关键词: 微孔抛光, 空泡, 微射流, 磨粒流

Abstract: A novel micro-hole polishing method was introduced, this method applied the laser plasma shock waves, cavitation bubble shock waves of bubble collaps and jet to push the abrasive particles to polish the micro-holes. A high-speed camera and a silicon piezoresistive high-frequency dynamic pressure sensor were utilized to research the mechanism of the micro-hole polishing. Then the experiments of 304 stainless steel pipe polishing  were carried out based on different laser energy, different laser pulse number and different laser pulse frequencies, which were found that the surface roughnesses were improved with the increasing of laser energy(from 7mJ to 21.6mJ ) and laser pulses number(from 0 to 7000), but the different laser pulse frequencies(from 1Hz to 10Hz ) might not improve the surfaces roughnesses of the micro-holes. Finally, the polishing effectivenesses of different positions along the stainless steel pipes were studied, it is found that the polishing effectivenesses at the entrance of the pipes about 1~1.5mm are better than the middles and ends of the pipes. Through the experiments of micro-hole polishing mechanism and experiments based on laser-induced cavitation bubbles, it is pointed out that the plasma shock wave, the cavitation collapse shock wave and jet work together during the micro-hole polishing, and the general rules of micro-hole polish are obtained based on laser-induced cavitation bubbles.

Key words: micro-hole polishing, cavitation bubble, microjet, abrasive flow machining