Investigations on the Wear Rate of Sintering Diamond Core Bit during the Hole Drilling Process of Al₂O₃ Bulletproof Ceramics

Abstract

Bulletproof ceramics are usually hard and brittle with high elastic modulus, high compressive strength, and low tensile strength. While machining bulletproof ceramics, severe tool wear makes it difficult to obtain desired machining quality and efficiency, especially in hole drilling. In this work, an intensive experimental study on the overall wear rate of the sintering diamond thin-wall core bit during the hole drilling of Al2O3 bulletproof ceramics (99 wt.%) has been carried out. The quality loss of the bit after each hole drilled was selected for representing the overall wear rate of the bit. Based on experimental data, the influences of the main bit performance and machining process parameters on the overall wear rate of the bit have been analyzed. According to the results discussed, under the test conditions, finer diamond grit, higher diamond concentration, lower number of water gaps, thinner wall thickness, or lower bit load all can decrease the wear rate of the bit. However, within a certain range, the spindle speed has little influence on the overall wear resistance of the bit, but when the spindle speed increases, the machining efficiency can be significantly improved. The results obtained in this work can offer a valuable reference for the use of sintering diamond thin-wall core bits in the hole drilling of bulletproof ceramics.

Study on hole machining for the constant feed rate of Al2O3 engineering ceramics through low-frequency axial vibration

“…Currently, the constant pressure feed or small feed method is widely adopted for the hole machining of engineering ceramics and other hard and brittle materials. [8][9][10][11][12][13] The main shortage of the above method is uncertain machining duration and low efficiency. This study combined the novel thin-wall diamond trepanning bit and the LFAV process to realize machining Al 2 O 3 engineering ceramics under a constant feed rate.…”

“…In the large hole machining of engineering ceramics, diamond trepanning bits are mainly used for grinding holes. 8–13 Gao and Yuan 8 used impregnated diamond bits to carry out constant pressure feed drilling experiments on Al 2 O 3 armor ceramics and determined the optimum matrix formula suitable for armor ceramics. Zheng and colleagues 9–11 experimentally investigated drilling efficiency, hole quality, failure mechanism and wear loss of impregnated diamond bits when machining armor ceramics.…”

“…8–13 Gao and Yuan 8 used impregnated diamond bits to carry out constant pressure feed drilling experiments on Al 2 O 3 armor ceramics and determined the optimum matrix formula suitable for armor ceramics. Zheng and colleagues 9–11 experimentally investigated drilling efficiency, hole quality, failure mechanism and wear loss of impregnated diamond bits when machining armor ceramics. Zhang et al 12 conducted a comparative study on core drilling of silicon carbide and alumina engineering ceramics with mono-layer brazed diamond bits, studied the influence of coolant type and diamond grit concentration on drilling efficiency and discussed the surface morphology of ceramics.…”