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Andreas_Kacaras

Dipl.-Ing. Andreas Kacaras

Akad. Mitarbeiter
Bereich: Fertigungs- und Werkstofftechnik
Sprechstunden: nach Vereinbarung
Raum: 109, Geb. 10.93
Tel.: +49 721 608-44015
Fax: +49 721 608-45004
Andreas KacarasQjp5∂kit edu

 Campus Süd



Dipl.-Ing. Andreas Kacaras

Forschungs- und Arbeitsgebiete:

  • Mechanische Oberflächenbehandlung mittels Stream Finishing
  • Lasermikrostrukturierung

 

Projekte:

  • DFG-Projekt: „Fertigung optimierter technischer Oberflächen durch eine Verfahrenskombination aus Stream Finishing und Laserablation“

 

Versuchsstände:

Veröffentlichungen

[ 1 ] Hoppen, P.; Kacaras, A.; Matuschka, B. & Schulze, V. (2015), „Bearbeitung metallischer Gläser auf Fe- und Zr-Basis mittels Mikrofräsen, Mikrofunkenerosion und Mikrolaserabtragen“. 7. Kolloquium Mikroproduktion, Hrsg. Institut für Kunststoffverarbeitung, S. 1-7.
Abstract:
Die Bearbeitung metallischer Gläser auf Zr- und Fe-Basis zur Herstellung technischer Oberflächen stellt die Fertigung vor zwei Herausforderungen: die Entwicklung eines stabilen Prozesses, um die benötigte Oberflächenqualität zu erzeugen und die Vermeidung von Kristallisation, um die Eigenschaften metallischer Gläser nicht zu verändern. Dabei hat sich gezeigt, dass die Bearbeitung von Proben auf Zr-Basis zu guten Ergebnissen führt, während dies bei Proben auf Fe-Basis nur unter bestimmten Randbedingungen möglich ist.

[ 2 ] Schulze, V.; Gibmeier, J. & Kacaras, A. (2017), „Qualification of the stream finishing process for surface modification“, CIRP Annals - Manufacturing Technology, S. 523-526. http://dx.doi.org/10.1016/j.cirp.2017.04.079
Abstract:
The stream finishing process represents an established and efficient production process for surface smoothing and edge rounding. In addition to the targeted setting of a defined surface topography the process features a high potential for mechanical surface modification that has not been realized yet. In this work the stream finishing process is carried out on normalised AISI4140 plane specimen with the aim of efficiently determining optimal processing time for surface modification (micro hardness, residual stresses, surface topography). In this context, the suitability of the Almen system [1] as an efficient method for characterizing change in residual stress during stream finishing is investigated.

[ 3 ] Zanger, F.; Kacaras, A.; Bächle, M.; Schwabe, M.; Puente Léon, F. & Schulze, V. (2018), „FEM simulation and acoustic emission based characterization of chip segmentation frequency in machining of Ti-6Al-4V“. 51st CIRP Conference on Manufacturing Systems, Hrsg. Procedia CIRP, S. 1421-1426.
Abstract:
FEM chip formation simulations and machining tests of orthogonal cutting were undertaken in order to investigate the influence of cutting speed and tool wear on cutting force, chip segmentation frequency, and residual stress state for Ti-6Al-4V. In addition, acoustic emissions, measured by a piezoelectric sensor adapted to the tool shank, were analyzed to extract chip segmentation frequency in-process using time-frequency representations and periodograms. Results show the capability of robust chip segmentation frequency measuring. The hypothesis of compensating the negative effect of tool wear on the component’s residual stress state by means of targeted adjustment of process parameters can be derived.

[ 4 ] Kacaras, A.; Gibmeier, J.; Zanger, F. & Schulze, V. (2018), „Influence of rotational speed on surface states after stream finishing“. 4th CIRP Conference on Surface Integrity, Hrsg. Procedia CIRP, S. 221-226.
Abstract:
The stream finishing process proved to be an efficient production process for mechanical surface modification. In particular the rotational speed of a bowl containing the media represents an effective process variable for increasing relative velocity between workpiece and media. Increased work hardening effects and induced compressive residual stresses in the near surface region are expected. In this work the temporal influence of the rotational speed of the bowl on work hardening, residual stresses and surface topography are investigated on quenched and tempered AISI4140 plane specimen with the aim of determining the optimal processing time for surface modification. Furthermore, it is investigated whether grain refinement occurs during stream finishing. A modified Almen system is used as an efficient method for characterizing changes in residual stresses and surface topography during stream finishing. While depth ranges of residual stresses and work hardening showed to be affected by the rotational speed of the bowl and the processing time during stream finishing, residual stress states at the surface showed to be invariant. Increased process efficiency can be obtained by stream finishing using high rotational speed yielding higher depths of induced compressive residual stresses and work hardening in the near surface region in a shorter processing time.