Material specific Potential of Thermosets for hybrid material systems Wekstoffwoche 28.03.2017, Iserlohn Dr. Gerrit Hülder, Torsten Maenz Robert Bosch Gmbh, Corporate Research, Renningen, Germany

Agenda Introduction and motivation Hybrid materials based on magnetic fillers Heat conductive thermosets EMC shielding polymer based hybrid materials Conclusion and Outlook 2 Dr. Gerrit Hülder, Dr. Sven-Robert Raisch, Torsten Maenz | 26.09.2017 © Robert Bosch GmbH 2017. Alle Rechte vorbehalten, auch bzgl. jeder Verfügung, Verwertung, Reproduktion, Bearbeitung, Weitergabe sowie für den Fall von Schutzrechtsanmeldungen.

Introduction – why thermoset? Material specific potential of thermosets for hybrid materials Introduction – why thermoset? Shrinkage Thermal elongation Thermo-mechanics Creep 100 30 40 50 60 70 80 90 25 175 relative Steifigkeit [%] Temperatur [°C] 2,0 1,6 1,2 0,8 0,4 1 10 100 1000 Zeit [h] Dehnung [%] σ = 50 MPa T = 150 °C transverse to flow direction transverse to flow parallel to flow direction parallel to flow Thermoset Thermoplastic PF 55% GF PF 80% (GF + GB) PPA 35% GF PPS 40% GF Higher filler amount possible compared to thermoplastics Lower wall thickness possible due to lower viscosity Excellent media and temperature resistance Less thermal degradation of fillers due to lower processing temperatures 3 Dr. Gerrit Hülder, Dr. Sven-Robert Raisch, Torsten Maenz | 26.09.2017 © Robert Bosch GmbH 2017. Alle Rechte vorbehalten, auch bzgl. jeder Verfügung, Verwertung, Reproduktion, Bearbeitung, Weitergabe sowie für den Fall von Schutzrechtsanmeldungen.

Material specific potential of thermosets for hybrid materials Motivation Most mechatronic systems consist of a complex build-up of single components each only featuring one major function (e.g. housings, heat sinks, pressed-in magnets). This leads to high system costs due to large numbers of components and multiple assembly steps. Thermosets suit a number of essential requirements for mechatronic systems (e.g. media resistance, low creep, good electrical properties, low CTE1). Injection molding is a large scale production technology with only few limitations in design freedom which in terms of thermosets allows processing with very low tolerances (IT 7-9). “Customizing” the functional properties of the thermoset resins by adding functional fillers enables totally new design concepts for mechatronic components reducing process chains to a minimum. 1: Coefficient of Thermal Elongation 4 Dr. Gerrit Hülder, Dr. Sven-Robert Raisch, Torsten Maenz | 26.09.2017 © Robert Bosch GmbH 2017. Alle Rechte vorbehalten, auch bzgl. jeder Verfügung, Verwertung, Reproduktion, Bearbeitung, Weitergabe sowie für den Fall von Schutzrechtsanmeldungen.

Fundamentals – magnetic properties Material specific potential of thermosets for hybrid materials Fundamentals – magnetic properties Classification magnetic materials Magnetism Anisotropy: Caused by crystal orientation Magnetic properties vary in dependence of orientation Hyteresis curve New curve sintered NdFeB BR … Remanence HcJ, HcB … Coercivity (BH)max … Maximum energy product Magnetic flux density B Magnetic polarization J bonded compression sintered SmCo bonded NdFeB (anisotropic) SmCo IM* Remanence compression IM* bonded NdFeB (isotropic) sintered ferrite Magnetic field bonded ferrite IM*= Injection molding (thermoplastic) Coercivity Source: G.W. Ehrenstein, D.Drummer; „Kunststoffgebundene Dauermagnete – Werkstoffe, Fertigungsverfahren und Eigenschaften“, 2004, Erlangen, ISBN 3-935065-16-7, Springer VDI-Verlag 5 Dr. Gerrit Hülder, Dr. Sven-Robert Raisch, Torsten Maenz | 26.09.2017 © Robert Bosch GmbH 2017. Alle Rechte vorbehalten, auch bzgl. jeder Verfügung, Verwertung, Reproduktion, Bearbeitung, Weitergabe sowie für den Fall von Schutzrechtsanmeldungen.

Material specific potential of thermosets for hybrid materials Mold technology Megnatic field generated by coils Field is comparable for different thickness and temperatures Magnetic design of the mold leads to homogeneous field inside the cavity Variable plate thickness (1 – 4 mm), temperature up to 200°C, variable flow scenarios Conductive material Magnetic mold – homogenity of aligning field Coil (bobbin and winding) deg Aligning field Magnetic field Field orientation Cavity Non-conductive material Centre Edge Measuring position (distance from centre of cavity) 6 Dr. Gerrit Hülder, Dr. Sven-Robert Raisch, Torsten Maenz | 26.09.2017 © Robert Bosch GmbH 2017. Alle Rechte vorbehalten, auch bzgl. jeder Verfügung, Verwertung, Reproduktion, Bearbeitung, Weitergabe sowie für den Fall von Schutzrechtsanmeldungen.

Material specific potential of thermosets for hybrid materials Matrix-material: Epoxy resin-blackbox by Raschig Polyamide 12 as benchmark-material Filler: MQA-powder: Anisotropic, platelet-shaped magnetic powder BR = 1310 mT, HCJ = 1120 kA/m, (BH)max = 300 kJ/m³, d50 ≈ 100µm HDDR-power: anisotropic, cubic magnetic powder BR = 1320 mT, HCJ = 1110 kA/m, (BH)max = 300 kJ/m³, d50 ≈ 100µm Compound composition SEM-image of MQA-Powder Source: Magnequench International Bezeichnung Matrix Füllstoffgehalt Füllstoff Compoundierung EP + 65 Vol.-% MQA Epoxy 65 Vol.-% MQA-Powder IPF Dresden EP + 65 Vol.-% HDDR HDDR-Powder PA12 + 65 Vol.-% MQA Polyamide 12 LKT Erlangen PA12 + 65 Vol.-% HDDR 7 Dr. Gerrit Hülder, Dr. Sven-Robert Raisch, Torsten Maenz | 26.09.2017 © Robert Bosch GmbH 2017. Alle Rechte vorbehalten, auch bzgl. jeder Verfügung, Verwertung, Reproduktion, Bearbeitung, Weitergabe sowie für den Fall von Schutzrechtsanmeldungen.

Thermoplastic vs thermoset in dependence of plate thickness Material specific potential of thermosets for hybrid materials Thermoplastic vs thermoset in dependence of plate thickness Magnetic mold – homogenity of aligning field Remanence PA12 + 65 Vol-% HDDR Not processible Not processible Not processible Magnetic aligning field Significant effect of the filler geometry on processing and magnetic properties. Matrix material influences the initial orientation of the geometrically anisotropic filler particles. 8 Dr. Gerrit Hülder, Dr. Sven-Robert Raisch, Torsten Maenz | 26.09.2017 © Robert Bosch GmbH 2017. Alle Rechte vorbehalten, auch bzgl. jeder Verfügung, Verwertung, Reproduktion, Bearbeitung, Weitergabe sowie für den Fall von Schutzrechtsanmeldungen.

Rotor design using bonded permanent magnets Material specific potential of thermosets for hybrid materials Rotor design using bonded permanent magnets Ideal utilization of the material specific potentials by systematically adjusting the geometry to the magnetic and mechanical requirements. Conventional rotors usually consist of a large number of components and assembly steps respectively. Production of a complete rotor incl. molded drive-shaft and impeller feasible  cost saving potential Conductive material Permanent magnets Cavity Schnittansicht herkömmlicher Rotor Geometry of bonded rotor Cross-section of conventional rotor Geometrie geb. Rotor Non-conductive material 9 Dr. Gerrit Hülder, Dr. Sven-Robert Raisch, Torsten Maenz | 26.09.2017 © Robert Bosch GmbH 2017. Alle Rechte vorbehalten, auch bzgl. jeder Verfügung, Verwertung, Reproduktion, Bearbeitung, Weitergabe sowie für den Fall von Schutzrechtsanmeldungen.

Simulation based design - procedure Material specific potential of thermosets for hybrid materials Simulation based design - procedure Step 1 Simulation of the magnetic field inside the cavity Analysis of magnetic field strength and orientation at „each“ spot Step 2 Assigning the degree of orientation derived from experimental data to „each“ spot Material data derived from magnetic test mold Step 3 Segmentation of part (depending on necessary resolution) Simulation of the part on the basis of real material data Step 4 Analysis of flux at a certain distance from surface Comparison of different geometries and materials 10 Dr. Gerrit Hülder, Dr. Sven-Robert Raisch, Torsten Maenz | 26.09.2017 © Robert Bosch GmbH 2017. Alle Rechte vorbehalten, auch bzgl. jeder Verfügung, Verwertung, Reproduktion, Bearbeitung, Weitergabe sowie für den Fall von Schutzrechtsanmeldungen.

Rotor design using bonded permanent magnets Material specific potential of thermosets for hybrid materials Rotor design using bonded permanent magnets Flux density in air gap Improved flux density compared to original rotor possible Weight of laminated stack and magnets: approx. 65 g Weight of bonded rotor with improved inner geometry: approx. 36 g* Bonded rotor needs more NdFeB (approx. 33,12 g) compared to original rotor (approx. 19,58 g) * Length adjusted to magnetic flux, both calculations without drive shaft and encapsulation Flux density in air gap Flux density in air gap Flux density in air gap Measuring position By using anisotropic, polymer bonded magnets and an optimized geometry the magnetic flux can be improved and weight reduced. 11 Dr. Gerrit Hülder, Dr. Sven-Robert Raisch, Torsten Maenz | 26.09.2017 © Robert Bosch GmbH 2017. Alle Rechte vorbehalten, auch bzgl. jeder Verfügung, Verwertung, Reproduktion, Bearbeitung, Weitergabe sowie für den Fall von Schutzrechtsanmeldungen.

Flow behavior of thermoplastics and thermosets Material specific potential of thermosets for hybrid materials Flow behavior of thermoplastics and thermosets Flow behavior thermoplastics direction direction direction z x y Flow velocity Flow front [1] Heat conductivity Flow behavior thermoplastics Flow velocity Flow front z x y [2] dir dir dir dir dir dir dir dir dir dir dir dir Strong dependency of filler orientation from the wall thickness [1] F. Johannaber, W. Michaeli; „Handbuch Spritzgießen“, 2004 [2] W. Michaeli, D. Hunold, T. Kloubert; Plastverarbeiter, 12:42-46, 1992 12 Dr. Gerrit Hülder, Dr. Sven-Robert Raisch, Torsten Maenz | 26.09.2017 © Robert Bosch GmbH 2017. Alle Rechte vorbehalten, auch bzgl. jeder Verfügung, Verwertung, Reproduktion, Bearbeitung, Weitergabe sowie für den Fall von Schutzrechtsanmeldungen.

Results from power consumption measurement Material specific potential of thermosets for hybrid materials Results from power consumption measurement 100 95 90 85 80 75 70 100 95 90 85 80 75 70 Temperature [°C] Temperature [°C] 100 95 90 85 80 75 70 100 95 90 85 80 75 70 2,75 W/mK 0,98 W/mK 0,55 W/mK Heat conductivity in z-direction Temperature [°C] Temperature [°C] 100 95 90 85 80 75 70 100 95 90 85 80 75 70 Temperature [°C] Temperature [°C] 13 Dr. Gerrit Hülder, Dr. Sven-Robert Raisch, Torsten Maenz | 26.09.2017 © Robert Bosch GmbH 2017. Alle Rechte vorbehalten, auch bzgl. jeder Verfügung, Verwertung, Reproduktion, Bearbeitung, Weitergabe sowie für den Fall von Schutzrechtsanmeldungen.

Power consumption – material influence Material specific potential of thermosets for hybrid materials Power consumption – material influence Heat conductivity of different compounds Power consumption of different compounds Set temperature = 100 °C Heat conductivity Power consumption Free convection Forced convection (0,8 m/s) Forced convection (2,0 m/s) x-dir. y-dir. z-dir. x-dir. y-dir. z-dir. x-dir. y-dir. z-dir. free free free Heat conductivity and power consumption are not proportional. For higher heat conductivity the heat dissipation for forced convection increases. 14 Dr. Gerrit Hülder, Dr. Sven-Robert Raisch, Torsten Maenz | 26.09.2017 © Robert Bosch GmbH 2017. Alle Rechte vorbehalten, auch bzgl. jeder Verfügung, Verwertung, Reproduktion, Bearbeitung, Weitergabe sowie für den Fall von Schutzrechtsanmeldungen.

EMC-shielding with polymers – Challenges Material specific potential of thermosets for hybrid materials EMC-shielding with polymers – Challenges Understanding of the interaction between the material and process related influence factors : Fillers (material, shape, orientation) Filler degree Influence of processing (temperature, pressure, injection speed,…) Measurement technology: comparability of material characterization Procedure for system analysis Transferability between material characteristics on system level Connection technology: Electrical contacting between several housing parts (plastic-plastic, plastic- metal) Long-term behavior and media influence: Shielding over product life time Long-term adhesion of coatings Bonding between metal meshes and foils at back injection molding technology Simulation: Modelling of EMC characteristics (especially in the field of plastic compounds) 15 Dr. Gerrit Hülder, Dr. Sven-Robert Raisch, Torsten Maenz | 26.09.2017 © Robert Bosch GmbH 2017. Alle Rechte vorbehalten, auch bzgl. jeder Verfügung, Verwertung, Reproduktion, Bearbeitung, Weitergabe sowie für den Fall von Schutzrechtsanmeldungen.

EMC - Measurement Approach Material specific potential of thermosets for hybrid materials EMC - Measurement Approach Evaluation of material properties: Shielding attenuation measurements of selected specimen (e.g. C1, C2, C3 …) Derivation of so called “intrinsic material properties” from measured S-parameter data (ZDUT) Idea: Using ZDUT as alternative input data for modelling housings in a 3D simulation tool Transfer of material properties on assembly techniques of housings: Evaluation within EMC component testing procedures Identification of cause and effect on EMC system behavior Benefit (cost savings) vs. risks (long term behavior, aging, assembly techniques) C1 Shielding effectivness [dB] C2 C3 1 100 1000 Frequency [MHz] Limit value DUT w/o housing Electrical field strengh [dBµV/m] DUT with metalized housing, e.g. C2 DUT with metal housing 1 100 1000 Frequency [MHz] 16 Dr. Gerrit Hülder, Dr. Sven-Robert Raisch, Torsten Maenz | 26.09.2017 © Robert Bosch GmbH 2017. Alle Rechte vorbehalten, auch bzgl. jeder Verfügung, Verwertung, Reproduktion, Bearbeitung, Weitergabe sowie für den Fall von Schutzrechtsanmeldungen.

Measurement Equipment: Evaluation of Material Properties Material specific potential of thermosets for hybrid materials Measurement Equipment: Evaluation of Material Properties Requirements Close to standard (ASTM D 4935-99) High degree of reproducibility (< +/-2 dB) Broad frequency range (kHz – GHz) Adequate dynamic range (> 100 dB) Measurement data as complex numbers (S) Specimen da = 76,2 di=33 DA = 133,1 Reference DUT (Device Under Test) TEM* – Cell Measured Data 2 – port scattering parameters: S11 , S12 , S21 , S22 adB (f) = 20 * log10 | S21Ref / S21DUT | Frequency range (evaluated): 1 MHz up to 1,5 GHz Dynamic range: 130 dB 17 Dr. Gerrit Hülder, Dr. Sven-Robert Raisch, Torsten Maenz | 26.09.2017 * Transversal Electro Magnetic © Robert Bosch GmbH 2017. Alle Rechte vorbehalten, auch bzgl. jeder Verfügung, Verwertung, Reproduktion, Bearbeitung, Weitergabe sowie für den Fall von Schutzrechtsanmeldungen.

Material specific potential of thermosets for hybrid materials Measurement Results Shielding effectiveness of collected materials Measured E – Field acc. CISPR25 Monopole Limit values Fig. 1 Metal Grids Fig. 2 Conductive Compounds and Foams Fig. 1 Plastic vs. Sintered Alu Fig. 2 Copper Grid Fig. 3 Metal laminated Foils Fig. 4 Metallized Fabrics/Fleece Fig. 3 Aluminium Foil Fig. 4 Compound (CF30) 18 Dr. Gerrit Hülder, Dr. Sven-Robert Raisch, Torsten Maenz | 26.09.2017 © Robert Bosch GmbH 2017. Alle Rechte vorbehalten, auch bzgl. jeder Verfügung, Verwertung, Reproduktion, Bearbeitung, Weitergabe sowie für den Fall von Schutzrechtsanmeldungen.

Conclusion and outlook Material specific potential of thermosets for hybrid materials Conclusion and outlook Thermoset show great potential as a basis for hybrid materials Apart from functional properties the high achievable filler contents allow improved mechanical stability by using additional fillers for reinforcement. The specific thermoset flow behavior needs to be considered when designing functional parts. The specific properties of the matrix material are the key to their application. Further improvements especially in the field of characterization of the processing properties of thermoset molding compounds are necessary to achieve competitiveness of thermosets. For an effective utilization of the material specific potential in future a combination of process and part simulation (e.g. filler orientation) is necessary. 19 Dr. Gerrit Hülder, Dr. Sven-Robert Raisch, Torsten Maenz | 26.09.2017 © Robert Bosch GmbH 2017. Alle Rechte vorbehalten, auch bzgl. jeder Verfügung, Verwertung, Reproduktion, Bearbeitung, Weitergabe sowie für den Fall von Schutzrechtsanmeldungen.

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