Analysis of micro-drilling of glassy ceramic Macor nozzles for scanning droplet systems

This paper presents a new approach called spindle-peak-frequency (SPF) for determining stable micro-drilling parameters. The novelty is that the approach does not require a force model, material behaviour of the workpiece, modal stiffness and damping of the drilling tools. The only required parameter is the natural frequency of the drilling tools, which is obtained by modal dynamic finite element analysis (FEA). Material constants for the Johnson–Cook material model for Macor are obtained and implemented into a FE model of orthogonal cutting to investigate the cutting mechanisms. The results have shown that the cutting mechanisms of the Macor are achieved by initiation and propagation of micro-cracks. Finally, the developed research methods have been implemented to manufacture Macor nozzles of scanning droplet systems where holes with diameter of 100 μm and aspect ratio of 10 have been successfully drilled which has increased the resolution by 5 times.