Micro Fluid Jet Polishing

Micro fluid jet polishing (MFJP) is a super-fine machining process in which a slurry of loose abrasives and carrier fluid is pressurized and pushed out through a nozzle orifice, generating a fluid beam of small diameter. Impingement of the beam onto a workpiece surface results in a submillimeter footprint of time-dependent material removal. The relatively benign processing pressure and abrasive grain size in MFJP, as compared to micro waterjet machining, assure a low material removal rate that promotes smoothing of the workpiece surface. In this chapter, the basic principles and applications of the MFJP process are first reviewed. Characterization of the process parameters, their typical value ranges, and best practice in implementing the MFJP process are discussed, together with an in-depth analysis of the process mechanism including jet plume formation, abrasive particles entrainment, material removal by particle impacts, and surface integrity considerations when using MFJP on hard and brittle materials. The basic principles of deterministic finishing by MFJP are discussed next, whereby a workpiece shape accuracy may be improved through iterative measurement and processing, with an introduction to the associated numerical methodology being provided. Finally, a number of enhancements to the MFJP process are considered, including submerged, air-assisted, ultrasonic cavitation-assisted, non-Newtonian, and magnetorheological fluid-assisted MFJP, as well as multi-jet designs of the nozzle cavity. Useful indicators are provided, as to the advantages and shortcomings of such enhancements.