- As the particle impacts the surface, it causes a small fracture, and the gas stream carries both the abrasive particles and the fractured (wear) particles away.

- Brittle and fragile work pieces work better.

- Material Removal Rate (mrr) is,

        Factors that effect the process are;

- mrr
- geometry of cut
- roughness of surface produced
- the rate of nozzle wear

        The factors are in turn effected by;

- the abrasive: composition; strength; size; mass flow rate
- the gas composition, pressure and velocity
- the nozzle: geometry; material; distance to work; inclination to work

       The abrasive;

- materials: aluminum oxide (preferred); silicon carbide
- the grains should have sharp edges
- material diameters of 10-50 micro m 15-20 is optimal
- should not be reused as the sharp edges are worn down and smaller particles can clog nozzle

       Gas jet;

- mass flow rate of abrasive is proportional to gas pressure and gas flow
 

- pressure is typically 0.2 N/mm2 to 1N/mm2
- gas composition effects pressure flow relationship

       Nozzle;

 

- must be hard material to reduce wear by abrasives: WC (lasts 12 to 30 hr); sapphire (lasts 300 hr)
- cross sectional area of orifice is 0.05-0.2 mm2
- orifice can be round or rectangular
- head can be straight, or at a right angle

        The relationship between head, and nozzle tip distance;