Material removal characteristics in submerged pulsating air jet polishing process

In this paper, the material removal characteristics and mechanism of submerged pulsating air jet polishing (SPAJP) process are investigated by polishing experiment on K9 glass and computational fluid dynamics simulation. The experimental results show SPAJP can etch almost perfect Gaussian footprints with high stability. Under comparable condition, SPAJP achieves nearly 300 times higher material removal rate (3.0 × 10−3 mm3/min) than that of traditional fluid jet polishing (FJP) (9.9 × 10−6 mm3/min) at the cost of a moderate degradation in processed surface roughness from Sa 3.97 nm by FJP to Sa 20.49 nm by SPAJP. Jet evolution, abrasive behavior and material removal mechanism in SPAJP are clarified by numerical modeling and experimental jet observation. It is found that SPAJP relies on jet instability of the submerged airflow beam to entrain and accelerate abrasive particles in the slurry, achieving stable and efficient polishing removal on the workpiece surface. To explore the potential of the process for deterministic polishing, an array structure surface is then designed and polished by SPAJP. The processing results are consistent with numerical prediction results, indicating that the new process has good material removal controllability which makes it applicable to deterministic polishing. This study highlights the possibility of using SPAJP to produce ultra-precise surfaces in terms of form control or fabricate high precision optical components in a more efficient and convenient manner.