Improving cutting quality by analysis of microstructure characteristics and solidification behaviour of recast layer formation on laser cut ceramic

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• 作者：Xiaochuan Chen ; Lingfei Ji ; ^{ncltji@bjut.edu.cn} ; Yong Bao ; Yijian Jiang
• 关键词：Laser cutting ; Grain size ; Al2O3 ; Thermal conductivity ; Substrates
• 刊名：Journal of the European Ceramic Society
• 出版年：2012
• 期刊代码：53_09552219
• 类别：ms
• 出版时间：August, 2012
• 卷：32
• 期：10
• 页码：2203-2211
• 文件大小：1584 K

摘要

We studied the microstructure characteristics and solidification behaviour of the recast layer on a 1 mm Al₂O₃ electronic ceramic substrate processed by CO₂ laser cutting to improve the cutting quality. SEM (scanning electron microscope) and CLSM (confocal laser scanning microscope) observations showed that the upper and lower regions of the recast layer consist of equiaxed grains, while columnar grains dominate in the middle region, downgrading cutting quality. We used finite element modelling (FEM) to understand the solidification mechanism and explain profile and microstructure variation along the kerf. Using this analysis, we performed experiments to study the influences of assist gas pressure and laser cutting speed on the grain size and recast layer thickness. A thin, dense recast layer of uniform thickness and microstructure resulted from the following optimal parameters: 8 bar N₂ assist gas pressure, cutting speed of 1500 mm/min, and laser fluence of 200 W.