CO2 laser high-speed crack-free cutting of thick-section alumina based on close-piercing lapping technique

The greatest obstacles encountered in laser cutting of thick-section ceramics are catastrophic fracture and low cutting speed. Close-piercing lapping (CPL) technique has provided a cutting strategy via suppressing the thermal stress development during cutting to achieve crack-free cutting. Although this technique provided a wide operating window, the low process efficiency limited it to further industrial applications. In order to improve the process efficiency, the mechanism of CPL crack-free cutting should be understood and hence, the corresponding process parameters can be optimised for high-speed crack-free cutting. Based on the numerical and experimental study in this work, it was found that the sufficient cooling effect during laser-off periods was crucial to develop a low thermal-stress distribution during CPL cutting, by which the crack-free cutting can be achieved. Based on this finding, a low pulse repetition rate with low pulse duty cycle cutting process was proposed. Also, a procedure for process parameters optimisation was presented, by which CO2 laser high-speed crack-free profile cutting of 6 mm thick alumina was demonstrated. The corresponding cutting speed (i.e. 90 mm/min for straight line cutting and 80 mm/min for profile cutting) was significantly higher than the CPL technique (i.e. 12 mm/min).

[1]  M. Khelkhal,et al.  Determination of effective optical constants of infrared CO(2) waveguide laser materials. , 1992, Applied optics.

[2]  Chwan-Huei Tsai,et al.  Laser cutting of thick ceramic substrates by controlled fracture technique , 2003 .

[3]  S. P. Dutta,et al.  Application trend in advanced ceramic technologies , 2001 .

[4]  Lin Li,et al.  Experimental and theoretical investigation of fibre laser crack-free cutting of thick-section alumina , 2011 .

[5]  N. Dahotre,et al.  Laser machining of structural ceramics—A review , 2009 .

[6]  X. C. Wang,et al.  High quality femtosecond laser cutting of alumina substrates , 2010 .

[7]  V. Yadava,et al.  Experimental study of Nd:YAG laser beam machining—An overview , 2008 .

[8]  A. E. Segall,et al.  Faster and Damage-Reduced Laser-Cutting of Thick Ceramics Using a Simultaneous Prescore Approach , 2005 .

[9]  A. E. Segall,et al.  Controlled-fracture of prescored alumina ceramics using simultaneous CO2 lasers , 2006 .

[10]  I. Black,et al.  A laser beam machining (LBM) database for the cutting of ceramic tile , 1998 .

[11]  Mohammad Sheikh,et al.  The Effect of Laser Beam Geometry on Cut Path Deviation in Diode Laser Chip-Free Cutting of Glass , 2010 .

[12]  F. Varas,et al.  Theoretical analysis of material removal mechanisms in pulsed laser fusion cutting of ceramics , 2005 .

[13]  U. Unger,et al.  The cutting edge of laser technology , 1998 .

[14]  Mohammad Sheikh,et al.  Effect of thermal stresses on chip-free diode laser cutting of glass , 2009 .

[15]  Chwan-Huei Tsai,et al.  Formation of the breaking surface of alumina in laser cutting with a controlled fracture technique , 2003 .

[16]  P. Sánchez-soto,et al.  Laser cutting of high-vitrified ceramic materials: development of a method using a Nd:YAG laser to avoid catastrophic breakdown , 2002 .

[17]  A. Segall,et al.  Studies on the use of offset and angled prescores for fracture control during laser machining of alumina ceramics , 2006 .

[18]  Chwan-Huei Tsai,et al.  Applying an On-line Crack Detection Technique For Laser Cutting by Controlled Fracture , 2001 .

[19]  Wei Wang,et al.  CO2 laser underwater machining of deep cavities in alumina , 2011 .

[20]  V. V. Vikulin,et al.  Advanced ceramic structural materials , 2004 .

[21]  Duncan P. Hand,et al.  A Fiber‐Laser Process for Cutting Thick Yttria‐Stabilized Zirconia: Application and Modeling , 2011 .

[22]  I. Black,et al.  Laser cutting of thick ceramic tile , 1997 .

[23]  M. Modest,et al.  Temperature-Dependent Absorptances of Ceramics for Nd:YAG and CO2 Laser Processing Applications , 1998 .

[24]  Pranav Shrotriya,et al.  Thermal stress fracture mode of CO2 laser cutting of aluminum nitride , 2008 .

[25]  Graham Rutterford,et al.  Micro-machining of metals, ceramics and polymers using nanosecond lasers , 2007 .

[26]  Mohammad Sheikh,et al.  The effect of continuous and pulsed beam modes on cut path deviation in diode laser cutting of glass , 2010 .

[27]  Lin Li,et al.  Nano-second pulsed DPSS Nd:YAG laser striation-free cutting of alumina sheets , 2012 .

[28]  Mariano Perez-Amor,et al.  Single-Pass and Multi-Pass Laser Cutting of Si–SiC: Assessment of the Cut Quality and Microstructure in the Heat Affected Zone , 2007 .

[29]  B. Li,et al.  Fracture control of unsupported ceramics during laser machining using a simultaneous prescore , 2005 .

[30]  P. Sheng,et al.  Plane stress model for fracture of ceramics during laser cutting , 1995 .

[31]  G. Lu,et al.  An empirical equation for crack formation in the laser cutting of ceramic plates , 1999 .

[32]  Chwan-Huei Tsai,et al.  Fracture Mechanism of Laser Cutting With Controlled Fracture , 2003 .

[33]  Paul Mativenga,et al.  Numerical simulation of laser machining of carbon-fibre-reinforced composites , 2010 .

[34]  Lingfei Ji,et al.  Crack-free cutting of thick and dense ceramics with CO2 laser by single-pass process , 2008 .

[35]  L. Lijun,et al.  A study of laser cutting engineering ceramics , 1999 .

[36]  A. Segall,et al.  Active Stressing and the Micromanipulation of Stress-States for Delaying Fracture During Unsupported Laser Cutting , 2008 .

[37]  Duncan P. Hand,et al.  Laser Micromachining of Zirconia (Y-TZP) Ceramics in the Picosecond Regime and the Impact on Material Strength , 2011 .