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DFG CRC/Transregio 39 PT-PIESA
SP A06

Production technologies of piezo-modules with integrated ceramic composites and functional polymers for application in active metallic components

L. Kroll, J. Tröltzsch
  1. Objectives
  2. Results
  3. Methods
  4. Publications
  5. Contact


Production of µIMP-modules with adjusted preload of the piezo-ceramic as well as material immanent electromechanical functions based on thermoplastic piezo-ceramic composites for integration in metallic (A03) and plastic-based lightweight structures (T02) in large-scale production

  • Fully automated fabrication of discrete µIM-piezo modules
  • Variation of the material for thermoplastic piezo-ceramic composites for a robust processing by micro injection molding
  • Specifically adjustment of process-related internal compressive stresses for optimal electromechanical properties in the µIMP
  • Material modification for optimized polarization



Morphology of CNTs in micro injection molded test samples of PEEK

  • Orientation of the CNTs due to process-related near-surface shear zone
    → Directionality of electrical conductivity
  • Homogeneous distribution of CNTs with distinct network structure and without development of agglomerates
    Percolation threshold at small percentages of CNTs
  • Very high proportion of CNTs at the surface of the micro injection molded test samples
    Small electrical contact resistance
    → Slightly pronounced parasitic capacity

a) SEM micrograph of the surface of injection molded samples of PEEK
b) TEM micrograph of a partial cross-section perpendicular to the flow direction of the melt

Investigation of process-related electrical conductivities at PEEK-CNT- nanocomposite structures

  • High conductivity due to short filling process time
    → Optimal injection velocity at 550 mm/s
  • Large proportion of CNTs at the structural surface with increasing mold temperature
    Formation of the shear zone close to cavity
  • Sufficient electrical conductivity already at 7 wt.% CNT for forwarding of small signals
    Processability of nanocomposites by injection molding technologies

Electrical conductivity of PEEK filled with 7 wt.% CNT at different process parameters of injection molding

Micro injection molding process evaluation with µIMP-tool

  • Newly gripper-concept with highly tempered mounting for micro structured piezo-ceramics
    TPZT = 180°C at mold transfer with ± 5 µm positional tolerance
  • Proof of low internal stress µIMP in compact constructions
  • Defined internal compressive stresses in PZT (10 to 30 MPa) by specific adjustment of the process parameters
    Convenient electromechanical performance


a) µIMP micro injection molding tool; b) µIMP embedded in aluminum



Tool and process simulation

  • FEM-calculation of process-related internal compressive stresses
  • Analysis of form filling simulations of highly viscous melts
Thermo mechanical deformation analysis
(Scaling factor: 10; red: max. 0.5 mm; green: 0.3 mm
Production studies, sensitivity analysis
  • Characterization of production-induced material properties
  • Optimization of electromechanical performance by genetic algorithms
Young’s modulus of PEEK filled with 7 wt.% CNT as a function of tool temperature and injection rate
  • Investigation of physical and chemical surface activations to improve adhesion
  • Variation of material and geometry for adhesive bonded, positive interlocked and frictional connected composite modules
Surface activation of micro structured PZT in plasma atmosphere


Reviewed Publications

[Gra16] Graf A, Kräusel V, Landgrebe D, Decker R, Kroll L (2016)
Joining and forming of hybrid assembled composites with sensory function. Euro Hybrid Materials and Structures 2016. ISSN: 978-3-88355-414-3
[Dec15] Decker R, Heinrich M, Tröltzsch J, Kroll L (2015)
Fertigungstechnologien für Piezomodule mit integrierten Keramikkompositen und Funktionspolymeren zum Einsatz in aktiven metallischen Bauteilen. Forum Spritzgießen: Funktionsintegration - Innovationen im Kunststoffbauteil, 2015.
[Dec15] Decker R, Heinrich M, Tröltzsch J, Rhein S, Gebhardt S, Michaelis A, Kroll L (2015)
Development and characterization of piezo-active polypropylene compounds filled with PZT and CNT
In: Proceedings 5th Scientific Symposium CRC/Transregio 39, pp. 59-64, 2015.
[Fis13] Fischer T, Wetzold N, Kroll L, Hübler AC (2013)
Flexographic Printed Carbon Nanotubes on Polycarbonate Films - Yielding High Heating Rates. J Appl Polym Sci 1:1-9
[Hei15] Heinrich M, Decker R, Schaufuß J, Tröltzsch J, Mehner J, Kroll L (2015)
Electrical contact properties of micro-injection molded Polypropylene/CNT/CB-composites on metallic electrodes
In: Advanced Material Research, 1103: pp. 77-83, 2015. DOI: http://www.scientific.net/AMR.1103.77

Heinrich M, Sichting F, Kroll L (2012)
Microinjection Molding of Polypropylene (PP) Filled with MWCNT: Influence of Processing Parameters on the Mechanical Properties.
In: Proc IEEE Nanotechnol Mater Dev Conf. Honolulu, USA

[Krä15] Kräusel V, Graf A, Heinrich M, Decker R, Caspar M, Kroll L, Hardt W, Göschel A (2015)
Development of hybrid assembled composites with sensory function
In: CIRP Annals - Manufacturing Technology, 64(1), 2015. DOI: 10.1016/j.cirp.2015.04.054
[Kro11] Kroll L, Nendel W, Heinrich M, Stelzer R, Tröltzsch J, Walther M (2011)
Bewertung prozessbedingter Eigenspannungen von mikrospritzgießverarbeiteten piezoaktiven Hybridmodulen. J Plast Technol 1:17-43
[Nie13] Niedziela D, Tröltzsch J, Latz A, Kroll L (2013)
On the numerical simulation of injection molding processes with integrated textile fiber reinforcements. J Thermoplast Compos Mater 26(1):74-90
[Sch13] Schulze R, Heinrich M, Nossol P, Forke R, Sborikas M, Tsapkolenko A, Billep D, Wegener M, Kroll L, Gessner T (2013)
Piezoelectric P(VDF-TrFE) transducers assembled with micro injection molded polymers. Sens Actuators A: Phys, doi:10.1016/j.sna.2013.12.032
[Trö10] Tröltzsch J, Kroll L (2010)
Investigation of polymer melt impregnated fibre tapes in injection moulding process. In: Integr Syst Des Technol. Springer, Berlin, pp 67-78
[Ulk13] Ulke-Winter L, Klärner M, Kroll L (2013)
Determining the damping behavior of fiber reinforced composites - A new approach to find mathematical relationships in data sets. Compos Struct 100:34-39
[Wal10] Walther M, Nendel W, Heinrich M, Klärner M, Tröltzsch J, Kroll L (2010)
Initial stress behaviour of micro injection-moulded devices with integrated piezo-fibre composites. In: Integr Syst Des Technol. Springer, Berlin, pp 109-120

Andere Veröffentlichungen

[Kro13] Kroll L, Heinrich M, Nendel W (2013)
Electrical and mechanical behavior of PEEK nano composites based on carbon nano tubes. In: Proc CRC/Transregio 39. Nuremberg, Germany, pp 49-52
[Mül13] Müller M, Peter S, Berg S, Heinrich M, Walther M, Hohlfeld K, Heberle J, Quentin U, Koriath H-J, Gebhardt S, Schmidt M, Michaelis A, Kroll L, Richter F, Neugebauer R (2013)
Microstructured Piezoceramic and Fibre Composite Transducers for Active Semi-Finished Products. In: Proc CRC/Transregio 39. Nuremberg, Germany, pp 25-31
[Hei12b] Heinrich M, Kroll L, Sichting F (2012)
Process-related mechanical properties of conductive Nanocomposites based on CNT-filled Polypropylen. In: Proc NanoSpain Conf. Santander, Spain


[Fra11] Fraunhofer Gesellschaft zur Förderung der angewandten Forschung e.V. Piezoelektrisches Funktionsmodul und Verfahren zur Herstellung. Patentanmeldung WO002011038703A1. 2011-04-07
[Tec09] [Tec09] Technische Universität Chemnitz. Sensormodul, Verfahren zum Herstellen eines Sensormoduls sowie Signalerfassungs- und Verarbeitungsverfahren. Offenlegungsschrift DE102007056409A1. 2009-05-28


Project Manager:

Univ.-Prof. Dr.-Ing. habil. Lothar Kroll
Chemnitz University of Technology
Institut für Allgemeinen Maschinenbau und Kunststofftechnik
Professur Strukturleichtbau und Kunststoffverarbeitung
09107 Chemnitz

Phone: +49 371 531-38081


Dr.-Ing. Jürgen Tröltzsch
Chemnitz University of Technology
Institut für Allgemeinen Maschinenbau und Kunststofftechnik
Professur Strukturleichtbau und Kunststoffverarbeitung
09107 Chemnitz

Phone: +49 371 531-35665


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