Helical drilling of silicon carbide (SiC) ceramic by femtosecond pulsed laser was studied in this paper. Experimental results indicated that the drilling quality was affected significantly by feeding layers. The varieties of average diameters and circularities of hole at the exit were sensitive than the entrance with different processing parameters, especially at the range of feeding layers from 5 to 25. At this time, the average taper angles also decreased notably. With the increase of feeding layers from 25 to 85, the hole shape was relatively stable at both the entrance and exit sides. The changing trend of average taper angles was similar. Although the increasing feeding layer was conducive to decrease the average taper angles, it was not obvious. This was related to the removal process of generated debris during helical drilling. The contents of Si and O were higher at the cross section near the exit than the entrance. The change of content of C was the opposite. The relationships between drilling quality and efficiency were analysed. In consideration of the drilling quality was not improved significantly with more feeding layers, it was advantageous to select fewer feeding layers in practical application.
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