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DFG CRC/Transregio 39 PT-PIESA
SP A02

Mikrostrukturierung und automatisierte Fügetechnologien für Piezofasern in metallische Trägerwerkstoffe

A. Schubert, H.-J. Koriath
  1. Aims
  2. Results
  3. Methods
  4. Publications
  5. Contact


Increase of productivity and process reliability of microstructuring and joining processes for integration piezo fiber batches in metallic structures suitable for mass production process chains

  • hybrid forming and joining processes with elastic tolerance compensation
  • increase of process reliability and reproduction by using inherent sensor functionality of the piezo fibre batch for intelligent process control of the joining process
  • process development of sealing technologies of the active zone to protect against media, mechanical damages and electrical insulation



Microstructuring by micro forming

Micro impact extrusion
  • Expansion to secondary structures
  • Reduction of the distance- and width tolerances by 75% compared to project phase 1
  • Aspect Ratio  > 1
  • Reduction of forming force by 47% (including secondary structures)
Hybrid Microforming
  • Shear displacement forming of planar secondary structures
  • Combination of micro impact extrusion and shear displacement forming in one press stroke →  hybrid microforming
  • Force reduction by 22% compared to impact extrusion

Micrograph a) Mmicro impact extrusion, b) hybrid forming,
 red Line = initial sheet thickness

Process input variables

Investigation of:
  • stamp velocity, pressing force
  • Tool coatings, tool materials, tool configurations
  • Sheet thickness and alloys
  • Lubrication conditions
  • Umformprozesse
  • Variation of structure size
cavity depth in dependency on forming force and tool coating

Joining technologies

Joining of PSV
  • Joining by forming through upsetting of the cavity webs
  • through form- and  interference-fit joined interconnected piezo ceramic fibres
  • optimizing of the geometry for joining by forming without fibre cracks
Deep drawing
  • deep drawing process after joining by forming
  • punch radii R=100 mm; 250 mm
  • no recognizable fibre cracks

Fertigung und Montage von Piezo-Sprossen-Verbunden (PSV)

a02 a02
Automatisierte Mikromontage
  • Lagemessung mit Bildverarbeitung: Wiederholgenauigkeit: 1,2 µm
  • Positionsunsicherheit (gesamt): 5,1 µm
  • konfokale Messung der Kavitätstiefe
  • Montage mit ±6,5 µm Fügespalt
→ Fügespaltreduzierung um 43%

Integrierte Piezo-Sprossen-Verbunde für die Strukturüberwachung (SHM)



Hybrid forming technologies
  • warm forming
  • vibration assisted forming
  • sealing of the active zone
  • Design of Experiments for optimization of the technology parameters
flow curves of EN-AW 5182
(according to Ostermann)
Elastic tolerance compensation
  • costumized forming force per web and piezo fibre
  • reduced tolerance requirements on PSV (A03) and sheet metal
sketch of elastic tolerance compensation        
Process control with PSV as sensor
  • contacting of the PSV during joining by forming
  • Qualifying of measurement signals
  • Process control of the interference-fit between PSV-sheet
 sketch of contacting during joining           
Charakterisierung von Eigenschaften
  • Forming: sections, roughness measure-ments, 2D/3D-microscopy, SEM
  • Module properties: frequency response, linearity, electrical insulation






section of joined piezo ceramicelements

Functional test and quality assurance
  • Test of module functionality by static / dynamic excitation
  • Evaluation of process capability
  • Failure mode and effects analysis
Kraft-Auslenkung-Kennfeld des Piezo-Metall-Verbunds


Reviewed Publications

[Dro13] Drossel W-G, Hensel S, Nestler M, Lachmann L, Schubert A, Müller M, Müller B (2014)
Experimental and numerical study on shaping of aluminum sheets with integrated piezoceramic fibers. J Mater Process Technol 214(2):217-228
[Sch13a] Schubert A, Wittstock V, Jahn SF, Müller B, Müller M (2013)
Joining by forming of piezoceramic macro-fiber arrays within micro-structured surfaces of aluminum sheets. Prod Eng, doi:10.1007/s11740-013-0498-7
[Sch13b] Schubert A, Wittstock V, Koriath H-J, Jahn SF, Peter S, Müller B, Müller M (2013)
Smart Metal Sheets by Direct Functional Integration of Piezoceramic Fibers. Microsys Technol, doi:10.1007/s00542-013-1836-6
[Sch13c] Schubert A, Jahn SF, Müller B (2013)
Microstructuring by a Combination of Micro Impact Extrusion and Shear Displacement Forming. Key Eng Mater 554-557:893-899
[Neu13a] Neugebauer R, Koriath H-J, Müller M (2013)
Assembly of smart adaptronic piezo-metal composites by use of prefabricated batches of piezoceramic micro part. In: Proc. SPIE 8692, 869224
[Sch14] Schubert A, Jahn SF, Müller B (2014)
Modular Tool Concept and Process Design for Micro Impact Extrusion. Prec Eng 38(1):57-63

Other publications

[Neu13b] Neugebauer R, Schubert A, Koriath H-J, Jahn SF, Müller B, Müller M (2013)
Microfabricated piezo- metal substructures for sensor integration in large sheet metal parts. In: Proc 13th euspen, vol 2, pp 109-112
[Sch13d] Schubert A, Neugebauer R, Jahn SF, Müller M, Müller B (2013)
Integration von Piezosensorik in Aluminiumbleche für das Structural Health Monitoring. In: 19. Symp Verbundwerkst Werkstoffverb, S 664-672
[Sch12a] Schubert A, Jahn SF, Müller B (2012)
Umformende Mikrostrukturierung von Blechwerkstoffen für die Herstellung von Piezo-Metall-Modulen. In: Proc 4th ICAFT. Chemnitz, Germany, S 411-424
[Sch12b] Schubert A, Jahn SF, Müller B (2012)
Influence of Different Tool Materials, Coatings and Lubricants onto Shape Accuracy during Micro Impact Extrusion. In: Proc 12th euspen, vol 2, pp 75-79
[Neu11a] Neugebauer R, Koriath H-J, Regel J, Müller M (2011)
Process chain and tolerance management for precision manufacturing of piezo-metal-modules. In: Proc ISEM, pp 54(1)-54(12)
[Neu11b] Neugebauer R, Koriath H-J, Richter M, Müller M (2011)
Miniature 3-DOF planar parallel kinematics with large work space for precision positioning of endeffectors. In: Proc 11th euspen, vol 2, pp 315-318


Project Manager:

Prof.Dr.-Ing. Andreas Schubert
Technische Universität Chemnitz
Fakultät für Maschinenwesen
Professur für Mikrofertigungstechnik (MFT)
09107 Chemnitz

Phone: +49 371 531-34580


Dr.-Ing. Hans-Joachim Koriath
Fraunhofer-Institut für Werkzeugmaschinen und Umformtechnik IWU
Reichenhainer Str. 88
09126 Chemnitz

Phone: +49 371 5397-1485


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