High-throughput machining using high average power ultrashort pulse lasers and ultrafast polygon scanner

In this paper, high-throughput ultrashort pulse laser machining is investigated on various industrial grade metals (Aluminium, Copper, Stainless steel) and Al2O3 ceramic at unprecedented processing speeds. This is achieved by using a high pulse repetition frequency picosecond laser with maximum average output power of 270 W in conjunction with a unique, in-house developed two-axis polygon scanner. Initially, different concepts of polygon scanners are engineered and tested to find out the optimal architecture for ultrafast and precision laser beam scanning. Remarkable 1,000 m/s scan speed is achieved on the substrate, and thanks to the resulting low pulse overlap, thermal accumulation and plasma absorption effects are avoided at up to 20 MHz pulse repetition frequencies. In order to identify optimum processing conditions for efficient high-average power laser machining, the depths of cavities produced under varied parameter settings are analyzed and, from the results obtained, the characteristic removal values are specified. The maximum removal rate is achieved as high as 27.8 mm3/min for Aluminium, 21.4 mm3/min for Copper, 15.3 mm3/min for Stainless steel and 129.1 mm3/min for Al2O3 when full available laser power is irradiated at optimum pulse repetition frequency.

[1]  Patricia Scully,et al.  Micro processing of metals using a high repetition rate femto second laser: from laser process parameter study to machining examples , 2011 .

[2]  Tino Eidam,et al.  Femtosecond fiber CPA system emitting 830 W average output power. , 2010, Optics letters.

[3]  B. Neuenschwandera,et al.  High throughput ps-laser micro machining with a synchronized polygon line scanner , 2014 .

[4]  Robby Ebert,et al.  High rate laser micro processing using high brilli ant cw laser radiation , 2010 .

[5]  Johannes Heberle,et al.  Electro-optic and acousto-optic laser beam scanners , 2016, SPIE LASE.

[6]  Udo Loeschner,et al.  Process optimization in high-average-power ultrashort pulse laser microfabrication: how laser process parameters influence efficiency, throughput and quality , 2015 .

[7]  S. Zeng,et al.  Femtosecond pulse laser scanning using Acousto-Optic Deflector , 2009 .

[8]  Razvan Stoian,et al.  Single and multiple ultrashort laser pulse ablation threshold of Al2O3 (corundum) at different etch phases , 2000 .

[9]  Johannes Finger,et al.  High power ultra-short pulse laser ablation of IN718 using high repetition rates , 2015 .

[10]  M. Gedvilas,et al.  Use of High Repetition Rate and High Power Lasers in Microfabrication: How to Keep the Efficiency High? , 2009 .

[11]  R. D. Loor.  Polygon Scanner System for Ultra Short Pulsed Laser Micro-Machining Applications☆ , 2013 .

[12]  Stephan Brüning,et al.  High-power picosecond laser with 400W average power for large scale applications , 2012, Other Conferences.

[13]  H. Hoffmann,et al.  Compact diode-pumped 1.1 kW Yb:YAG Innoslab femtosecond amplifier. , 2010, Optics letters.

[14]  Klaus Dickmann,et al.  Micromachining using high‐power picosecond lasers , 2011 .

[15]  Joerge Schille,et al.  Investigation of micromachining using a high repetition rate femtosecond fibre laser , 2013 .

[16]  Guido Hennig,et al.  Ultrafast Scan Techniques for 3D-μm Structuring of Metal Surfaces with high repetitive ps-laser pulses , 2011 .