Title: A study on laser-fibre coupling efficiency and ablation rate in femtosecond laser deep microdrilling

Authors: Xinwei Shen; Qiumei Bian; Zenghu Chang; Shuting Lei; Benxin Wu

Addresses: Industrial and Manufacturing Systems Engineering, Kansas State University, 2037 Durland Hall, Manhattan, KS 66506, USA. ' Industrial and Manufacturing Systems Engineering, Kansas State University, 2037 Durland Hall, Manhattan, KS 66506, USA. ' Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, KS 66506, USA. ' Industrial and Manufacturing Systems Engineering, Kansas State University, 2012 Durland Hall, Manhattan, KS 66506, USA. ' Mechanical Engineering, Illinois Institute of Technology, 243 Engineering 1 Building, Chicago, IL 60616, USA

Abstract: Laser microdrilling is a common micromachining operation in many industrial applications. This paper presents a new laser microdrilling technique in which a hollow-core fibre is employed to transmit femtosecond laser pulses to the target position. The coupling efficiency between the laser and the fibre is investigated and found to be strongly related to pulse energy and pulse duration. A parametric study on the ablation rate indicates that in microdrilling of a stainless steel (type 303), the operating parameters including pulse energy, pulse duration, sample thickness, focal length and sample-fibre distance can affect the ablation rate. The experimental results show that the new technique developed in this study is feasible to conduct microdrilling of holes with high aspect ratio.

Keywords: femtosecond laser pulses; laser microdrilling; ablation rate; hollow-core fibres; stainless steel; laser-fibre coupling; deep microdrilling; micromachining; hole drilling.

DOI: 10.1504/IJMMS.2012.048232

International Journal of Mechatronics and Manufacturing Systems, 2012 Vol.5 No.3/4, pp.280 - 293

Received: 19 Mar 2011
Accepted: 20 Oct 2011
Published online: 21 Aug 2014 *

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