Diamond abrasive flow‑assisted laser machining of glass microfluidic structured surface for microparticles sorting

Glass is hard and brittle, hindering precise micro‑/nanomachining of functional surfaces for glass microfluidic chips. This work presents diamond abrasive‑flow‑assisted laser‑assisted processing (DAFL) for integrated forming and polishing of glass microchannels, to reveal how micro‑/nanoscale surface features affect microparticle‑sorting performance. In DAFL, picosecond green‑laser pulses drive diamond grits for nanoscale micro‑cutting on laser‑ablated surfaces. Laser‑parameter effects on surface topography and bifurcation morphology are studied, followed by sorting tests of mixed 5 μm and 10 μm microparticles. Compared with dry and wet laser polishing, DAFL achieves controlled material removal of 0.4–0.6 μm with good dimensional retention. At 5 scans and 300–550 mm/s, roughness falls from 573 nm to 390 nm and waviness from 921 nm to 670 nm. Optimized geometry and smoothed surfaces realise stable particle focusing‑separation at low flow rates. s.