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Tahsin Tecelli Öpöz

Micro Machining Technology. Tahsin Tecelli Öpöz. Micro EDM High speed precision grinding Micro scratching tests Modelling and simulation of machining processes. 2/25. Outline. Research environment Micro EDM High speed precision grinding Micro s cratching tests

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Tahsin Tecelli Öpöz

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  1. Micro Machining Technology Tahsin Tecelli Öpöz • Micro EDM • High speed precision grinding • Micro scratching tests • Modelling and simulation of machining processes

  2. 2/25 Outline • Research environment • Micro EDM • High speed precision grinding • Micro scratching tests • Finite Element Modelling and Simulation • Impact of the research • Publications

  3. 3/25 Research environment Precision grinding/diamond turning Micro Electrical Discharge Machining Surface metrology Robotic polishing

  4. 4/25 Micro EDMMicro electrical discharge machining of micro holes Hole shape formation (Disclosure of technological features of micro EDM) Micro Tool Manufacturing using WEDG (Dia.<10 µm) 2 1 Surface Damage in Micro EDMed Holes 3 Etched with nitric acid Etched with nitric+chromic acid

  5. 5/25 Micro EDMDischarge pulse form and surface characteristics (a) Discharge energy 12.7 µj (b) Discharge energy 123 µj

  6. 6/25 Micro EDM Micro hole end-tip shape formation Bullet tip shape Concave tip shape Flat (rough) tip shape E= 0.78 µJ, OGP=75 V E= 223 µJ, OGP=75 V E= 33.4 µJ, OGP=80 V

  7. 7/25 Micro EDM Heat affected layer in Micro EDMed holes’ wall

  8. 8/25 Micro EDM Material removal response with machining time

  9. 9/25 Micro EDM Micro hole entrance diameter with machining time

  10. 10/25 Precision grindingHigh speed applications and micro scratching tests 2 High speed precision grinding (20k – 160k rpm) 1 • Rubbing • Ploughing • Cutting 3 4 Single grit grinding test to reveal micromechanics concept in grinding Material removal mechanism stages at micro scale grinding A single grit glued onto the wheel

  11. 11/25 Micro Scratching testsScratch form measurement and profile extraction Scratches with increasing depth of cut: An example Talysurf CCI interferometer measurement

  12. 12/25 Micro Scratching testsAbrasive grit cutting edge shape alteration during scratching: Single edge and multiple edges scratch formation

  13. 13/25 Micro Scratching testsPile-up ratio variation with depth of cut at different grit cutting edges

  14. 14/25 Micro Scratching testsMaterial removal along scratch length: Pile-up ratio

  15. 15/25 Micro Scratching testsMaterial removal along scratch length: Chip removal strength

  16. 16/25 Micro Scratching testsCutting forces, force ratio, and specific energy

  17. 17/26 Micro Scratching testsAcoustic Emission (raw signal) during scratching AE characteristic of material deformation

  18. 18/25 Modelling and SimulationFEM simulation of cutting (Abaqus/Explicit, ALE adaptive meshing, JC flow stress and Damage model, Fracture energy based damage evolution)

  19. 19/25 Modelling and SimulationFEM simulation of scratching Grit tool path 3D view during scratching 3D FEM model 1st pass 2nd pass 3rd pass Multi-pass grit simulation with 10 µm apart Stress and deformation during scratching

  20. 20/25 Modelling and SimulationFEM simulation of scratching Material deformation with friction: Longitudinal section Cross section at the end of step-2 Material deformation with friction: Lateral cross section Cross section at the end of step-3

  21. 21/25 Modelling and SimulationFEM simulation of scratching FEM scratch simulation Similar trend obtained along the scratch length Experimental scratch test

  22. 22/25 Modelling and SimulationFEM simulation of scratching Cutting forces along scratch length at different cutting speeds

  23. 23/25 Impact of the research Applications of Micro EDM • Micro EDM; • Emerging technology for micro mould manufacturing • (medical devices, surgical equipments, biomedical implants etc.) • Contacted by Rolls-Royce Plc. to be consulted on blind micro holes and micro slots Micro EDMing(used in sound reflector) Grinding; • Optimization of machining process • Designing grinding wheel • Prediction of machining quality • Optics, medical, aerospace, mould industry Nozzle for diesel injectors Plastic gear for watches Micro holes on turbine blades (http://www.sarix.com)

  24. 24/25 Publications19 publications including peer reviewed journals and conferences

  25. 25/25 Thank You...

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