Twin gas jet-assisted laser drilling through thermal barrier-coated nickel alloy substrates


SEZER H. K. , Li L., Leigh S.

INTERNATIONAL JOURNAL OF MACHINE TOOLS & MANUFACTURE, cilt.49, ss.1126-1135, 2009 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 49 Konu: 14
  • Basım Tarihi: 2009
  • Doi Numarası: 10.1016/j.ijmachtools.2009.07.002
  • Dergi Adı: INTERNATIONAL JOURNAL OF MACHINE TOOLS & MANUFACTURE
  • Sayfa Sayıları: ss.1126-1135

Özet

Laser fabrication of cooling holes in certain parts of the aero-engine components involves percussion or trepan drilling at acute angles to the surface. These parts are often covered with plasma sprayed ceramic thermal barrier coatings (TBC) to protect them from reaching excessive temperatures in hot engine environments. Delamination of the TBC is the main problem of laser drilling acute angled holes in the coated components. The present study investigates a novel technique enabling to drill through thermal barrier-coated materials without delamination. The technique is based on the control of the melt flow trajectories and impact angle on the hole walls utilizing a secondary gas jet. Delamination-free laser-drilled holes inclined at 30 to the workpiece surface have been demonstrated. Finite volume-based numerical modelling of melt flow during the drilling process was developed to understand the effect of secondary jet in the prevention of delamination. (C) 2009 Elsevier Ltd. All rights reserved.