivation: heating processes at composites production

Heat transfer via Infrared Radiation

IR Heating Composites - Results and Discussion

Application Examples

Heating processes during composites production

Fiber pretreatment . Applying and drying of fiber sizing . Surface activating

Processing of thermoplastic FRP Processing of thermoset FRP . Before or during compounding . Start polymerization . Infiltration . Decrease temperature difference . Pressing fiber – resin . (Re-) shaping of organo sheets: .  Save time in autoclave thermoforming process . Composite repair: bring in energy . Composite repair: bring in energy locally locally

The heating process

Conventional oven . Energy transfer via medium – detour of energy . Low efficiency due to low heat conductivity and low thermal heat transfer coefficient . Air is good for complex structures but very slow

Conventional …heats … heats air oven workpiece

…heats Infrared workpiece directly Processing time

The heating process

Infrared . Energy transfer directly to workpiece . High efficiency for most polymer matrices (high absorptions) . Fast, controllable and adjustable system: heat on demand

Conventional …heats … heats air oven workpiece

…heats Infrared workpiece directly Processing time

INFRARED vs Convection

App. 50% energy savings kW/m2 App. 80% space saving Infrared Heat up to 1 MW/m2 Process time reduction 80 Clean / dust-free working Source: RWE 1991 60 INFRARED further features

Precise process control 40 Contact-free, no contamination V = 10m/s No enclosure needed 20 Convection Heat Industry experienced equipment up to 40 kW/m2 V = 1m/s 0 200 400 600 T [°C]

Basic principles and measurement techniques

Infrared Energy Transfer

Thermal radiation is energy… . …emitted by hot matter . …transported by radiation

Energy transfer without a medium

Spectral distribution depends on source temperature (Planck´s law) . Industrial heating processes work best in spectral range between 1-5 µm due to high power densities . Heraeus emitters cover full relevant range for IR applications

Infrared Energy Transfer – Different Emitter Types

Short Wave Short

Carbon

Medium Wave Medium

Infrared Energy Transfer – Risks and Safety Precautions

Hot surfaces contact

. Cover, fence

Eye stress Short Wave Short . Cover, glasses Skin stress

. Distance, cover

Material overheating Carbon . power regulation . temperature monitoring European Regulations: . DIN EN12198

. DIN EN 14255 Medium Wave Medium

Aproach and Results

Testing of IR Heating for Composites - Approach

Samples were irradiated from one side (top) Ttop Temperature was monitored on thickness FRP irradiated side and non-irradiated side (bottom) T bottom

Testing of IR Heating for Composites - Approach

Samples were irradiated from one side (top) Ttop Temperature was monitored on thickness FRP irradiated side and non-irradiated side (bottom) T bottom When Temperature on irradiated surface is reached (heating time), Remove sample sample was removed from emitter T top field Temperature difference between top

T-gradient and bottom ( T-Gradient) Start Tbottom Time-Temperature-curves were Heating time created

Influence of Spectrum and Power: Heating Time

IR-heating of C/PPS, 4.3mm The higher power, the shorter heating time for CFRP material

Carbon (MW) ] - Short-wave

No difference between medium- wave carbon emitter and short- wave emitter in heating time on

top surface is observed. relativeheatingtime[

A maximum power density of applied power [kW/m2] 50-60 kW/m2 is sufficient

Influence of Spectrum and Power: Temperature Gradient

IR-heating of C/PPS, 4.3 mm Temperature gradient increases Carbon (MW)

/mm] with higher power density ° Short-wave short-wave emitters show a distinct smaller temperature gradient than medium-wave carbon emitters ! . Deeper penetration depth of short- wave radiation.

Temperature gradient [ Temperature .  good for samples with high thickness applied power [kW/m2] . decrease of thermal stresses in material  gentle heat process

“Good absorption” or “volume heating (deep penetration)”?

medium-wave emitter short-wave emitter • Absorption (Lambert-Beer) • IR excitation on surface: • Inelastic scattering •  long ways for thermal conductivity • IR excitation in volume •  short ways for thermal conductivity Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 17 Influence of material: organo sheets Different fiber/matrix combinations  different heating times

GF/PA6

Different fibers

Different matrices GF/PPS

CF/PPS Seite 18

Influence of Material: weaves

GF/PET and CF/PET weave

CF/PET . Heating of Carbon fiber weave is GF/PET faster

. No Temperature gradient for glass fiber weave .  homogeneous heating with IR .  gradient free

Preheating of weaves before consolidation works excellent with IR-heating IR Spectrum should be considered

A good and efficient process depends on numerous factors

Power and spectra of IR system Properties of substrate . Optical properties . Thermophysical properties (heat capacity, heat conductivity, …) . Geometry (thickness, surface to volume ratio,…) Environmental conditions . Humidity . Temperature . Air flows . Reflecting walls, … An Infrared system with fast reaction times is essential for good process control. . Reaction time of Heraeus emitter: 1-2 s . Closed-loop control possible

Heraeus Infrared Process Technology

Emitters Solutions

. Modules & Controls & Conveyors/Lifts

Martin Klinecky | Infrared Process Technology | 22 Application: Heating Yarns

Example yarns Concept study

Carbon IR Modules

Wavelength converter on back side

Heraeus @ ITV Denkendorf

Polypropylene cylinder body glass-filled IR features: . efficient melting in 40s . Power focused on target surfaces . 2s reaction time, power during heating cycles only . contact free – no frequent tool cleaning Short wave emitters (19kW)

Video: http://www.heraeus-

Application: IR softening of multi-ply, pre-preg for forming

Aircraft tooling - Softening before specified profile moulding IR features: . Smaller dimensions compared to hot air oven . Not risk of contamination compared to oil-heated tools . Accurate material temperature of 70°C . Integration into robot system

De-bulking of composite layers - rear spar assembly for Airbus 350 XWB IR features: . Prevents subsequent wrinkling safe & fast . Integrated into semi robotic work stations . Tailor made and optimized IR-System Total IR power 465kW . 3 heating sections with 7 control zones each

Application: IR interim processing of laid-up composites

31 Application: IR on Composite Sheets for Foam-Sandwich Structures

Thermo-pressing of composite top and bottom layers with foam core in between IR Flexibility in Timing, Power, Geometry . Can follow different material specifications . Easy to adapt to changing semi-product sizes and geometries . Easy to transfer to series production

Thank you for your attention!

Internet: www.heraeus-noblelight.com

Email: [email protected]

Last presentation slide containing legal notices

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All data in this presentation were thoroughly ascertained by Heraeus. However, Heraeus does not assume any liability for their correctness or completeness. The data are based on conditions of use and environmental influences assumed by Heraeus. They cannot be adopted indiscriminately, but require prior verification for the respective use of the customer.

Exclusively Heraeus’ General Terms of Delivery shall apply to all deliveries of Heraeus for commercial transactions with business enterprises.

Martin Klinecky | HNG-IP | Oct 2015 Last page 34 BUSINESS GROUP SPECIALTY LIGHT SOURCES – HERAEUS NOBLELIGHT Applications

Glass Metal Plastic

Paper/Printing Food Automotive Industry

Individual IR - 3D shaped contour emitters

Plastic Material:

Thermoforming Deburring . ABS, EPDM, PC, PE, PP, PS Welding . ABS, EPDM, PA, PC, PE, POM, PP, PS, PUR, PVC

Any changes reserved, see last page of this presentation/ Änderungen vorbehalten, siehe letzte Seite dieser Präsentation 36 INFRARED APPLICATION EXAMPLES - AUTOMOTIVE

Welding of plastic dashboards for automotives

2D and 3D emitters target heat

Any changes reserved, see last page of this presentation/ Änderungen vorbehalten, siehe letzte Seite dieser 2DPräsentation and 3D emitters target heat 37 BUSINESS GROUP SPECIALTY LIGHT SOURCES – HERAEUS NOBLELIGHT ANWENDUNGEN FÜR KUNSTSTOFFE APPLICATIONS IN PLASTICS PROCESSING

 Trocknung Kleber an Glasfaser verstärkten Kunststoffstreben

 Curing glue on glassfiber reinforced plastic strutt section

Page 38 INFRARED APPLICATION EXAMPLES - AUTOMOTIVE

Pre-aging of car hoods

Any changes reserved, see last page of this presentation/ Änderungen vorbehalten, siehe letzte Seite dieser Präsentation 39 INFRARED APPLICATION EXAMPLES - AUTOMOTIVE

Leather smoothening in car seats

Any changes reserved, see last page of this presentation/ Änderungen vorbehalten, siehe letzte Seite dieser Präsentation 40 INFRARED APPLICATION EXAMPLES - AUTOMOTIVE

Adhesing of rear spoiler and rear boot badges

Any changes reserved, see last page of this presentation/ Änderungen vorbehalten, siehe letzte Seite dieser Präsentation 41 INFRARED APPLICATION EXAMPLES - AUTOMOTIVE

Hot riveting of plastic pins for automotive interior parts

Any changes reserved, see last page of this presentation/ Änderungen vorbehalten, siehe letzte Seite dieser Präsentation 42

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