Infrared Heating for Composite Materials Martin Klinecky, Heraeus Noblelight Heraeus Noblelight. All rights reserved, see last page 1 INFRARED FOR COMPOSITE MATERIALS 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 Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 2 INFRARED FOR COMPOSITE MATERIALS Agenda Motivation: heating processes at composites production Heat transfer via Infrared Radiation IR Heating Composites - Results and Discussion Application Examples Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 3 MOTIVATION 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 Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 4 MOTIVATION 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 Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 5 MOTIVATION 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 Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 6 MOTIVATION 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] Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 7 Heat transfer via INFRARED Radiation Basic principles and measurement techniques Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 8 BASIC PRINCIPLES 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 Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 9 BASIC PRINCIPLES Infrared Energy Transfer – Different Emitter Types Short Wave Short Carbon Medium Wave Medium Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 10 BASIC PRINCIPLES 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 Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 11 Heating FRP With Infrared Aproach and Results Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 12 MEASUREMENT TECHNIQUE 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) Tbottom Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 13 MEASUREMENT TECHNIQUE 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 Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 14 RESULTS AND DISCUSSION 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. relativeheating time[ A maximum power density of applied power [kW/m2] 50-60 kW/m2 is sufficient Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 15 RESULTS AND DISCUSSION 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 Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 16 RESULTS AND DISCUSSION “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 Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 18 RESULTS AND DISCUSSION 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 Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 19 RESULTS AND DISCUSSION 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 Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 20 Application examples Heraeus Infrared Process Technology Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 21 Electrical Infrared Solutions Emitters Solutions . Modules & Controls & Conveyors/Lifts Martin Klinecky | Infrared Process Technology | 22 Application: Heating Yarns Example yarns Concept study Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 23 Application: Drying of fiber sizing Pyrometer for temperature monitoring Carbon IR Modules Wavelength converter on back side Heraeus @ ITV Denkendorf Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 24 Application: Braiding pultrusion process - concept Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 25 Application: Braiding pultrusion process - Real construction Heraeus @ ITV Denkendorf Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 26 Application: Braiding pultrusion process – IR Module Impressions Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 27 Application: IR welding of pressure tanks 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- noblelight.com/en/industriesandapplications/ infraredweldingofplastics.aspx Martin Klinecky | HNG-IP | Oct 2015 Heraeus Noblelight. All rights reserved, see last page 28 Application: IR softening of multi-ply, pre-preg for forming Aircraft tooling - Softening before specified profile moulding IR features: