Experimental Study on Peck Drilling of Micro‑holes in Fully Sintered Zirconia Ceramics Using Diamond‑Coated Drill Bits

Zirconia （ZrO₂） ceramic material has been widely applied to various fields due to its unique properties of high strength， high hardness， and excessive temperature resistance. However， the high-quality micro-hole machining of zirconia ceramic material remains a significant challenge at present. In this study， experiments on peck drilling of ⌀0.2 mm and ⌀0.5 mm micro-holes in zirconia ceramics using diamond-coated drills are conducted. The characteristics of the force signal during the drilling process， the influence of drilling parameters on the drilling force and the chipping size at the hole exit， and features of the tool wear stages of the diamond coated drill are analyzed. Experimental results suggest that when machining micro-holes in zirconia ceramics， there is a positive correlation between the axial force and the size of the chipping at the exit. The axial force increases with the increase of the feed rate and the step distance， and it shows a trend of first increasing and next decreasing with the increase of the spindle speed. The wear of the drill bit has a significant impact on the quality of the hole exit. It is found that with the continuous drilling of seven holes， the axial force increases by 144.2%， and the size of edge chipping at the exit increases from about 20 μm to more than 130 μm. This study can provide some valuable references for improving the micro-hole processing quality of material.